Thal Equine LLC
Regional Equine Hospital • Horse Owner Education & Resources
Santa Fe, New Mexico • 505-438-6590

Equine Health Articles

We have a longstanding commitment to client education. Dr. Thal has published numerous articles for horse owners, all available below. We also offer workshops and seminars on equine healthcare. In addition, we recommend the articles found on The, a very good publication that contains a wealth of information about equine healthcare.  You must set up a free account to view the articles on-line, but it is well worth it.




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Back Problems in Horses: Understanding a Mysterious Part of Equine Anatomy While back pain is poorly understood in human medicine, equine back pain is even more difficult to comprehend, diagnose and treat.  We start with an animal who can’t tell us where or how it is experiencing pain.  This animal is so massive that we only have access to the very “shallow” layers by touch, radiography and most other diagnostic equipment.  The spine is buried up to a foot deep in heavy muscle and tough connective tissues sheets. Now introduce tack, the trainer’s and rider’s interpretations of the problem, and the placebo effect - and we are faced with a difficult and confusing problem to solve. COMMON SIGNS OF EQUINE BACK PAIN Signs of equine back pain are usually subtle and are often confused with those caused by other problems, including behavioral issues.  Some horses are more sensitive to back pain than others or respond differently to it and show more obvious signs.  The most common signs I hear associated with back pain are: Some reduction in performance, in whatever discipline the horse is engaged in.  This can be difficult to separate from rider, trainer and horseability and performance, and from low-grade lameness. Behavioral problems such as rearing or bucking.  This can be challenging to differentiate from that caused by training and riding problems. Rider or trainer report of apparent soreness to touch or pressure on the back.  Responses to back pressure and manipulation differ among horses and interpretation differs between examiners.  Just because a horse reacts does not necessarily mean that it is experiencing significant back pain. Resistance to saddling, or trouble shoeing.  Again, the challenge here is to separate true back soreness from behavioral and training problems or other physical problems. EQUINE BACK ANATOMY & FUNCTION The most important thing to know about the anatomy of the equine back is that it is very complicated.  There are hundreds of joint surfaces and small stabilizing ligaments.  There are massive muscles and thick ligaments that are attach adjacent vertebrae to one another, to the skull, and the vertebral column to the limbs.  There are multiple, intersecting sheets of extremely tough and thick connective tissue surrounding the spine.  Nerve roots exit from the spinal cord through small spaces between and in the vertebrae and course between the sliding planes of connective tissues.  Vertebrae have spines of bone that project upward or outward and to which the back muscles attach.  Only the very tips of these spines can be felt along the horse’s back.  The spinal cord is located far deeper in the back than most horse people think. The vertebrae (the individual back bones) are essentially cube-shaped bones separated by joints.  There are four distinct regions of the equine back, each of which have uniquely shaped bones and joints and different ranges of motion.  In each region, unique vertebral design, joint design and support and muscle attachment allows for more or less flexibility side to side, up and down and in rotation.  The basic form and function of the equine back is critical information in understanding back pain and the causes of and treatments for that pain. Desirable back conformation is also very important for an animal that is expected to perform athletically with the weight of a rider on its back. DIAGNOSIS OF BACK PAIN Veterinary examination of the equine back is difficult.  The muscles are so heavy and thick that it is impossible to evaluate the deeper structures that might be involved simply by feel.  That said, a thorough physical examination (at rest and in movement) is still the cornerstone of diagnosis.  When I evaluate a horse for back pain, I do the following: I first look at the whole horse and evaluate the general conformation and symmetry of the back. I palpate accessible muscles, ligaments and bony prominences and evaluate them for normal tone, shape, size, symmetry, and pain depending on the structures examined. I evaluate different regions of the back for motion on several planes and gauge the response to attempted manipulation. I attempt to rule out lameness that might underlie the back soreness.  I do this by examining the limbs and seeing the horse in motion. In many cases, I evaluate movement both with and without a rider. Finally, if I feel it is indicated, I may evaluate tack fit. ADDITIONAL DIAGNOSTICS Depending on the circumstance and my findings during a thorough clinical exam, I recommend diagnostics that may provide additional information helpful to reaching a definitive diagnosis: I often take radiographs of the neck and withers.  Quality images of the spine of the neck to the withers can be obtained with today’s x-ray generators and digital technology. The vertebral column through the barrel and loin of the horse can only be imaged with the most powerful radiographic equipment not available to most veterinarians.  If your veterinarian does not offer this capability, they can usually refer you to a facility that does. I often use ultrasound to visualize the soft tissues of the back, but it too has limitations.  Ultrasound is not good for visualizing deep structures and can only image the surface of bone.  Ultrasound can be used on the skin over the back to image areas of swelling or soreness and the normal soft tissue structures of the accessible parts of the back.  It also can be used trans-rectally to view the underside of the vertebrae that can be reached that way.  Ultrasound is being used more and more to diagnose problems of the back. Nuclear scintigraphy or bone scan can be a very useful way to find areas of increased bone turnover (and thus injury) in the back.  This diagnostic is not offered by many veterinary practices due to the cost of the equipment and the regulation imposed on users, but it is available at many larger referral practices and universities.  See Subtle or Hard to Diagnose Equine Lameness: What Horse Owner’s Should Know for more information. Practitioners of chiropractic and acupuncture tend to focus a great deal on the back. These practitioners use specific techniques to help define and treat problem areas.  There is controversy regarding the effectiveness of these alternative therapies in horses.  In my experience, the ability of these modalities to help a situation is all about the practitioner.   I generally prefer to refer my clients to practitioners that are also equine veterinarians.  I feel that these practitioners are more likely to have a solid medical background and understanding of equine anatomy and physiology. PRIMARY & SECONDARY CAUSES Primary back pain can result from lesions of the skin, muscle, connective tissue, nerves, joints and bones of the back.  These are usually a result of some traumatic injury – either an individual injury or chronic wear and tear.  Poor tack fit can contribute to or cause these problems.  Poor riding can cause or worsen problems.  Different types of primary back problems affect horses of different types, from different disciplines, and of different conformation. Secondary back pain or soreness is a result of an underlying lameness, or back soreness somewhere else resulting in a change in movement.  Hind limb lameness, especially hock pain, is frequently associated with back pain but any lameness can result in secondary back pain.  The back and limbs are linked in anatomy and function.  If a horse is not moving symmetrically and freely for any reason, soreness and asymmetry will often develop in the back. POOR SADDLE & TACK FIT The main concern of good saddle fit is that the force bearing surfaces of the saddle conform well to the horse’s back and evenly distribute the weight of the rider.  There should not be focal areas of pressure anywhere.  The saddle should be level, front to back, and sit in such a position that it favors the free movement of the horse and reduces discomfort.   A saddle that fits correctly should put the rider in a position where he or she is balanced, not thrown forward or backward. I often use this commonly described analysis when looking at a horse and rider: Look at the horse and rider from the side.  If the horse is removed from the image, the question is whether the rider would be able to balance on the ground given where their feet are located.  If not, there may be a saddle problem (or rider positioning problem) that could be contributing to back pain.  In addition, improperly adjusted or fitting bridles and poor riding can cause a horse to resist the bit and raise the head high, which causes the horse to flatten or hollow its back.  This counteracts the correct physics of the horse’s back, reducing performance and potentially leading to back soreness. TREATMENT FOR EQUINE BACK PROBLEMS If a diagnosis can be reached, treatment may involve addressing the primary contributing factors like conformation and suitability for the present use, underlying lameness, tack fit and rider technique and position.  Veterinary treatments for back pain depend on the specific nature of the injury and may involve combinations of the use of rest, change in use, anti-inflammatory drugs, muscle relaxants, direct injection of affected muscles, ligaments and joints, therapeutic ultrasound, pulsed shock wave therapy, physical therapy, massage, application of heat and cold, chiropractic, acupuncture, and many others, often used in combination. Even with advanced technology and imaging, and dozens of available treatment approaches, the equine back will likely remain something of a mystery for a long time.  Proper treatment should always start with every attempt being made at a diagnosis.  Is this primary back soreness or is it secondary to an underlying low-grade lameness?  Is there a behavioral component? While many lay practitioners may have a single perspective that has some value, your equine veterinarian is still the one who is trained to put the whole picture of your horse’s health in perspective.  They can help you coordinate your approach towards better understanding the equine back. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Bute & Banamine®: Commonly Used & Misused in Horses “Hey Doc… my horse has been colicky since last night. I gave her some Banamine® and she seemed OK for a while, but now she doesn’t look so good…”  This scenario is unfortunately still common in my vet practice.  Although my established clients know to call me before administering these medications, there are many horse owners who regularly use these two common but poorly understood prescription drugs without any veterinary guidance. Often, things work out fine, but in some cases, unguided use of this drug causes catastrophic results. [caption id="attachment_6954" align="alignright" width="150"] Bute & Banamine - Commonly Used & Misused in Horses[/caption]  “Bute” (phenylbutazone) and Banamine® (flunixin meglumine) are the most commonly used non-steroidal anti-inflammatory drugs (NSAIDS) in the horse. They are very useful drugs used for a variety of conditions and signs.  The NSAIDS for horses are prescription drugs, meaning that they can only be bought legally with a veterinarian’s prescription. Despite this, they are found everywhere in the horse world, and they are often administered to horses without veterinary oversight and without any knowledge of drug action or potential side effects. WHAT IS INFLAMMATION & WHY STOP IT? Inflammation is a natural, intricate series of biochemical reactions that takes place in all animals as a response to injury. Inflammation, the first stage of healing, involves complex reactions between local damaged cells, blood vessels, inflammatory cells and biochemical signals sent and received from cells both near the site of injury and far from it. The first results of inflammation include opening of blood vessels to the area (reddening and heat), increased leakiness of blood vessels (swelling), and attraction of infection fighting white blood cells to the site. Products of inflammation include prostaglandins and other inflammatory “mediators” that help bring about these effects.  Some of these mediators directly cause pain. All of these products of inflammation are intended to rid the body of infection or injury, and to prepare it to for healing. Inflammation is a natural process and it is critical for survival. The problem is that often this process becomes excessive, creating a vicious cycle and causing more tissue damage and pain than the injury itself might. This is where anti-inflammatory drugs are helpful. Their role is to dampen inflammation by reducing the formation of these mediators, and thus reducing the signs of disease (swelling, pain and fever, for example) while still allowing healing to take place. NON-STEROIDAL ANTI-INFLAMMATORY DRUGS – “NSAIDS” Bute and Banamine® both belong to a class of drugs known as non-steroidal anti-inflammatory drugs (“NSAIDS”), which includes familiar human drugs like aspirin and ibuprofen. Less commonly used equine drugs in this class are firocoxib (Equioxx) ketoprofen, carprofen, naproxen and many others. These drugs moderate inflammation by stopping the formation of prostaglandins, which are pivotal mediators of inflammation.  By doing this, they also reduce the formation of certain pain-causing products of inflammation. But anti-inflammatory drugs do much more than simply control pain. They also reduce swelling and fever. They have value in treating a wide range of conditions in horses, from abdominal pain (colic) to joint injury and laminitis. NSAIDS reduce inflammation by blocking prostaglandin synthesis. Prostaglandins come in many types. Some are products of the inflammatory cascade, while others have vital maintenance functions in the body. For example, one type has the role of protecting the stomach and intestinal lining from acid and digestive enzymes. This same prostaglandin has a protective role in the kidney.  Unfortunately, NSAIDS not only decrease the production of “bad prostaglandins” of inflammation, they also reduce the formation of these “good prostaglandins” and can cause problems to organs normally protected. In recent years, new types of NSAIDS have been developed. Increased safety and fewer side effects are advantages of these newer drugs. They are called “selective” meaning that they are formulated to target the “bad” prostaglandins of inflammation and spare the protective ones. Currently, the most prominent of these in the equine world in the United States is firocoxib (Equioxx). Having used the drug now for a number of years, I find that it too has a niche in my vet practice. I use it for longer courses of administration or when I am especially concerned about side effects. But no drug has yet provided a perfect balance of great effectiveness and excellent safety. Bute and Banamine® remain the mainstay of anti-inflammatory therapy in the horse. The vast majority of horses treated with these medications have no noticeable problems from their use. On the other hand, all NSAIDS have potential side effects that include: Intestinal and stomach side effects including gastric and colonic ulcers. Foals are especially sensitive to the intestinal side effects and easily develop ulcers from the use of these medications. Kidney problems. This is especially true of young horses, but caution should always be used, especially in old horses and those that are otherwise ill or dehydrated. Importantly, NSAIDS have the ability to “mask” a problem, making it look less severe than it really is and give cause for false hope and delayed treatment. For these reasons, it is very important to consult your veterinarian before you administer these drugs to your horse. “BUTE” – PHENYLBUTAZONE Phenylbutazone (a/k/a butazolidin) is primarily used to relieve musculoskeletal pain and inflammation in the horse. Bute comes in several forms including an injectable liquid for intravenous dosing only. It is most commonly found in oral forms: paste, tablets and powder. Used correctly, bute is a powerful and effective means of relieving pain and inflammation. Nevertheless, there are potential side effects. Bute is unsafe in all horses at high doses for long periods of time. Some horses are much more sensitive to bute than others and may show side effects to smaller amounts. Bute is considered more likely to cause ulcers, especially in the large colon, than Banamine® and other NSAIDS. Bute is processed, inactivated, and removed from circulation by the liver and kidneys. Young horses have not fully developed their ability to process this drug, and tend to accumulate toxic doses of it. The same concern applies to horses with underlying kidney or liver disease. Bute is highly effective for treatment of lameness. As a consequence, it can mask signs of mild or moderate lameness. A horse with a serious musculoskeletal injury may over-exert, and thus worsen the injury.  Bute is somewhat less effective than Banamine® at controlling abdominal pain (colic) but can still be useful. Non-veterinarians should not use the injectable form of this drug. It is for intravenous use only, and must never be given in the muscle. It is severely damaging to tissues if even a small amount escapes the vein during injection. Severe swelling develops and the tissue may even die and slough out, leaving a huge open wound that can take months to heal. Bute at a low dose can be useful and quite safe for long-term maintenance of horses with chronic pain. There are now safer (although more expensive) alternatives for longer-term treatment. General guidelines for using bute: The best option is always for a veterinarian to examine any undiagnosed lameness or disease process. When you give a dose of bute to a horse without veterinary oversight, recognize what you are doing. You are temporarily relieving inflammation and pain, regardless of the diagnosis. If you do plan to use bute to try to treat undiagnosed lameness, ask your vet for an appropriate dose for pain control and what to look for to determine treatment effectiveness. Confine any lame horse treated with bute in a small area, to prevent worsening of injury due to overuse. Do not force exercise while on bute. Do not use the injectable form of this drug because of the dangers of improper injection. For clients that understand these concerns: I dispense oral bute paste, powder or tablets to my clients for whom I have a valid VCPR (Veterinary-Client-Patient Relationship) as needed for treatment. BANAMINE®  – FLUNIXIN MEGLUMINE Banamine® is a trade name for the anti-inflammatory drug flunixin meglumine.  Banamine® was the only brand of this drug available for many years. As a result, the brand name stuck, despite the fact that the drug is now available generic from many manufacturers and has many different trade names. It is available in injectable solution for IV use, a paste formulation, and granules. Although the injectable drug is intended for IV use, many horse owners give flunixin intramuscularly, and the injectable solution is actually also absorbed given orally (extra-label use). This drug is somewhat irritating to the tissues when given in the muscle and in rare cases can cause significant muscle damage and severe bacterial infection. Banamine® is best known for its use in horses with abdominal pain – colic.  No doubt, this drug is a potent pain reliever and it has extra anti-inflammatory benefits that make it especially good for treating intestinal problems. It is thought to break the pain-dysfunction cycle that occurs commonly in colic cases, thereby allowing the gut to regain function. Unfortunately, this drug is also excellent at masking the signs of colic, giving horse owners the false belief that they have “cured the colic” only to find their horse is critically ill or dead the next day. Colic is not a disease but is the horse’s way of demonstrating abdominal pain. If the cause of colic pain is simply gas or a spasm, a “simple shot of Banamine®” may be all it takes to break the cycle and solve the problem. If, however, there is a mechanical problem in the gut such as a severe feed impaction or mechanical displacement, Banamine® might temporarily make the horse look better but does nothing to fix the underlying problem. Unfortunately, this improvement can mislead horse people into believing their horse has been cured. The time wasted thinking that the horse has improved can be the difference between life and death. Guidelines for using Banamine to treat horses showing signs of colic (abdominal pain): First, call your vet to alert them to the colic episode and to the fact that you are giving Banamine®. Decide whether or not you will take a wait and see approach or will have a vet call. The safest thing is to have your vet examine your horse. Take away all feed until your vet recommends replacing it. Once the horse looks better, only offer what fits in the palm of your hand, and only to test appetite. Assuming the horse looks normal after the shot, monitor them every 1-2 hours, paying particular attention to attitude and appetite, intestinal sounds, heart rate and gum color. See the Whole Horse Exam (WHE) (for more info on the WHE, see our website). The masking effects of Banamine last 6-12 hours. Your horse could return to colic pain when the pain relieving effects begin to wear off. If a horse seems completely normal and with normal appetite past 8-12 hours post-administration, chances are that the problem causing colic is resolved. This is when slow return to feeding (as per the advice of your vet) can commence. CONCLUSION Bute and Banamine® are extremely important drugs in equine medicine. They offer excellent anti-inflammatory and pain relieving effects for horses. But they must be used appropriately. You should understand the basic concepts of how these drugs work, their strengths and limitations.  Always talk to your vet before you administer these drugs. A veterinarian should evaluate any horse with persistent colic signs or other illness, in order to diagnose the underlying cause and determine whether other types of medical or surgical treatments are required. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated May 2014   Would you like to learn more about bute and Banamine® on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:               Observation - Abdominal Pain, Colic Signs       Observation - Bute, Banamine®, NSAID Overdose       Treatment - NSAIDs, Non-Steroidal Anti-Inflammatories       Skills - Give Intramuscular (IM) Injection       
Camping & Packing with Your Horse: A Veterinarian's Perspective The most common veterinary emergencies on the trail are colic, wounds (including rope burns), lameness, and “tying up.” While accidents happen to even the best-prepared, thinking ahead and knowing the basics can prevent most of these problems.  The best approach is always to try to avoid emergencies by ensuring that you and your horses are prepared for the outing in every way.  Below are some basic guidelines and tips for avoiding problems and making your equine outing the great experience it should be. PREPARATION It is vital that your horse be properly vaccinated for your trip.  Travel and camping in a group of horses exposes them to stress and potentially to new disease organisms. Horses that have never been vaccinated before must have received the primary series of vaccine early enough before your trip to allow their body time to mount an immune response. For horses that have been maintained on a vaccination program in the past, talk to your veterinarian about vaccinating them with a booster at least a month prior to your departure. Standard equine vaccines in our area are Eastern and Western Encephalitis, tetanus, West Nile virus, influenza and rhino. Strangles has been a problem in some camping areas and boarding stables.  Discuss the costs and benefits of this vaccine with your veterinarian. See also Deciding When to Use "Risk-Based" Vaccines.  Camping in the back country implies greater exposure to rabies.  For this reason, you should also discuss rabies vaccination with your veterinarian. OTHER HEALTH REQUIREMENTS Horses should be properly dewormed and should have no other health problems. Shoeing should be current and appropriate. Interstate travel requires proof of a negative Coggins test (negative for equine infectious anemia) and a health certificate.  Most states require that this test be dated within the past year.  Some states have special requirements. Health certificates are generally only good for up to 30 days, again depending on State. Get the Coggins test and health certificates taken care of well in advance so that there is not a rush before your trip to get them done. In addition, owners of horses in transit often are required to show proof of ownership – hauling or brand inspection papers.  Check with your veterinarian to learn the requirements and to be referred to your local livestock inspector, who can provide these to you. CONDITIONING YOUR HORSE Physical conditioning of your horse for major trail riding and horse camping is critical to a good experience.  You should ideally start any conditioning program at least 4 to 6 weeks prior to the ride.  That said, conditioning a horse starting 2 weeks in advance is better than nothing.  Your horse should be accustomed to the type of work you will be asking him to do.  If the ride will cover miles of steep trail daily for 3 days, then your horse should have ideally experienced similar trail types. Trail riding 2 to 3 times per week for 30 minutes to an hour per session can prepare a horse for long trail rides.  Adding inclines to your training regimen is a good idea if you the trip will involve lots of vertical gain. Ring work can be a substitute for long training rides, but you may need to push the horse a little harder and engage the hind end in the exercises you choose. Mental conditioning of your horse (and you) is just as important to the enjoyment of your trip as physical conditioning.  Address training issues like loading, trailering, tying, catching, and “fear of water” before your trip, rather than on it.  This may mean getting some help if you are not able to resolve these problems yourself.  If you plan to ride in a group of unfamiliar horses, try to get your horse prepared for this.  Horses that are not accustomed to being around strange horses may expend lots of nervous energy just interacting with them.  This can add to stress and overexertion. OTHER SUGGESTIONS Have a check list of needed items prepared in advance. Have a good map and be clear on your destination and camp sites.  Give yourself plenty of time to get to your destination and get your camp set up.  Procrastinating and rushing (as I always do!)  is a sure way to cause a problem. Briefly examine your horse before you load up.  Is his attitude OK?  Are his shoes OK?  Does he trot sound in a quick circle to both directions? If you are taking a pack animal, you should be knowledgeable in balancing loads and your tack should fit well. Check your rig beforehand, including all aspects of your trailer to ensure that it is ready. Your riding habits on the trail are very important.  You should encourage your horse to graze and drink frequently. Maintain an easy, even pace whenever possible. As you ride, watch for excessive sweating, heavy breathing, or resistance to moving forward.  Stop immediately and allow rest if your horse experiences any of these symptoms.  Stop periodically, especially during strenuous exertion, and allow your horse to rest until his heart rate comes down. Allow him to eat and drink during this rest time.  If his recovery time is slow, be prepared to give him adequate rest periods for the rest of the ride.  For pack animals, it is critical to watch the load carefully for imbalance and other problems. Cool your horse out by walking him quietly over the last couple of miles.  This is especially important in cold weather, so that he doesn’t get chilled after coming in wet with sweat.  In warm weather, give him a bath and scrape him off.  Daily, after your ride, you should check for saddle sores, swellings or cuts, especially down low on the legs.  Ensure that he can trot soundly in a circle.  Ensure that his attitude and appetite are good. If your horse is fine at the end of the day, and cooled out properly, he can be fed a typical ration.  If there is any question, only feed him a light meal.  If he is not accustomed to green grass, only give him access to small amounts initially, gradually increasing this over the trip.  Always try to avoid sudden major diet changes.  Secure your horse for the night in a safe way. This might involve portable corrals, portable electric pen, tying to a picket line, or another method.  The important point is that you do it correctly to avoid accidents. FIRST AID KIT Talk to your veterinarian about helping you put together a first aid kit for the trail.  Here is a list of common items taken on the trail: Paste electrolytes. (Talk to your veterinarian about the best one to purchase, as they are not all equal.) Basic bandage material. Fly repellent ointment or wipe. A prescription anti-inflammatory paste and an oral antibiotic on hand for emergencies. Your veterinarian should explain how and when to use these drugs if he or she dispenses them. I like to take a collapsible bucket, a small jar of antiseptic soap, a tube of antibiotic eye ointment, and a tube of ointment for rubs and sores.  I also carry a disposable shaver and a digital thermometer.  I take what I need to reset a shoe if I need to. If you are not sure of how and when to use veterinary drugs and supplies, you are better off without them. Ensure that any drugs you take are packaged properly so that they are not spilled or broken as the load shifts.  You should balance preparing for any emergency with trying to travel as light and simply as possible. It is preferable to avoid accidents and veterinary emergencies through good preparation and horsemanship rather than to fill your pack with veterinary supplies to cover every potential accident.  Have your horses and yourself prepared well, so that you have an enjoyable and less stressful experience. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Care & Management of the Growing Foal (Newborn): Part 1 This is the first of two articles on the young foal from birth to weaning.  The purpose of the first article is to take a short journey from the separation of the umbilical cord through the first week of life.  I touch on some of the important points of care and common problems you should be on the lookout for.  One recurring theme is to observe the young foal carefully, and promptly discuss with your veterinarian any questions that come up.  I advise my clients to be careful not to dive in to treat foals themselves unless they are confident in what they are doing.  Sometimes well-meaning owners do more harm than good when they try to help their young foals. Horse people intuitively know that the foal’s first days of life are a critical time.  This is an exciting and idyllic time for both foal and owner.  Behind the scenes, every part of the young foal is developing rapidly and adjusting to life outside of the mare.  The young foal’s body systems are very fragile and sensitive during this period. Problems like diarrhea, colic and infected joints can progress rapidly in the young foal and quickly become life threatening if not treated appropriately. Improper management or nutrition may lead to irreversible problems. In the growing foal, other problems like Developmental Orthopedic Disease (DOD) may be subtle and might go undetected if owners are not on the lookout for these problems.  Good management and an understanding of the common problems that can arise in this age foal can help ensure that the young foal grows normally and reaches weaning strong and healthy. It’s 2 a.m. and with a final hard press from the mare, the newborn foal (a colt) lies near its mother in the clean, fresh straw.  Its face is free of the placenta, and it is already trying to get its head up and roll on its chest. It’s best not to rush in unless you know there’s a problem.  The mare will get up in a minute and she will likely break the umbilical cord then, as nature intended.  Cutting the umbilical cord sharp or too close to the foal’s body can result in umbilical disease later.  It’s also not advisable to treat the umbilical stump with strong antiseptics.  Many foals end up with umbilical infections from overzealous treatment of the umbilicus with strong antiseptics.  I advise treating it once only, with a dilute antiseptic (chlorhexidine) solution. It’s 3 a.m. and after a dozen tries, the foal has gotten up on his own and he is now nursing. Most baby foals are up within an hour of birth but some can take a little longer.  They should nurse within another 30 to 60 minutes. The mare should have passed her placenta by now.  Placentas are considered retained after three to four hours.  A retained placenta is an emergency and must be resolved quickly by your veterinarian. It’s now 5 a.m., the foal has been up and nursed multiple times, and is now laying down sleeping. The first day of the newborn’s life is an eventful one.  The normal pattern for the young foal is to nurse frequently and then nap, with much of the time spent sleeping. It's 9 a.m. and the little colt is already bouncing around the stall and nursing vigorously.  He stops, lifts his tail and seems to strain and push. Constipation of the first manure (meconium) is common enough in the first day of life that many breeders give a routine enema. Meconium impaction is more common in colts than fillies.  It is important to discuss this straining with your veterinarian when he or she arrives for the exam.  He or she will likely give the foal an enema and ask you to monitor the foal closely to ensure that he continues to pass manure normally.  Most minor impactions resolve with an enema. Diarrhea is also a common problem in the newborn foal and is potentially fatal.  It is usually caused by bacterial infection.  If you notice diarrhea in the foal at one to five days of age, immediately communicate with your veterinarian. Your veterinarian arrives and does a careful examination of mare, placenta and foal. The mare is healthy and the placenta is complete and normal.  The veterinarian is now examining the foal, with an assistant handling the foal. Foal handling is an art.  It should be easy on the foal, mare and on the handlers.  Gentle but firm and correct handling of the foal at this stage can pay great dividends later on.  Many owners “imprint” their foals at this time.  My suggestion to horse owners about imprinting is to do it right or don’t do it at all.  Poor handling can be stressful to the foal and might get your relationship off to a rocky start.  There are plenty of books and resources out there that can help you learn the proper techniques of early foal handling. I recommend a veterinary exam for every newborn foal.  When the foal is 8-24 hours old, I do a careful examination of the mare, the placenta and the foal.  In the foal exam, I look carefully at attitude and general health.  I listen to its heart, lungs and abdomen. I inspect the umbilical stump, joints, mouth and eyes. I carefully examine the foal’s legs.  I do not believe in giving vaccinations, vitamins or antibiotics to newborn foals unless I know they are ill or are at risk for a problem. Importantly, I take blood to check for antibody levels (IgG) that was absorbed from the first milk (colostrum).   All foals must ingest good quality colostrum within the first hours of life.  A change in the intestinal lining, called closure, takes place in the foal’s intestine after 18 to 24 hours of life.  After that, the foal can no longer absorb the colostrum’s vital antibodies from its intestine.  Failure to ingest this antibody is called Failure of Passive Transfer (FPT).  FPT is a common problem for foals and must be treated correctly and immediately.  If the foal fails to nurse normally, it must ingest good quality colostrum from its dam or another mare by stomach tube or bottle within hours of birth.  Failing that, it must be treated with intravenous plasma containing the necessary antibody.  If the foal does not receive adequate antibody, it will be incapable of fighting disease and will usually not survive.  Commercial colostrum supplements are no substitute for adequate colostrum. Your veterinarian comments that your foal has flexor tendon laxity and mild angular limbs. You had noticed earlier that his rear fetlocks seemed to sag almost to the ground and his toes come off the ground slightly.  This is a very common problem in young foals.  It can occasionally be serious but usually resolves quickly on its own, as the foal gains strength. The opposite problem of the tendons being too “tight” is also fairly common.  This is called flexural deformity and usually means that the affected joints are over-flexed, or too upright.  The most common area for this problem is the lower limb, either the fetlock or the foot itself.  It is important to discuss any limb problem with your veterinarian right away.  Early and appropriate treatment is critical for getting good results. [caption id="attachment_7017" align="alignleft" width="144"] Foal - Angular Limb Deformity - Before Surgical Correction[/caption] [caption id="attachment_7018" align="alignright" width="144"] Foal - Angular Limb Deformity - After Surgical Correction[/caption]   “Angular limbs” is a term that refers to abnormal deviation of the foals limbs when viewed from the front or back.  In the first few days of life, many normal foals have very crooked looking limbs.  Your veterinarian can advise you as to what is normal and what is not.  Most angular limb problems resolve on their own, but others require treatment and may involve stall confinement, splinting and even surgery.  Surgical procedures mostly rely on impeding growth on one side of the limb while the other side continues to grow normally, thus straightening the limb.  Within weeks, the bones of the lower limb stop growing in length and treatment may be impossible. “Foal Heat Diarrhea” is a normal diarrhea that occurs in foals at one to two weeks of age.  The mares' “foal heat” (the first heat after foaling) usually coincides with this period of foal diarrhea, however the diarrhea is probably not caused by the mare being in heat.  Your veterinarian will likely ask you to just watch the foal and ensure that he continues to nurse well and act normal.  You may also be told to smear some Vaseline or A&D ointment under the foal's tail and down the hind end to prevent scalding.   Usually this diarrhea resolves spontaneously.  Occasionally, a foal has persistent or more serious diarrhea.  In those cases, I try to diagnose a cause and start treatment. We have taken a short journey with our newborn foal from birth through his first week. In Part 2 of this article, we’ll follow him along through the period from two weeks to weaning. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Care & Management of the Growing Foal (One Week through Weanling): Part 2 In Part 1 of this article, I discussed management and veterinary considerations for the baby foal from birth through one week of age. In this article I continue with some important health considerations for the growing foal from 1 week old to weaning.  The period through weaning is a critical time for the developing foal.  Healthy growth is critical for horses to reach their full athletic potential. The young colt from the last article is beginning to eat some of the mare’s feed.  You notice that that he eats manure.  He is vigorous, nursing well, and seems to be growing rapidly.  You notice that he has some diarrhea still.  You also notice that he has what seems to be an abnormal angle of the right front fetlock when viewed from the front.  As he grows, you notice swellings appearing just above his fetlock joints. These are typical observations made by those involved in the care and management of nursing foals.  In this article, I address these concerns with emphasis on nutrition and developmental orthopedic disease, what I consider to be the most common problem in this age foal.  I also discuss infected joints, vaccination and parasite control. Proper nutrition is a critical part of managing the nursing foal.  At one to two weeks, the foal is eating solid feed in addition to nursing many times per day.  The foal sleeps much of the day between meals.  Manure eating is normal.  The foal populates his intestine with the essential bacteria and protozoa in the mare’s manure.  At two weeks, foal heat diarrhea is usually resolving, but a small degree of diarrhea may last for weeks and still be considered normal. RAPID GROWTH Up to six weeks of age, most of the foal’s nutrition comes from milk.  Starting at six weeks and through weaning the mare’s milk production gradually declines and the foal eats more and more solid feed.  The most common nutritional problem for foals of this age is over-nutrition and excessively rapid growth.  Foals drink large quantities of milk and in addition are often being supplemented, or are eating the mare’s grain.  Excess energy in the feed causes the foal to grow faster than it should.  This causes problems for the developing musculoskeletal system. These problems are grouped into a category known as Developmental Orthopedic Disease (DOD). The syndromes that make up DOD mostly involve problems with the lengthening of bones with growth.  This process involves converting soft cartilage to bone in a lengthening section of the bone known as the growth plate (physis).  There are areas of enlargement in the bone accounting for both increased length of the bone (physis) and enlargement of the joint (epiphysis).  Physitis affects growth of the lengthening long bone at the growth plate.  Osteochondrosis (OCD) affects growth of the bone underlying the joint.  This syndrome is also associated with “Wobbler Syndrome,” spinal compression from abnormally developed vertebrae in the neck. Physitis is caused by defective bone growth at the physis, or the area where bones are lengthening.  This causes swelling, pain and may cause lameness.  This problem can also be related to angular limbs through excessive loading of one side of the growth plate.  A foal afflicted by physitis might seem sore and stiff, and have visible swellings, usually above the joints of multiple limbs.  In the young foal these swellings are mostly just above the fetlock joints. Osteochondrosis is caused by defective bone formation in the area directly under a joint.  This causes a faulty foundation for the joint, allowing the joint surface to be irregular or even collapse, causing eventual lameness and arthritis.  This problem often is not discovered until training commences. Excessively rapid growth may cause these problems the following ways: Overweight foal.  Subjecting the delicate bone lengthening process to too much weight per unit area. Excessive Exercise.  Moderate exercise is critical to healthy foal development.  Foals that are fed a high-energy diet play more than foals that are fed a more moderate diet.  This excessive exercise may irritate the physis by overloading it. Inadequate Nutrients.  Excessive rate of growth at the growth plate may outpace the availability of other nutrients needed for healthy bone growth. Growth-related problems can also result from other factors such as: Lameness in one limb can cause overload of the growth plates in the other limb. Genetics likely plays a role both in the tendency to have physitis/ OCD and in the potential for growth. Under-nutrition and improper mineral balance.  Protein deficiency and imbalances of levels of calcium, phosphorus, copper and zinc have all been found to be involved in the development of some cases of DOD. PREVENTION OF DEVELOPMENTAL ORTHOPEDIC DISEASE - DOD Over-nutrition is the most common cause of developmental orthopedic disease.  A foal generally cannot consume enough grass hay to cause a problem.  Over-nutrition usually results when the foal is supplemented with additional grain or alfalfa or is eating too much of the mare’s grain or alfalfa. Do not overfeed foals.  Pay attention to body condition of mare and foal.  If necessary, separate mare and foal for supplementation as needed. Provide balanced nutrition.  There are now many commercial, pelleted feeds designed for the growing foal.  These generally have a good balance of energy, protein and necessary minerals.  I recommend using these products rather than grains and large quantities of alfalfa to supplement foal diets. Know the signs of DOD and be on the lookout for them.  Deal with them promptly by contacting your vet right away. Genetics: Breed individuals that do not have a history of these problems. Careful observation is key.  It is very important to observe your foal’s legs as it grows and to know normal “correct” conformation. Flexural and angular limb deformities are deviations from correct limbs.  Flexural deformities refer to abnormalities you can see when viewing the limbs from the side.  Flexural deformities usually affects the joints of the lower limb and can appear at birth or be acquired, developing with time.  Flexural deformities relate to a relative shortening of the flexor tendons of various joints.  An example of a flexural deformity is “Club Foot."  This is an abnormally upright hoof, which can be severe enough that the heel may be off the ground. Angular limb deformities are abnormal angulations at joints, visible from the front or back.  Your veterinarian can help you decide which of these problems will resolve spontaneously and which require treatment.  Treatment for flexural deformities and angular limbs depends on the case and may involve exercise restriction, splinting, medications, surgery or a combination of these treatments. The most important thing you can do is to recognize that these problems exist and know what to look for.  If you have questions, call your veterinarian promptly.  Early treatment of developmental limb problems is the key to their successful management.  Delay causes irreversible change as the growth plates “close."   This starts happening in very early life, depending on the specific growth plate in question.  In addition to evaluation by a veterinarian, foals with angular limb and flexural deformities should have their feet trimmed and balanced regularly by an experienced farrier. OTHER IMPORTANT MANAGEMENT CONSIDERATIONS Young foals with severe lameness should be examined promptly by a veterinarian.  A common cause of severe lameness in foals is septic arthritis (infected joint).  An infected joint is a life-threatening problem and must be treated aggressively and correctly.  This catastrophic problem usually results from spread of bacteria into the blood from intestinal, umbilical, and other infections.  These blood borne bacteria then seed the joints, starting infection.  Always keep an eye on the young foal’s umbilical area for swelling or drainage.  Be aware that even if you cannot see swelling of the umbilicus, infection can exist, allowing bacteria into the blood. FOAL VACCINATIONS Foals out of mares that are current on their vaccination should be vaccinated the first time at four months for Encephalitis, Tetanus and West Nile Virus.  Keep in mind that all foals require a second booster shot three to six weeks after the first.  Studies suggest that it is best to wait to vaccinate foals for influenza and rhinopneumonitis until they are 6-12 months old.  Other vaccines may be given based on advice of your veterinarian. There is a reason not to vaccinate foals too early.  A newborn foal gets its immunity from the mare’s colostrum or first milk. The concentrated antibodies from this colostrum are absorbed during the first day of life and this antibody is protective for the first few months of life.  Giving a vaccine while these antibody levels are high is counterproductive.  The vaccine itself (which is a prepared part of the actual virus) becomes bound up by the antibody in the foal's blood.  In this way both antibody and vaccine are used up, leaving the foal unprotected against disease.  Foals out of mares not currently vaccinated should have their vaccination program started at two months instead. PARASITE CONTROL Parasite control in the young foal is important.  Young foals are very susceptible to internal parasites.  I recommend monthly small doses (by weight) of safe products (ivermectin alternating with pyrantel is an example), beginning at one month of age and through a year.  The foal’s mother and any herd mates should be on an every two month worming schedule as well.  It is important that this is coordinated with the foal’s schedule. The period through weaning is a critical time for the young foal’s development.  Careful management of nutrition and prevention of DOD during this time is important to maximize future athletic potential.  Other important considerations discussed here are vaccination and parasite control, but this article only touches on a few important aspects.  There are many other factors that must be considered in perfecting management of the growing foal.  The better the management, the better the likelihood of producing a weanling that reaches its full potential for development and future performance. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Colic Surgery: What Horse Owners Should Know (Revised 2014) [caption id="attachment_4400" align="alignleft" width="300"] Tonight you must make a quick decision about your very best horse - proceed with emergency colic surgery or put him down (euthanasia). What do you do?[/caption] Imagine that tonight, at midnight, you are told that you must make a decision about your very best horse.  Your choice is to either have colic surgery performed on the horse, or he will need to be euthanized.  You have 20 minutes to make the decision, because he is suffering in severe pain and is a danger to himself and his handlers.  There is no certainty as to what the outcome of surgery will be, whether he will survive and return home or be alive in a year.  Will he be able to perform at the level that he did before, or will he live a quality life after surgery? You have never even met the veterinarian who is giving you these options.  Your regular veterinarian referred you to this equine hospital after 2 hours of treating your violently painful horse in the field to no avail.  Should you proceed with surgery, you must provide the surgical facility with a deposit of $3,000 -$5,000. The total cost may range from $8,000 – $12,000, or even more if there are complications.  What should you do? In the midst of this crisis, there is rarely enough time for me to tell clients all they need to know.  So I felt it was important to describe colic surgery and answer some of the more frequently asked questions. My goal is for horse owners to go into the process better informed. WHAT IS COLIC? Colic is a sign of disease, not a disease.  It is a sign that something else is wrong – it is not the problem itself.  The word “colic” refers to the signs that horses show when they are experiencing abdominal pain. This pain usually results from an intestinal condition, but it can result from problems of other organs as well.  Signs of abdominal pain (colic) in the horse include: loss of appetite, lying down, pawing, rolling, kicking at the belly, looking at the side, stretching and many others. The horse’s intestinal tract is very complex, about 100 feet long, and made up of distinct anatomic parts, each of which has unique problems that can affect it. There are many different Conditions Causing Colic (CCC’s) that affect each of these different regions. Some CCC’s are simple and often resolve on their own.  Examples are intestinal spasm or gas.  In fact, more than 60% of horses that experience abdominal pain will either resolve on their own or will resolve with basic medical treatment.  The majority of the remainder will respond to intensive medical treatment in a hospital setting.  Of all horses that show colic signs, only a small percentage will require colic surgery.  It is these horses that are the subject of this article. Your vet’s role is to do the diagnostics necessary to determine a cause for the colic and to determine whether it should be handled medically or surgically. SURGICAL EQUINE COLIC Horses that have a mechanical problem in their abdomen are often surgical cases, meaning that the problem can only be corrected with mechanical manipulation at surgery.  Examples of mechanical problems include: A large colon volvulus  – meaning that the large colon is twisted. A strangulation of the small intestine by a fatty tumor on a cord (known as a pedunculated lipoma). An impaction of the large colon, usually a build-up of feed material or sand. A foreign body blocking the small colon. There are countless other variations… For each of the above diagnoses, there is a specific prognosis and an estimated surgical cost.  For example, surgery for some large colon displacement usually has a better prognosis and is less costly than a small intestinal strangulation. One of the most important concepts to understand is that colic surgery is in itself “the ultimate diagnostic test.”  Until the surgeon actually explores the abdomen to see what is going on, they cannot give you a definite diagnosis, prognosis, or expected cost. How does the clinician know that your horse needs colic surgery? Horses that are presented to a hospital, after unsuccessful colic treatment in the field, are examined carefully to try to determine whether they can be treated medically or surgically.  Here are scenarios that would suggest that a horse needs colic surgery. A specific diagnosis is made and the best treatment is deemed to be surgery. In the absence of a definitive diagnosis, the horse is exhibiting severe and persistent pain, making medical treatment difficult and requiring repeated pain medication and sedation. The horse may not look that bad (especially if they have been given pain medication), but all of the diagnostic tests add up to a case that is better managed surgically. Medical management has not corrected the problem in an acceptable period of time.  No diagnosis has been made but the horse is still in pain and the only thing left to do is explore the abdomen surgically. The veterinarian who sees the horse in the field must make a quick determination as to whether or not this horse is a surgical candidate.  Perhaps the most important part of making that determination is asking you, the horse owner, about whether colic surgery is even an option.  In many cases, the only other option is euthanasia. YOUR DECISION Here are some points to consider when faced with this difficult decision: Diagnosis & Prognosis.  What does your veterinarian and the surgical veterinarian think is wrong with your horse?  How complicated will the surgery be, and what is the likely prognosis if all goes well during surgery?  What is the rate of recurrence of the condition?  Are you comfortable with all of the risks involved? Relative risk.  Colic surgery requires general anesthesia. Modern general anesthesia in horses is much safer today than it was 30 years ago, but there is still a small risk.  There are a variety of systems used today to assist horses in recovery from anesthesia, but even so, there is a small risk of injury during recovery. Cost.  Can you pay for colic surgery? Is your horse insured? If so, is there coverage for colic surgery?  Colic surgery is expensive because it is performed in an equine hospital that has adequate staff, training, equipment and experience to do the surgery correctly, and can handle the intense follow-up care necessary. Temperament.  Is your horse a good colic surgery candidate from a temperament standpoint? Temperament of a potential surgical candidate is important.  Some of the worst candidates are intense performance horses that simply cannot tolerate being locked in a stall for the weeks following surgery. Age and other conditions. Older horses and horses with other underlying diseases tend also not to be the best candidates for colic surgery. Travel & Convenience.  How far will you have to go for this service?  Will your horse survive the trip? Stress.  Colic surgery is not for every horse owner.  Intense colic surgery cases are stressful experiences for horse owners, especially if there are post-operative complications. I tell my clients that the post-operative period in some cases can be a roller coaster ride. SO YOU HAVE DECIDED TO PROCEED WITH COLIC SURGERY Assuming you have been fully advised and have decided to proceed with surgery, the team now prepares your horse for the surgery.  He stands in a brightly lit exam room with a team of people gathered around him.  Veterinary staff is rapidly clipping the hair from his abdomen.  Intravenous fluids pour into his vein through an IV catheter in his jugular vein, attached to a large fluid line that lead to grocery bag sized IV fluid bags hanging above his head.  Other staff is busy preparing the surgery room and anesthesia.  Your horse is given a variety of medications in preparation for the surgery.  Within minutes, he is taken into a small padded room where he is anesthetized and gently lowered to the floor. A large endotracheal tube is placed into his windpipe to keep his airway open during anesthesia. The now unconscious horse has large hobbles placed on his lower legs. These are hooked to a hoist and trolley, and he is transported upside down to the surgery room.  He is then placed on his back on a well-padded hydraulic surgery table. He is secured to the table with ropes. The anesthetist hooks up a large animal anesthesia machine and ventilator to the endotracheal tube.  They also set up the equipment that monitors his blood pressure and vital signs. The belly is carefully cleaned and sterilely prepared for surgery. Large drapes cover the whole horse, and serve to isolate the surgical area and keep it clean during surgery. A heavily gowned surgeon makes about a 15-inch incision on the lowest part of the belly.  The surgeon and his assistant then explore the abdomen (sometimes shoulder deep) to find the problem.  Most of this is done by feel, because many structures of the abdomen cannot be pulled out in plain view. Colic surgery is a very physical undertaking.  Heavy segments of intestine must be pulled out of the abdomen and emptied or repositioned.  Once the surgeon has made a diagnosis, he or she will usually want to discuss the problem with you.  If the problem is inoperable or the prognosis is poor, the decision may be made to discontinue the procedure and the horse may be euthanized on the surgery table.  You should be prepared to have this discussion. Once the specific problem is diagnosed, it must be repaired.  The treatment depends on the diagnosis, and could involve repositioning displaced intestine, removing damaged intestine, clearing a blockage of feed, sand, or a foreign object, or any other necessary procedure.  Surgical time ranges from 1 ½ to 4+ hours.  Once the surgeon is confident that the abdomen is free of other problems, the abdomen is closed meticulously with a several layers of suture material, one of which is the heavy holding layer through the strong connective tissue sheet of the body wall. The horse is then returned to the padded stall and assisted in recovery from anesthesia.  Once he is steady on his feet, he is moved to his stall. Once in the stall, the horse is often kept on intravenous fluids and monitored carefully. Most horses are on antibiotics and some sort of pain management. POST-OPERATIVE COMPLICATIONS Survival rates for many types of colic operations are high, but things can go wrong at any time during this process.  Very ill horses may have trouble surviving anesthesia.  Horses can be injured during recovery.  For horses with more severe conditions, the five days following surgery are a critical time and require intense medical treatment and monitoring as well as large volumes of intravenous fluids and other medications.  During the first few days, horses are often checked every 1-3 hours (day and night) and monitored carefully for any sign of a problem. The duration of intensive care depends on the condition that was corrected and many other factors.  Complications during this period include return to colic pain, abdominal infection, laminitis, colic recurrence, incision problems, and others.  For horses recovering normally, the intensity of medical care decreases after a few days and the horse is allowed to leave the hospital 5 to 7 days after the operation. HOME CARE Once home, horses must be confined for about 8 weeks in a small stall and hand walked several times per day.  A horse must be kept from moving at speed until the abdominal incision gains sufficient strength to take the weight of the intestines and organs in movement.  Diet may need to be modified during the period of stall confinement, and other specific treatment instructions may be given to you depending on the specifics of the case. The prognosis for horses after colic surgery depends on many factors. The most important of these is probably the diagnosis. Some conditions have a high recurrence rate. Studies have shown that a high percentage of horses can return to a performance career after colic surgery, performing at or above their level prior to surgery. Another recent study showed that older horses have a much better prognosis following colic surgery than previously thought. CONCLUSION The horse world is full of misconceptions about colic surgery.   It is true that 30 years ago, successful outcomes were rare.  Since then, though, there have been great strides made in equine surgical and anesthetic technique.  Today many conditions carry a very good prognosis. That said, it is important to always remember the following: It is possible to invest a large amount of money and hope in colic surgery and aftercare, only to find that the horse suffers from a fatal complication later. Survival to discharge is one thing. Long-term survival is another. Once you have embarked on the path of colic surgery, there is always the concern of “throwing good money after bad.”  If things are going poorly, you need to think about when you will stop. Once you have taken your horse to a referral center for colic surgery, the key is good communication with the equine surgeon.  He or she will inform you of the risks and prognosis, and help you to make the best decisions along the way. CONCLUSION My advice is to have a plan for each of your horses with respect to colic surgery, before being faced with having to make the decision. It is wise to learn as much as you can about the costs, risks and benefits of the colic surgery. Also, it may be wise to investigate the costs and benefits of equine health and mortality insurance. Once you are well informed, your final decision will still have to be made when you are faced with the crisis. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated APRIL 2014  Would you like to learn more about equine colic surgery on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:  Observation - Abdominal Pain, Colic Signs Observation - Recurrent Colic Episodes without a Diagnosis Diagnostic - Rectal Exam for Abdominal Disorders Diagnostic - Ultrasound, Trans-abdominal for Colic, Generally Diagnosis - Small Intestinal Strangulating Conditions Diagnosis - Colic, Simple Intestinal Gas or Spasm        
Colitis, Diarrhea & Intestinal Health in Adult Horses The equine digestive tract is a complex and fragile system that is easily disrupted.  The intestines (about 80 feet long in an average adult horse) digest and absorb feed, extract nutrients, absorb water, and eliminate waste.  One sign that the intestines are disturbed or otherwise stressed is the development of diarrhea.   The causes of equine diarrhea can range from mild to life threatening.  In adult horses, these causes include everything from mild stress to severe intestinal infection.  Given that the function of the intestine in adult horses differs from that in foals, this article only addresses the problem in adult horses. THE LARGE COLON Digesting, absorbing and utilizing the normally indigestible sugars in hay and other green plants would be impossible for horses without the action of microbes (bacteria and protozoa) in their specially adapted large colon.   Microbes break down these sugars into products that can be readily absorbed and used by horses.  The large colon is the car tire sized lower part of the intestine that contains a huge population of these microbes.  It is critical to the digestion and absorption of nutrients and water uptake.  These processes are interdependent and require a normally functioning flora (microbe population), and a healthy colon lining made up of cells that absorb water and nutrients, and functioning vessels to move fluid into the circulating blood. Diarrhea is an excess of water in the manure and is caused when anything disrupts the very specific balance of microbes in the colon or damages the colon lining or circulation.  When water is not absorbed in the colon, it is lost into the manure resulting in loose stool or diarrhea.  Serious diarrhea accounts for huge water loss, and can cause rapid loss of fluid from the circulatory system.  This leads to a vicious cycle of low blood pressure and reduced blood flow to vital organs (circulatory shock), which can quickly result in death if untreated. It is important to differentiate between acute (sudden) and chronic (long term) diarrhea.  Mild, acute diarrhea may be caused by stressful situations such as trailering.  This is a reflex caused by the nervous system.  Most horses produce normal manure soon after the stress is resolved.  In addition, rapid diet change alters bacterial populations resulting in diarrhea and usually improves as the intestinal balance shifts back to normal.  In severe cases, however, it can lead to colitis, a severe inflammation of the large colon. Chronic diarrhea in adult horses usually relates to a damaged colon wall and reduced uptake of water.  Horses with chronic parasite infestation, inflammation or tumors involving the colon wall often have chronic diarrhea.  These horses usually also have severe weight loss. Parasite infestation causes weight loss and diarrhea by causing damaging the intestinal wall and causing low-grade colitis. COLITIS Colitis is inflammation of the colon.  When the colon wall is irritated it loses function, thereby losing its ability to internally uptake water, and may actually dump fluid from the blood stream into the manure.  Colitis can be caused by a variety of problems, but often results from a disruption of the normal bacterial flora due to a rapid feed change.  A classic example of this is grain overload, which can cause entire populations of normally occurring microbes to die off and others to flourish.  This imbalance and direct damage to the colon from the acid products from the grain can lead to colitis, which results in diarrhea. Bacterial colitis is caused by overgrowth of undesirable organisms in the colon.  Overgrowth of organisms that normally live in the colon can take place, or a new organism may be introduced.  Often we do not know why these bacterial populations shift, but when they do, life threatening colitis and diarrhea can result.  Bacterial colitis is often caused by types of Salmonella and Clostridial organisms.  Understanding where these organisms come from or what causes them to multiply suddenly has proven to be difficult and is still not completely understood. Researchers have learned that some types of bacteria can be transmitted through contact with horses that are shedding the organism in their manure.  Some have been isolated from environmental sources like contaminated drinking water.  An important point is that these organisms appear when the normal flora of the gut is disrupted, especially by the use of certain antibiotics. Whether or not a horse becomes infected with these diseases depends their immunity, as related to their general health and the specific balance of microbes in their intestine.  Acute colitis is rare but occur more often under more crowded and stressful conditions.  There have been serious outbreaks of bacterial colitis in equine hospitals and breeding farms.   An important factor in these outbreaks is that most of the horses infected are sick or stressed and usually have been on antibiotics.  Antibiotics alter the normal bacterial populations and make horses more susceptible to overgrowth of these bacteria.   A less common cause of colitis in the Southwest (more common in the Northeast) is Potomac Horse Fever, caused by an organism that relies on a parasite in freshwater snails for its life cycle and transmission to horses. SAND COLIC Sand accumulation, so called “sand colic” also often causes diarrhea.  Horses accumulate sand accidentally as they eat hay off sandy ground or graze short stubble in a sandy pasture.  Diarrhea results from partial blockage of the colon, and irritation to the colon lining from large quantities of sand.  At its worst, a horse can accumulate more than 100 lbs of sand in their colon.  The critical factor determining a horse’s likelihood of getting sand impaction is whether or not the soil upon which horses are fed is sandy or not.  Fine clay soils are not likely to accumulate in the colon like sand.  See  Sand Accumulation in the Colon: A Common Cause of Equine Colic for more details. TREATMENT & PREVENTION Veterinary diagnostics for horses with diarrhea include a careful history and physical exam.  Laboratory tests on blood and manure are used depending on the case.  The veterinary treatment of diarrhea in horses depends on a properly diagnosed cause.  Stress induced watery manure, for example, may require little or no treatment.  Colitis, on the other hand, must be treated immediately and often requires hospitalization.  Types of treatments in these cases may include oral and intravenous fluid therapy, plasma, antibiotics, anti-inflammatories, and nursing care.  Unfortunately, severe colitis has a high rate of complications including laminitis, which can also be life threatening. Horse owners should observe the following precautions to reduce the likelihood of diarrhea and colitis in horses: Reduce stress and provide the most natural lifestyle possible with consistent turnout. Feed a staple of a good roughage source in the form of quality hay or pasture free of toxic weeds.  Use grain as a supplement, not as a staple. Avoid sudden changes in diet. Ensure access to fresh water at all times.  Avoid relying on stagnant or contaminated ponds, streams, or ditches. Maintain an appropriate parasite control program. Use antibiotics only when truly necessary and under the guidance of your veterinarian. Always communicate with your veterinarian immediately if you notice diarrhea. Horses suspected of having intestinal infection should always be isolated until your veterinarian can advise you. Prevention of sand accumulation involves determination of whether or not your soil type puts your horses at risk.  If your soil is sandy, you should take proactive steps to ensure that your horses do not accumulate sand. These steps include: Feed off the ground in mangers or tubs. Ensure that the spillage from these is not picked up from sand (lay down mats or other barrier under the tubs). Use psyllium as a preventative supplement, per your veterinarian's instructions. Horses grazing on sandy pasture should not be allowed to graze down to short stubble.  When they do, they are more likely to ingest sand. Diarrhea is an uncommon but potentially serious symptom in adult horses and is a sign of disrupted intestinal function. The observation of diarrhea in an adult horse should not be grounds for panic, but should prompt you to monitor the situation carefully and contact your veterinarian right away. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   Would you like to learn more about equine colitis and intestinal health on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:   Observation - Manure is Watery, Diarrhea (in Adult)   Diagnosis - Clostridial, Clostridium Colitis (in Adult)         
Common Veterinary Tests Used to Diagnose Conditions Causing Colic (CCC's) Your horse is showing signs of colic. You have asked us to provide emergency veterinary care, or your local veterinarian has referred you to us for additional diagnostic testing and treatment. We want to be clear about the value you get from the diagnostics and treatments we perform, as the costs add up quickly and we don’t want to surprise you with them. The purpose of this handout is to educate you about how we evaluate horses experiencing colic, and to describe some of the more common tests we use to identify the Condition(s) that are Causing the Colic – the CCC’s. If you have questions about the exam or any of the diagnostics performed, please feel free to ask. You can also find much more detailed information in Horse Side Vet Guide®, which is a constantly growing encyclopedia of equine health information that we created. The website is free - - and the mobile app is just $5. available on iTunes & Google Play.  Below we have included some links to HSVG, which contain more detailed information about each diagnostic. COSTS & FINANCIAL CONSTRAINTS Cost is only one of many factors we consider when assisting you in your decision-making. That said, it is very helpful to know if you want us to “do everything possible” or if you are faced with money constraints. We will recommend diagnostic tests that yield the most helpful information while striving to work within your budget. After all the diagnostics are performed, we will recommend various treatment options. Again, the question of cost will arise, and you need to be prepared for that conversation. Although less than 10% of all colic cases are surgical, you should be prepared to decide whether or not your horse is a candidate for surgery. See our related article Colic Surgery: What Horse Owners Should Know for more information. HISTORY If possible, we will ask you a series of questions about the horse. During this conversation we often gather important clues that help us determine why the horse is ill. This information is critical to our understanding of the disease processes that might be affecting the horse. Questions we might ask include: Management and feeding of the horse, including any recent changes. What specific signs of colic has your horse been demonstrating? For how long? Have you (or your referring vet) given your horse any medication? If so: what, how much and when? What is your past approach to preventative healthcare for your horse? Any recent vaccinations? Deworming? Dentistry? Farriery? Other treatments? What is your horse’s past medical history? Have they experienced colic before? If so, how recently? What do you do with your horse (pleasure, performance, pet)? Do your other horses appear ok? We may ask many other or different questions, depending on the circumstances… If you have additional information that you think may be helpful, be sure to tell us! Sometimes seemingly irrelevant information can turn out to be a valuable and relevant clue to the underlying cause. THE PHYSICAL “COLIC” EXAM We start with a careful physical exam tailored to the horse showing abdominal pain (colic).   How detailed an exam we do depends, in part, on the degree of pain the horse is experiencing. If the horse is in severe pain, our exam may be very brief because we are forced to provide pain relief and sedation to allow examination. Once these medications have been given, it can be harder to reach helpful conclusions from the exam results. We always consider the horse’s general health –including their age, body condition, attitude, coat and weight.  We take basic vital signs including temperature, pulse, respiratory rate and character, and we look at mucous membrane (gum) color, capillary refill time, pulse quality, intestinal motility, and the presence or absence of digital pulse. An examination of the mouth and teeth, or other areas of the body might also be important. Of particular importance in horses experiencing abdominal pain include: Pain level and duration, and our ability (or inability) to control the pain with various drugs. Cardiovascular status: including heart rate, gum color, pulse strength and capillary refill time. Rectal temperature can indicate the presence of absence of infection or intestinal damage. Intestinal motility (the presence or absence of normal intestinal movement.) The presence (or absence) of bloating (abdominal distention).  RESPONSE TO PAIN RELIEVERS [caption id="attachment_6954" align="alignleft" width="225"] Bute & banamine can be useful, but it is important to understand their limitations.[/caption] In some cases, you or your regular veterinarian will have already given your horse flunixin meglumine (Banamine®) or other medications. Keep in mind that pain-relieving medications may make your horse look better to you than he actually is. These drugs often mask the signs of pain, without solving the underlying condition. Once the pain medication wears off, the horse may return to showing signs of pain.  See Bute & Banamine: What Horse Owners Should Know. We consider the effects of previously administered drugs when we examine your horse, and we try to see past their expected effects. When we give pain medications, we expect to see a certain response. Specifically, we expect certain conditions causing colic (CCC’s) to be more or less responsive to pain medications. Consequently, how a particular horse responds to pain medication is one more clue about the Condition Causing Colic. Note: Most sedation drugs also cause slowdown of the normal movement of the intestine. This is generally not good, so we try to avoid giving sedatives whenever possible. PASSAGE OF NASOGASTRIC TUBE [caption id="attachment_7419" align="alignright" width="170"] The tube is placed through the nasal passage down the esophagus & into the stomach.[/caption] One of the first steps in diagnosing a horse in abdominal pain is to pass a nasogastric or stomach tube.  Horses have a small stomach, and our first job is to determine whether it is under pressure from backed up gas or fluid. What comes out of the stomach into the tube (gas, fluid or nothing) gives us clues to the nature and location of the intestinal problem. The long, flexible plastic tube is inserted through one of the nostrils, goes through the nasal passages, pharynx, and follows the esophagus into the stomach. In the average adult horse the distance from the nostril to the stomach is 4 to 5 feet. In passing a stomach tube, the veterinarian must be sure that the tube passes through the correct nasal passage, encouraging the horse to swallow the tube to begin passage into the esophagus, and then guides the tube through the tight valve into the stomach. When the tube enters the stomach there is usually a rush of gas and a typical fresh grass or hay smell. Of course the tube must not end up in the lungs. If fluid is pumped into the lungs, it will likely be fatal to the horse. Never try this procedure yourself! Passing a stomach tube is a common skill practiced in equine vet medicine, but smooth, easy stomach tubing IS AN ART that requires HORSEMANSHIP. Some horses tolerate the procedure well, while others resent it and could require a twitch.  How well the horse tolerates it generally relates to how well they are trained on the ground and the vet’s skill. Horses that normally get their way may resist this procedure strongly. Very rarely, a horse has insufficient training in hand to tolerate this and they require sedation in order to safely pass a tube.   In most cases though, a skilled vet can make the passage of a stomach tube look easy, usually without a twitch. Rarely, a horse experiences a bloody nose during or following this procedure.  This results from abrasion to delicate membranes in the nasal passages by the tube. It usually results from the horse struggling when the tube is being passed, but it can also result from the tube going in the wrong passage and hitting a particularly vascular “dead end nasal passage”. While a blood nose looks terrible and we hate it when it happens, keep in mind that even a bad nose-bleed is relatively minor hemorrhage for a horse, so it is usually not a problem. Passage of a nasogastric tube can be used diagnostically, or as part of a treatment regimen. As a Diagnostic Test: Nasogastric intubation helps determine the presence or absence of fluid or gas accumulation in the stomach. In a normal horse, there should be little fluid accumulation in the stomach. If there is significant fluid accumulation, it can mean that there is a blockage (either physical or functional) of the upper part of the intestinal tract (the small intestine), which is causing backup of fluid into the stomach.  We call this abnormal accumulation of fluid “reflux."  Knowing whether or not there is reflux is important diagnostic information. As a Treatment: To relieve overfilling of the stomach and intestine with reflux in cases where this is causing pain or contributing to the disease process. Or, to administer fluids and other medications into the stomach, when appropriate and when the stomach is not already full. RECTAL EXAM In a rectal exam, a veterinarian places a gloved, lubricated arm into the horse’s rectum in order to feel the anatomy of the back half to two-thirds of the abdomen.  The rectum is thin walled, and with careful examination, an experienced equine veterinarian can feel and evaluate many of the abdominal organs through it. Structures such as the left kidney (the only one of the kidneys we can reach), the large colon and other parts of the intestine, the inguinal rings, the bladder and parts of the reproductive system can be evaluated. A specific problem with the intestine or other organ is sometimes diagnosed with this exam. More often though, we are able to determine what GENERALLY is going on by feeling gas or fluid distension patterns or a specific segment of intestine in the wrong position in the abdomen.  Sometimes the rectal exam findings are completely normal, and this in itself is very helpful information. Most horses tolerate rectal exam pretty well, but in some cases we may need to sedate or twitch horses for this procedure for better relaxation of the horse and the rectum. A very rare, but potentially severe complication of rectal examination is tearing of the delicate rectal wall.  While this is a very uncommon complication, a severe rectal tear can be fatal.  It is important that you understand that there is a small risk associated with rectal exam. MANURE RELATED DIAGNOSTICS Tests for blood or protein in the manure may suggest bleeding or protein loss into the gastrointestinal tract. [caption id="attachment_7460" align="alignleft" width="300"] Sand Sediment Test in Glove[/caption] Sand accumulation is a common CCC in certain geographic areas. A sand sediment test is often performed to indicate the presence of sand in the manure, a potentially important finding. But a negative sand sediment test does not absolutely rule out the presence of sand in the GI tract. Although often performed in horses showing colic signs, Fecal Egg Counts may or may not be useful in determining whether parasitism is the CCC. Fecal Egg Counts are an indicator of shedding of parasite eggs but not necessarily parasitic disease. ABDOMINAL ULTRASOUND [caption id="attachment_7418" align="alignright" width="300"] Ultrasound probe is placed on the left abdominal wall. Image courtesy of The Glass Horse.[/caption] In most hospital and referral cases, we use ultrasound of the abdomen as an additional diagnostic tool.  Abdominal ultrasound may be used either trans-rectally (through the rectum) or through the abdominal wall from the skin. In colic cases, it is mostly performed through the abdominal wall (trans-abdominal). The ultrasound emits sound waves that pass through tissue at various speeds depending on specific tissue characteristics.  The sound waves bounce back to the transducer and a digital picture is produced by computer analysis of the returning sound waves. Ultrasound is a wonderful tool for gathering more information about the equine abdomen. It can give additional valuable information regarding the position and state of various parts of the intestine. It is also used for evaluation of the tissue characteristics of liver, spleen and other abdominal organs. One limitation of ultrasound is its inability to penetrate gas-filled structures or solid feed. Another limitation is the relatively shallow penetration of the sound waves- only 6-12” at the most. How deep we can image depends upon the ultrasound machine and probe. [caption id="attachment_7414" align="alignleft" width="300"] Ultrasound image of the left kidney & spleen. Image courtesy of The Glass Horse.[/caption] Like many other diagnostics, the quality of the information is only as good as the skill of the veterinarian performing the procedure.   BLOOD WORK, LAB TESTS & CBC Serum chemistry and hematology tests are performed using sophisticated and expensive equipment in our laboratory.  We have chosen to purchase this equipment so that we can offer you the very best care for your horse. The in-house lab gives us important information to allow us to make decisions quickly, rather than having to send samples away and wait for days for a result.  Sometimes we do choose to send blood or samples away to a reference laboratory to have the testing done there.  This is usually because the lab offers particular tests that we cannot perform in our hospital. A complete blood count (CBC) includes a count of red blood cells and several populations of white blood cells.  A complete blood count gives valuable information about the health of the horse, its hydration status and characteristics of the disease process.  A white blood cell count is especially helpful in supporting a diagnosis of bacterial infection or can suggest intestinal damage or endotoxemia.  This test is performed within 10 minutes, in our hospital. BLOOD CHEMISTRY The blood chemistry is a battery of individual blood tests for levels of about 20 enzymes and molecules within the blood.  Serum enzyme level increases can indicate damage to specific organs. An example of a serum enzyme is LDH (lactate dehydrogenase).  This enzyme is found only in liver and muscle cells.  Large elevations in this enzyme can mean that either liver or muscle cells have been damaged and their enzymes released into the blood. We use the rest of the exam and other blood work findings to interpret the significance of individual test results.  Examples of other levels measured are glucose (blood sugar), creatinine (an indicator of kidney function), and many others. Total protein and albumin can be indicators of hydration status. A decrease in these can indicate loss of protein through a damaged intestinal wall. Electrolyte values say something about the general health and hydration status of the horse and can also provide clues about needed resuscitation and treatment. BLOOD & ABDOMINAL FLUID LACTATE LEVELS Lactate measurement can be a helpful diagnostic test for horses showing signs of colic. Lactate (lactic acid) is produced by tissues that are deprived of oxygen for any reason. In horses showing colic signs, high lactate levels can be associated with severe dehydration, shock. Blood Lactate also rises when segments of intestine are damaged or have poor blood supply. We perform lactate analysis on blood and abdominal fluid. Each provides useful information. The difference between blood and abdominal fluid lactate levels can also be helpful. Sometimes we repeat this test over time to monitor the change in lactates. Changing levels of plasma and peritoneal lactate can indicate whether a case is improving or worsening with treatment. [caption id="attachment_7425" align="alignleft" width="300"] A belly tap is the sampling of fluid that bathes the abdominal organs. A sterile needle is used to collect this fluid.[/caption] ABDOMINOCENTESIS  a/k/a BELLY TAP An important and common test used in cases of abdominal illness in horses is abdominocentesis, commonly known as “belly tap.” This involves the collection of a sample of the free fluid from the abdominal cavity.  This fluid bathes the outside of the intestine and abdominal organs. Changes in this fluid, both the appearance of the fluid and the laboratory results, give critical information regarding the health of the abdominal organs, especially the intestine. Certain changes in the fluid suggest damage to intestine and so can help determine the need for colic surgery or intensive care and can provide information about prognosis. The Belly Tap procedure involves clipping a specific site on the lower belly.  This site is then carefully disinfected.  A needle is introduced carefully into the abdomen, using special care not to puncture intestine or other organs. The needle is maneuvered until fluid is encountered, and a small sample of this is caught in 2 types of tubes. In our hospital, we are successful at obtaining fluid in about 70% of cases by using this technique.  In cases in which we are unsuccessful, we resort to using a larger, blunt tube and a different, slightly more complicated procedure. We perform belly tap after ultrasound when possible. Ultrasound allows us to locate small pockets of fluid within the abdomen. Unfortunately, sometimes it is just not possible to collect abdominal fluid.  This is usually because there is very little fluid in the abdomen.  In other cases, clots of inflammatory material or feed can block the needle or tube. [caption id="attachment_7424" align="alignleft" width="137"] Normal abdominal fluid is clear and pale straw/yellow colored.[/caption] Once we collect abdominal fluid, we analyze it in our lab for certain cell and fluid parameters.  We commonly measure total protein. Total protein in normal abdominal fluid should be very low (less than 1.0 g/dl).  Total protein over 2.5 generally indicates a severe disease process going on in the abdomen. As intestine is damaged, the intestinal vessels become leaky and allow protein to escape from these tissues and enter the fluid.  We then see an increase in total protein in the fluid. Changes in abdominal fluid characteristics can be useful in determining progression of the disease. [caption id="attachment_7417" align="alignright" width="168"] Cloudy yellow abdominal fluid indicates the presence of inflammatory cells.[/caption] The risk of this procedure is usually very low. The risk is a little greater in foals but still not great. The main risk is puncture of intestine, leading to leakage of bacteria-laden intestinal contents, causing inflammation and/or infection of the abdomen. [caption id="attachment_7422" align="alignright" width="124"] Reddish-orange abdominal fluid indicates intestinal damage.[/caption] Limitations on this test include lack of fluid, inability to obtain fluid, and contamination of the fluid by prior attempts and abdominal decompression, feed or blood. ABDOMINAL RADIOGRAPHS Obtaining abdominal radiographs of a full-sized horse is only possible using very powerful x-ray generators. The mass of the abdomen is difficult to penetrate. For this reason, this diagnostic test is usually only performed at large referral hospitals and vet schools that have this equipment. Abdominal radiograph’s greatest value is in visualizing enteroliths (intestinal stones) and sand accumulation. [caption id="attachment_7459" align="alignleft" width="300"] Abdominal Radiograph with Enterolith (Intestinal Stone)[/caption] Abdominal x-ray may be very valuable for smaller ponies and foals and may give additional diagnostic information in those equines, which may be impossible to perform rectal exam on. CONCLUSION As we gather all of the information from the diagnostics above (and possibly other diagnostics that are tailored to a particular circumstance), we put it together to begin to identify the CCC - the Condition Causing Colic. The presumed diagnosis of the CCC, coupled with the systemic health and pain level of the horse determines the best treatment options.  Which treatment options you choose depends on many factors, including economic constraints. Keep in mind that all of this information only gives us a rough picture of what is going on in the abdomen. Hopefully it can provide us a good enough idea that we can select effective treatment. If you have any questions as we work, please do not hesitate to ask.  In emergency circumstances, we work very quickly to gather this information and present it to you for discussion.  Sometimes this can be a confusing process and we want you to fully understand what is going on with your horse from the beginning, so that you can make the right choices for you and your horse. By Douglas O. Thal DVM Dipl. ABVP, Board Certified in Equine Practice of Thal Equine LLC Last Updated September 2015
Cushing's Disease / Syndrome - PPID & EMS: What Horse Owners Should Know Horse owners are often unaware of problems that affect their horse’s health in less obvious ways.  Endocrine diseases are classic examples.  The endocrine system is the hormonal, regulatory system of the body.  Endocrine glands are tiny organs that secrete hormones and substances into the bloodstream as necessary to maintain control of body systems. There continues to be great confusion in the horse world surrounding endocrine diseases.  If anything, this has been made worse by the recent recognition and re-naming of some of the syndromes.  Disease names are used frequently but often incorrectly in the equine world.  This article explains the basic concepts of endocrine (hormonal) function and disease, and discusses the two most common endocrine diseases in horses: •  Equine Cushing’s Disease/Syndrome  - Also known as Pituitary Pars Intermedia Dysfunction- or PPID •  Peripheral Cushing's Disease/Syndrome - Also known as Equine Metabolic Syndrome - or EMS PITUITARY PARS INTERMEDIA DYSFUNCTION - PPID It is important for horse owners to understand that the equine body’s regulatory systems are complex. To understand PPID, you first have to understand the concept of how the endocrine system works.  This system is based on glands communicating with other glands, which then communicate with organs, all through signals (hormones) sent through the bloodstream. The system of pituitary-adrenal gland communication is just one example of how this works.  Abnormal function of this system is responsible for PPID. In a normal horse, there is intricate communication between the pituitary gland, located at the base of the brain, and a neighboring part of the brain, the hypothalamus.  The hypothalamus reads conditions in the blood, and based on this, sends a chemical signal to the pituitary gland to release precise amounts of certain substances into the bloodstream.  The levels of these substances in the blood then have direct effects on the adrenal gland located near the kidney, causing it to release cortisol, a steroid hormone very involved in most aspects of normal body function, into the bloodstream.  Cortisol then affects organs and body systems in its many vital ways. It is an overgrowth of part of the pituitary gland that causes PPID.  The cause of this overgrowth is still not entirely clear. This overgrown gland also is overactive in secreting hormones.  The excessive hormone levels in the blood then cause the adrenal gland to over-produce cortisol.  Cortisol and other overproduced adrenal hormones then cause the effects on hair coat, feet, musculature and other body changes that we see as the classic signs of PPID. The most important sign of PPID is laminitis.  How cortisol and other products of the overactive adrenal gland cause laminitis is still not entirely understood.  PPID is the reason many old ponies have chronic laminitis and badly misshapen hooves.  When an old horse suddenly has a bout of laminitis for no apparent reason, one of the first things I consider is PPID.  Laminitis, as we have discussed in previous articles, is a life threatening degeneration of the attachments of the hoof wall to the underlying tissues.  Perhaps the most important reason to recognize and understand PPID is to control the problem before it results in laminitis. Horses with PPID often have changes in the appearance of the hair coat.  The classic change is a long, curly coat that is often retained through the summer. Sometimes the only area where coat is retained is on the legs or in patches on the body.  Other signs of PPID are recurrent infections (sole abscess, respiratory infection, skin infections), excessive urination and drinking, muscle wasting over the top-line, and a pot-bellied appearance. Many horses affected by this problem are lethargic but usually maintain a good appetite.  Mares with this and other hormonal disease may be difficult to breed.  The disease is found in all breeds but is more common in the pony breeds and Morgan horses.  Diagnosis of PPID is based on a veterinary examination, history, and several specific blood tests for hormone levels. PPID is a very significant and common disease of old horses, and every horse owner should be aware of its signs.  In the past 10 years, better treatment and management methods have been developed.  The key is awareness and recognition.  Treatment involves changes in management, special attention to good basic care, and the use of specific medications that control the production of hormones.  This approach is practical, affordable and is usually very effective, allowing horses to lead relatively normal lives.  Failure to recognize the problem leads to other problems like laminitis and recurrent infection, which ultimately can lead to death. EQUINE METABOLIC SYNDROME - EMS Our understanding of diseases of the endocrine system has increased greatly.  For example, when I started equine veterinary practice in 1993, a certain type of  overweight horse was thought to be hypothyroid (have a low thyroid hormone level).  This classic, so-called “hypothyroid” horse has lots of fat over the top-line and around the tail-head, and has a thick, cresty neck.  Horses fitting this description are common and are sometimes just referred to as “easy keepers.”  A minimal amount of feed keeps these horses fat.  These horses have a high incidence of laminitis.  In the past, veterinarians treated many of these horses with thyroid hormone supplements, reduced feed, and exercise, and many did improve. The syndrome is now referred to as Equine Metabolic Syndrome, and we have learned that these horses are usually not hypothyroid.  As happens in overweight people, the excess fat causes a cycle of more health problems by causing the body to be resistant to the effects of insulin.  This leads to high blood sugar and fat, and most importantly for the horse, can lead to laminitis.  Laminitis in these horses is usually low-grade and chronic, and can sometimes be very resistant to treatment.  Diagnosis of EMS is fairly simple and cost effective, and is primarily by history, examination, and the measurement of blood insulin levels. Treatment involves decreasing feed intake (especially grain) and increasing exercise levels.  Certain feed supplements and drugs aimed at improving the function of insulin are sometimes used, but are currently not proven to be effective.  Once again, the key point is to recognize that this syndrome exists, that it can be diagnosed relatively easily, and most importantly, that it can be treated simply. CONCLUSION As a horse owner, it is important to be aware of the common endocrine diseases PPID and EMS, and understand that they usually manifest in subtle ways.  Changes in a horse’s appearance that are caused by these diseases are often missed, and mistaken for normal. By being on the lookout for the signs of these diseases, there is an opportunity for diagnosis and treatment, and in so doing, an opportunity to improve the quality of life for your horse.  If your horses are showing even subtle signs of either of these diseases, contact your veterinarian promptly for the best diagnosis and treatment options. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Deciding When to Use "Risk-Based" Vaccines Vaccination is one of the most practical and cost-effective means for reducing infectious disease incidence in horses. There are dozens of equine vaccines made by various pharmaceutical companies and for a variety of equine diseases. Vaccine types and availability change frequently. These factors and many others make the question of how to vaccinate horses a confusing one. One might be tempted to just vaccinate for every disease, but vaccination does have a cost which must be balanced with predicted benefit. How should a horse owner or manager decide which vaccines to give their horses, and on what schedule?   In the case of the four “core vaccines” recommended by the AAEP, the decision is easy. All horses in North America should receive the vaccine once annually, in the spring.  Deciding whether or not to use the other, so called “risk-based vaccines” is not as easy. The decisions should be based on a balance between the benefits and costs of vaccinating for that particular disease, versus the risk in not vaccinating. This balance depends upon a host of factors specific to your region, your horses, the vaccine in question, and your management. Your veterinarian is the one equipped to help you determine the factors to consider in your specific situation, and to formulate an effective and reasonable vaccination plan for all your horses.  FUNDAMENTALS Infectious disease in horses is caused mostly by bacterial and viral organisms. These organisms, called “infectious agents” are transmitted to horses in many different ways, specific to the agent. Examples of modes of transmission for an agent include direct contact between horses, transmission by biting flies, contact with contaminated equipment, and many others. Whether or not a horse becomes infected in a given situation depends on a balance of several factors including the horse’s susceptibility to the disease, the characteristics of the infectious agent, and the dose that it receives of the infecting organism.  Vaccination causes the body to produce antibodies against a specific infectious agent. Antibodies are proteins, which bind directly to the agent and help the body rid itself of it.  Vaccination is an effective and convenient way to boost immunity against a specific agent. That said, prevention of infectious disease involves far more than just vaccination. It involves keeping horses in excellent general health and reducing exposure to infectious disease agents. THE AAEP'S "CORE" VACCINES The American Association of Equine Practitioners (AAEP) regularly publishes updated equine vaccination guidelines for use by horse owners and veterinarians. The AAEP’s “Core Vaccines” are recommended for every horse in North America. Vaccines selected as “core” possess one or more of the following attributes: They should protect from diseases with potential public health significance. (The disease has potential to infect humans or other animals.) They should protect from diseases that are established in a region. They are required by law. They should protect against diseases which are virulent/highly infectious and/or pose a risk of severe disease. The core vaccines must also have proven effectiveness. The AAEP Vaccination Guidelines refer to core vaccines as “having clearly demonstrated effectiveness and safety, and thus exhibiting a high enough level of patient benefit and low enough level of risk to justify their use in the majority of patients.”The core vaccines on this list currently include West Nile Virus, Eastern and Western Equine Encephalitis, Tetanus and more recently, Rabies.2 "RISK-BASED" VACCINES Risk-Based Vaccines are those recommended in specific circumstances, when the risk of acquiring the disease in question is great enough that it exceeds any disadvantage of using the vaccine. The use of risk-based vaccinations may vary regionally, from population to population within an area, or between individual horses within a given population.2 The choice for when to use these vaccines should be made jointly, by you and your local veterinarian. Your veterinarian knows the status of regional diseases of concern.  They know about new vaccines and pertinent state and federal regulations. When provided with information about the history, management, and goals for each of your horses, they can help you formulate a customized vaccination plan. So why not just vaccinate every horse with every vaccine? Vaccines are usually not very expensive, but cost can still be a factor for many of today’s horse owners, especially those with larger numbers of horses to vaccinate. In addition, and however small the risk, there is always a possibility of adverse vaccination reaction. The risk may increase as more vaccines are used simultaneously.  While most of these reactions are minor, they occasionally can be life threatening. For the purposes of this article, the Risk-Based Vaccines include vaccines for Strangles, Influenza EHV-4/1, Potomac Horse Fever, Rotavirus, Botulism, and Anthrax. STRANGLES Strangles is a respiratory disease caused by an abscess forming bacteria, Streptococcus equi. The classic sign of strangles is abscess formation behind and under the jaw. The name “Strangles” comes from these large swellings around the throat, which rarely are severe enough to cause difficulty in swallowing and breathing. Affected horses are often depressed and lose their appetites. The disease classically starts with throat or under-jaw swelling, nasal discharge, fever and cough. The swellings abscess, and ultimately break open and drain yellow pus. Strangles is common and is highly contagious to at-risk horses. It is easily transmitted by contact with nasal secretions and abscess drainage containing the organism. Infectious material can be transmitted on the hands of handlers, on shared tack and equipment, and through shared water sources. Vaccination has proven difficult for this disease. The problems with all of the Strangles vaccines have been relatively high adverse reaction rates and limited effectiveness. The most commonly used vaccine is a modified-live intranasal vaccine. It is considered a somewhat effective vaccine but has been faulted for having a higher-than-acceptable adverse reaction rate. It can actually cause a form of strangles in a very small percentage of vaccinated horses. The vaccine can be inoculated into the tissues at other vaccination sites, where it can cause abscess formation. It can cause other side effects as well. Strangles immunization is usually recommended when the risk of infection outweighs the risk of side effects from the vaccine. A critical part of reducing strangles incidence is taking steps to reduce exposure of horses to the organism. Recommended management includes quarantine of any new horse before introduction into a group, and immediate quarantine of any horses showing signs of the disease. INFLUENZA Influenza virus is common in horses. Typical clinical signs include high fever, cough and nasal discharge. This virus is highly contagious and spreads rapidly, expelled by coughing horses and able to infect other horses up to 30 feet away. As with all influenza viruses, the equine influenza virus is constantly changing its form, making it difficult to make a vaccine which contains the most current version of the virus. Horses in contact with others (show and performance horses and horses boarded at stables) are at greater risk for the disease. The usual recommendation is to vaccinate these horses at least twice annually. Vaccination may not be needed for isolated horses. A common recommendation is to vaccinate for this disease using one of several recently developed vaccines which cover the more current virus strains.1,2  The intranasal vaccine has shown good effectiveness and is very safe but several of the newer intramuscular vaccines are also considered effective.1,2  BOTULISM Botulism is a disease caused by potent toxins produced by the soil-living bacteria, Clostridium botulinum.  In horses, this disease takes several forms, involving different types of toxins; most commonly toxin types B and C. Botulinum toxins block transmission of nerve impulses, resulting in signs of weakness progressing toward complete paralysis and death. There are several syndromes seen in horses which have very different origins. The toxin can be created in the digestive tract of foals that have ingested the organism, be liberated into the bloodstream from wounds where the organism has grown, and be ingested by horses in fermented feed or feed containing animal carcasses.1 The only approved Botulism vaccine is against the Type B toxin. Type B is associated with the Shaker Foal Syndrome, seen relatively commonly in foals in Kentucky and in the mid-Atlantic states. It makes sense to use this vaccine in this geographic region and otherwise as directed by your veterinarian. There are no licensed vaccines available for preventing botulism due to Cl. botulinum type C or the other toxin types.1,2 The Type B Vaccine does not protect against Type C disease. Thus, routine vaccination against Clostridium botulinum type C is not currently practiced.2 EQUINE HERPES VIRUS (EHV-4/1) Also known as rhino or rhinopneumonitis, these are several related viruses that can cause respiratory, neurologic signs, or abortion in horses.  The most common of these are EHV-1 and EHV-4. In their chapter on infectious disease in the 4rth edition of Smith’s Large Animal Internal Medicine, Drs. David Wilson and Nicola Pusterla state: “EHV-1 and EHV-4 are spread by direct and indirect (fomite) contact with nasal secretions, by aerosolized secretions from infected coughing horses, and, in the case of EHV-1, by aborted fetuses, fetal fluids and placentae associated with abortions.” One unique characteristic of the EHV’s is that they can lay dormant and undetected in infected horses and then can cause signs of disease when immunity decreases due to stress or other factors.1,2  This makes control a challenge and explains how the disease can crop up in closed herds of horses.2 Vaccination against EHV’s has historically been problematic. In general, vaccination does not prevent infection but may reduce signs of disease and shedding of virus.  Certain EHV-4/1 vaccines are considered helpful at reducing signs of respiratory disease.2 These should be given at least twice annually to all horses that will be in contact with others, especially show horses and those that travel intensively. Unfortunately, vaccination does not prevent the neurologic form of EHV-1. It may, however, reduce the spread of EHV-1 generally by reducing shedding of the virus by infected horses, thus reducing overall neurologic disease incidence in a group of horses.2 Pregnant mares should be vaccinated as directed with a vaccine licensed to protect against the abortive form of the disease. Wilson and Pusterla state that “mares should be vaccinated during the 5th, 7th and 9th months of gestation, although some vets also recommend a dose during the third month.” Reduced shedding and spread is enough reason to vaccinate horses against the EHV’s, even if direct protection against the signs of disease is questionable. The benefit of giving equine herpes vaccine is generally less for older and more isolated horses. 2 EQUINE VIRAL ARTERITIS (EVA) This is a viral respiratory disease caused by the Equine Arteritis Virus (EAV). It is transmitted either through breeding or transmission from coughing horses. Importantly, this virus is commonly spread in cooled and even frozen equine semen.  While typically not life-threatening to otherwise healthy adult horses, EAV can cause abortion in pregnant mares and rarely death in young foals. It causes a long-term carrier state in breeding stallions in which they show no signs of disease but harbor the virus and transmit it in their semen.2   Signs of active disease are similar to other respiratory viruses, so diagnosis requires laboratory confirmation. The indications for vaccination against EVA have been: To protect stallions against infection and subsequent development of the carrier state. To protect mares before they are bred with EAV-infective semen. To prevent outbreaks in non-breeding populations of horses. Using available laboratory methods, it is not possible to differentiate vaccine induced antibodies from those due to natural infection. Thus, vaccination can confuse testing and cause a vaccinated horse to be treated from a regulatory standpoint as though it is infected.1,2 Commercial breeders should familiarize themselves with this disease and their state regulations related to it. In planning a vaccination program against EVA, it is important to consult with state and/or federal animal health officials to ensure that the proposed program is in compliance with the state's control program for EVA, if one exists. 2 ROTAVIRAL DIARRHEA Equine Rotavirus is a major contagious cause of foal diarrhea and has been documented to cause 50% or more of foal diarrhea cases in some areas.2   Mortality usually is low but many foals can be affected on a premise. Rotavirus is transmitted when foals ingest feces containing the organism.1,2   For this reason, strict quarantine of diarrheic foals is important to prevent spread to healthy foals. Vaccination of pregnant mares several times during pregnancy results in an increase in antibodies to the virus in colostrum (first milk). This immunity is passed on to the foal when it nurses, helping to prevent the disease.2   Field trials have demonstrated immunity in foals from vaccinated mares. There is probably less benefit in vaccinating the young foal iself.2 This vaccine is recommended on breeding farms, especially in regions where the disease is more common, and those that have had prior outbreaks of the disease.1,2 POTOMAC HORSE FEVER The organism that causes Potomac Horse Fever (Equine Monocytic Ehrlichiosis) is called Neorickettsia risticii. The disease manifests in horses as life-threatening diarrhea. PHF is more common in specific geographic areas, although it has now been diagnosed in many states and some foreign countries.2 Wilson and Pusterla state: “PHF is seasonal, occurring between late spring and early fall in temperate areas, with most cases in July, August and September at the onset of hot weather.” The agent is associated with water, and relies on a complex life cycle involving snails and aquatic insects. There is disagreement in the veterinary literature about the effectiveness of the available vaccines.1,2 A reasonable approach is to vaccinate in geographic areas where the risk is higher. The vaccine is considered fairly safe, and given frequently (4-6 month intervals), might help protect against disease.2 ANTHRAX Anthrax is a rapidly fatal blood disease caused by the organism Bacillus anthracis. Anthrax is typically only found in certain geographic areas with moist alkaline soil, which favors the organism. The vaccine is thought to be effective but can cause mild to severe vaccination reaction.2 Because of this, the vaccine is recommended only in the regions where risk of infection outweighs the risk of vaccination.1,2 CONCLUSION There is detailed information available on the web today concerning the science behind the mentioned diseases and the “risk based vaccines” that protect against them. There are many conflicting opinions, and even conflicting scientific research. While it is a good thing for horse owners to educate themselves about equine health topics, the factors involved here are complicated and can be confusing. This is a prime example of an equine health question that is best discussed with your own veterinarian, who is trained to interpret the scientific research and apply that interpretation to your individual horses and your specific needs.  REFERENCES Wilson WD, Pusterla N. Equine Vaccination and Infectious Disease Control, in Smith, B.P., ed, Large Animal Internal Medicine, 4th edition, pp. 1557-1587, 2009. AAEP Vaccination Guidelines for Risk-Based Vaccines. Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCRevised March 2013   
Equine Colic (Abdominal Pain): Part 1 It always surprises me when an experienced horse person asks me how I treat “colic.” That question is akin to asking a physician how they treat a “limp.” Equine colic is simply abdominal pain. Signs of equine colic are what we see - a horse’s behavior when it is experiencing abdominal pain.  Like a limp, colic can be caused by any of a large number of conditions (diagnoses). The key question we (vets and horse owners) must always ask is: What is the condition (diagnosis) that is causing the colic? The answer provides the information needed to determine how it should be treated. The term “colic” tends to cause confusion and panic among horse owners. There are many misconceptions and oversimplified statements about colic in horses. Examples that I hear frequently: Horses colic when the barometric pressure drops. If you keep a horse from rolling, he can’t twist his intestine. Putting a colicy horse in a trailer and driving around will “fix” him. If a colicy horse passes manure, they are getting better. Too often, I see the results of this flawed logic, which leads to delayed treatment and sometimes death. THE EQUINE GASTROINTESTINAL TRACT Since intestinal problems are so common in horses, it’s important for every horse person to know something about colic, and the basics of equine intestinal health. The equine gastrointestinal tract is unique in is its ability to utilize cellulose and other structural carbohydrates (the fibrous part of grass that is poorly digestible). The process of breaking down this carbohydrate into useable nutrition is called fermentation, which requires a specialized and complicated intestinal tract. Fermentation produces large quantities of gas and requires a complex ecology of microbes. This sophisticated system has worked well for wild horses for millions of years, but does not function as well for our stabled horses that are sedentary and fed 2 meals per day. A TRIP DOWN THE EQUINE GASTROINTESTINAL TRACT From the mouth, feed travels through the esophagus to a small, 3-5 gallon stomach, and then moves into a narrow, slick and slithering, 70-foot long hose - the small intestine. From here, the partially digested feed moves into a 3-foot long, sock-shaped, 5 - 7 gallon cecum.  The cecum mixes and ferments feed, absorbs water, and empties into a truck tire sized (tractor tire sized in some horses), double horseshoe shaped large colon with a narrow, hairpin turn.  The large colon is the “fermentation vat” where roughage is broken down into nutrients and absorbed. After leaving the large colon, manure moves into the 10-foot long small colon, where fecal balls are formed. The manure finally exits at the rectum and anus. SIGNS OF COLIC Horses are very sensitive to abdominal pain and demonstrate it differently than other animals. Signs of abdominal pain in horses range from mild to severe and include: lack of appetite, lethargy, seeming “not quite right”, lip curling, teeth grinding, looking at the side, stretching, pawing, kicking at the belly, lying down, rolling, and many others. CONDITIONS CAUSING COLIC - CCC'S Colic signs may result from disturbances that occur anywhere along the gastrointestinal tract, or even from problems with other abdominal organs like the kidney or liver. Intestinal pain can even be confused with pain coming from other areas of the body (examples include muscular pain and chest pain). Examples of conditions causing colic – lets call them CCC’s for short – can be broken down by the intestinal region that is being affected. For example, the stomach can develop ulcers or an impaction of feed material. The small intestine can be affected by something simple like spasm, or something serious like a twist. The large colon may be affected by simple gas, blocked by a stone or strangled by a twist. Any of these regions can be affected by inflammatory disorders or bacterial infections. These are just a few of many examples of problems causing colic. As a horse owner watching a horse showing signs of colic, you truly have no idea of the condition that is causing it. What exactly causes pain in horses experiencing colic? Pain arises from a CCC through at least one of the following ways: Tension on attachments of the intestine to the body wall (mesentery). Over-filling (distension) or muscular spasm of part of the intestine. Example: gas accumulation, spasmodic colic. Irritation to the inner surface of intestine.  Example: gastric ulcers, blister beetle toxicity. Loss of blood supply to a segment of intestine. Examples include large colon volvulus and thromboembolic colic. BREAKING THE PAIN CYCLE Many horses showing signs of colic resolve quickly on their own or in response to a pain-killer like Banamine®. It helps to use a human illustration: When you double over because your belly hurts, most of the time it’s just because you have some gas pain and not because you have appendicitis, but an observer that sees you in pain might not know that. The majority of people who experience a bout of intestinal pain will get over it by just suffering through it or with some simple medication. So, too, do many horses. Of 100 horses that we notice showing signs of colic, 60-70 will recover if we simply give the horse a little time, or a shot of Banamine® (flunixin meglumine - a potent anti-inflammatory and pain reliever). But it is critical for us to understand what we are doing when we give Banamine®. We are taking away pain. If the condition causing the colic pain happens to be minor, then it will likely resolve on its own. If the condition is more severe, we may make the horse appear improved for a time, but we are probably delaying proper diagnosis and treatment, and this could cost the horse its life.  See Bute & Banamine™: What Horse Owners Should Know for more details. Once a horse is in colic pain (from any condition) there is a sequence of events that tends to worsen the problem. In a healthy horse, normal movement of the gut propels food, fluid and gas down the tract. Blockage of this normal movement from any cause leads to gas and fluid backup, stretch on the intestinal wall, and pain. Pain causes the nervous system to shut down normal intestinal movement. Shutdown of the gut leads to more gas and fluid accumulation, which leads to more stretch on the gut wall, and more pain, and the cycle continues and worsens. If this cycle is broken by appropriate treatment, including pain relief, there is a better chance of the problem resolving. This is why it is important to start treatment early. This also assumes that the condition is a “simple” cause of colic and not a mechanical obstruction. If the problem is a true mechanical obstruction like a displaced, twisted or impacted segment of intestine, it will not resolve with conservative treatment or time. Instead it may require colic surgery or intensive medical veterinary care. It is impossible for an observer of horse in colic pain to distinguish between the less serious and the more serious CCC’s. More severe pain and longer lasting pain is more likely to be caused by a more serious condition, but this is not always the case. An experienced veterinarian can often quickly identify the CCC based on the results of a history, physical examination, various diagnostics, and intuition. Early treatment of horses with more serious problems may be the difference between life and death. Quick and correct diagnosis leads to quick and correct treatment. COLIC OCCURENCE CCC’s are common. Roughly 5%- 10% of domestic, stabled horses will experience an episode of colic in a given year. CCC’s affect all groups and breeds of horses in all geographic locations. Simple intestinal spasm is common everywhere, but certain types of CCC’s are more prevalent in different geographic areas. Specific conditions are also seen more commonly in specific breeds, ages and types of horses. For example, certain large colon displacements are more common in large warmblood-type breeds. Large colon volvulus (twist) is very common in post-foaling Quarter Horse and Thoroughbred broodmares. Generally, the incidence of CCC’s is higher in stabled versus pastured horses, and more commonly arise in horses that are fed a high grain to forage (hay or grass) ratio. In Part 2 of this discussion on colic, I discuss some of the CCC’s in colic in greater detail, your role when your horse has colic, your veterinarian’s role in coming to a diagnosis and instituting proper treatment, and preventative measures you can take to reduce the likelihood of colic in your horses. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated April 2013Recently reprinted in Horse Around New Mexico, May/June 2013  
Equine Colic (Abdominal Pain): Part 2 In Part 1 of this article, I discussed how colic is not a disease but a group of signs shown by a horse experiencing abdominal pain. The signs can range in severity from a subtle reduction in appetite to violent rolling or thrashing. I explained that abdominal pain (colic) could be caused by any number of conditions (“Conditions Causing Colic” or CCC’s) that affect any part of the equine gastrointestinal tract. When a non-vet notices a horse in colic pain, they have no way to differentiate these conditions. The problem might be minor or it might be fatal. Some of the common, simple conditions (gas or spasm) often disappear with a little time and no treatment. These are the same simple conditions that will disappear if a horse is walked, given a trailer ride, or given “a little Banamine® or Buscopan®”. A high percentage of horses showing signs of colic pain (with the simple CCC’s) resolve spontaneously. But if the pain is due to a true mechanical obstruction of the intestine (such as a displaced, twisted, or severely impacted intestine) the condition will worsen rapidly and can quickly result in death. These cases will require immediate veterinary intervention and possible intensive care or surgery. So when you see a horse in colic pain, you are faced with a situation that could go either way. For this reason, to reduce risk, it is best to contact your veterinarian at the first sign of any colic. Horses showing signs of colic can be classified into the following groups: Intestinal Dysfunction: 60-70% of horses showing colic signs have a “simple” colic (intestinal spasm, small accumulation of gas in the intestinal tract, mild impaction) and will resolve quickly with little or no medical treatment. A small number of these cases will require more intensive medical treatment. Inflammation or Ulceration: Inflammation, irritation or damage to the inner lining of the various parts of the intestinal tract can cause colic signs. Examples include gastric and colonic ulcers, parasite damage, and intestinal infections. Intestinal Accidents: This group of cases often requires emergency abdominal surgery, intensive care, or other aggressive veterinary treatment. Examples of these conditions include mechanical displacement or twist of the intestine, or entrapment of the intestine in a space it does not belong. More severe conditions can kill horses in a few hours. Fortunately, intestinal accidents only make up about 10% of colic episodes, but it is critical that these cases are identified early.  Prompt diagnosis and correct treatment will make the difference between life and death. Your Role To be a knowledgeable equine caretaker, you need to know something about colic: You should be able to identify the signs of colic. You should understand that the equine gastrointestinal tract is complex and sensitive. You should understand that there is a multitude of CCC’s. You should understand the basic facts regarding colic surgery (including cost) and whether or not you would consider colic surgery for each of your individual horses if faced with that decision. Beyond this basic knowledge, the most important thing to do when you identify colic is to call your veterinarian immediately, to alert them and to discuss the situation. Even though simple conditions may resolve spontaneously, it is best to start a dialog immediately. Depending on the circumstances, your vet may want to see your horse immediately or may want you to observe for a period of time to see if the problem resolves on its own. There are a few things that you should almost always do when your horse is showing signs of colic: Usually, you should remove all feed until intestinal function improves. How long feed needs to be withdrawn relates to the diagnosis and whether or not the horse has been given Banamine®. Unless your vet advises otherwise, always provide access to fresh water. Some hand walking may improve intestinal function and give your horse (and you) something else to think about. Excessive exercise is unnecessary and may stress the horse. If a painful horse will lie quietly, it is usually best to let them rest. If a horse is trying to roll, it may be best to hand-walk them, but always keep your safety as the priority. Keep the distressed horse away from fences and barriers and away from onlookers. Always keep the horse under close observation until the signs of colic resolve or as instructed by your veterinarian. Use Banamine® (flunixin meglumine) only as directed by your vet. Keep in mind that it is NOT a “cure for colic” but is a pain-relieving drug and can mask signs of colic pain. It can lead you to believe that the condition has resolved when in fact it has not. The message I send to my clients is: “I don’t need to see every horse that shows signs of colic, but I need to know about each one.” If you communicate with me, I can help you determine the ones that I do need to see. That will depend on the value of the horse (or your emotional attachment to the horse), your finances, and your tolerance for risk. Your Veterinarian’s Role Your vet’s role is to use physical examination and diagnostic tests to try to make a definitive diagnosis, or at least assign the case to one of the groups above as early as possible. An accurate diagnosis means appropriate treatment and accurate prognosis. The veterinary examination of a horse showing colic starts with a careful history. Certain types of colic are more common in certain breeds, ages, and in one sex or the other. Veterinarians consider these factors as they consider the possibilities for the CCC. A careful history can provide other clues that can help a veterinarian make a diagnosis. An important characteristic of a colic episode is the duration of pain, and responsiveness to pain relieving drugs. Certain conditions (large colon volvulus or twist for example) are known to be extremely painful. Vital signs such as temperature, heart rate, gum color, and intestinal motility (movement) are evaluated and make up an important part of the picture. Passage of a stomach tube gives valuable information about the function of the upper intestine and stomach, and may also be used to provide treatment with oral fluids and medications. A horse with blockage of the upper parts of the intestine may have accumulated fluid backed up under pressure in the stomach (horses cannot vomit) and this fluid may “reflux” from a tube placed into the stomach. Rectal palpation is a valuable tool for diagnosis of horses with abdominal pain. In this procedure, a veterinarian feels the abdominal organs and specific regions of the intestine through the rectal wall. Examples of rectal exam findings include accumulations of feed, fluid or gas in specific segments, or incorrect location of a specific segment. Abdominocentesis (belly tap) is sampling and analysis of the fluid that bathes the intestine. This procedure can give valuable information about the health of the affected intestine. Abdominal ultrasound is an extremely useful tool for adding information to the examination.  The size, shape, contents and movement of specific segments can be visualized. Blood work and other diagnostics are used as needed to give additional information. An experienced veterinarian quickly combines all the information gathered from the history, physical exam and diagnostic tests, and comes up with a likely diagnosis and a treatment plan. Treatment will depend on the specific condition suspected or diagnosed and might include medications for pain, oral and/or intravenous fluids, antibiotics, drugs to stimulate intestinal movement, ulcer medications, or laxatives, or enemas for foals. Sometimes the examination and diagnostics suggest that emergency colic surgery is the best or only course of treatment. It is expensive and requires an extensive rehabilitation period. The prognosis depends on the specific condition diagnosed, and often this remains unknown until the abdomen is explored by the surgeon. In general, survival rates are much better than they were in the past. Many horse owners cannot afford these services in today’s economy and horse industry. Your vet’s role is to try to diagnose what might be causing the colic pain in your horse, and then to provide you the diagnostic and treatment options and their costs. If your vet does not have the diagnostic experience or equipment to make a diagnosis, then they should offer you referral to someone who can. Once the problem has been resolved, it is their role to discuss management to reduce the likelihood of the problem in the future. Management for Prevention of Colic  CCC’s cause more equine deaths each year than any other cause. The economic loss to the industry caused by CCC’s is second only to lameness.  Why are CCC’s such a problem for domestic horses? Domestic horses evolved from wild horses. Wild horses were constantly active, moving and grazing on coarse grasses throughout the day, eating small and frequent meals. Their intestine evolved to accommodate this lifestyle. Unlike wild horses, many modern horses are confined in small areas and fed one or two rich meals per day. This lifestyle change works against the structure and function of the equine intestine. Good management practices mimic the “wild horse state” as closely as practical. While conditions causing colic can affect even the most well managed horses, smart management is a key component of prevention. It helps to consider colic “trigger factors” that are factors that may increase the likelihood of a CCC. Trigger factors include: Rapid Change in Feed or Management Stress, including Transport, Foaling or Weaning Major Weather Changes Stall Confinement Parasitism Sand Accumulation I encourage all horse owners to do the following to minimize intestinal problems in their horses: Make management and feeding changes gradually. Establish a consistent feeding and management routine, and stick to it. Provide frequent turnout or consistent exercise. Provide access to fresh water at all times. Feed multiple times during the day versus one big feeding. Consider the use of “Slow Feeders” that regulate the rate that a horse consumes hay. Feed a good quality and consistent hay as the staple. Keep the amount of grain fed to a minimum for the work the horse is doing. Avoid sand accumulation by not feeding on sandy soils. Use a psyllium supplement if necessary. Implement a veterinarian-approved parasite control program using fecal egg counts. Pay particular attention to mares around foaling time and to those horses that have had colic signs before. Handle those horses very carefully, as they may be more sensitive to triggers. Conclusion The key to preventing conditions causing colic is an understanding of what colic is and how the changed lifestyle we have imposed on horses contributes to the problem. The solution is good management that mimics the “wild state” and minimizes colic triggers. The key to saving horses affected by CCC’s is the early recognition of colic signs and the early involvement of your veterinarian. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated May 2014  
Equine Dentistry: Part 1 - The Basics In the last two decades there has been a revolution in equine dentistry.  Twenty years ago, very little effort was made to care for horse’s teeth.  Basic dental “floating” has been performed for hundreds of years, but techniques and knowledge did not progress much during that time.  Until fairly recently, many veterinarians had either little interest in doing dentistry or, if they did, they had poor equipment that did not allow them to do the work properly. Today equine dentistry is getting lots of attention.  There is a huge amount of information - and misinformation - available to horse owners.  It is important for horse owners to have basic knowledge about equine dentistry so that they can sort through this maze of material and make good decisions for their horses. Recent changes in equine dentistry include: Improvement in the quality of equine dental equipment.  There is now a huge variety of motorized instrumentation available for grinding equine teeth, as well as elaborate mouth speculums and hand instruments.  Motorized dental equipment is not necessarily superior to good hand instruments.  It simply makes the same job quicker, easier and sometimes more practical to perform. With the recent growth in knowledge and technology, dental techniques have been developed that allow more thorough examination and treatment of the horse’s mouth.  Proper use of high quality and well-designed instruments allows thorough grinding of dental overgrowths on all the teeth.  Techniques have even been developed that allow fillings and root canals to be performed on horses. In recent years, equine veterinarians have developed much more experience in dentistry and many of us take a special interest in this area of practice. In my experience, many horse owners are confused between dentistry performed for the health of their horse and dentistry performed to enhance performance at an intended discipline.  Professionals, in many cases, have not done an adequate job in explaining this difference.  The focus of this article will be on dental maintenance as it relates to the overall health of the horse. EQUINE TEETH In order to understand common dental problems and concepts of equine dentistry, it is important to know a little about the structure and function of equine teeth: Adult horses have between 38 and 44 teeth depending on gender, and whether or not an individual has wolf teeth. There are 6 upper and 6 lower front teeth.  These are called the incisors and are mostly used for grasping and nipping feed. Canine teeth are present (mostly) in male horses and developed as fighting teeth.  They have no chewing function but can become very sharp and occasionally can cause problems. Wolf teeth are tiny peg teeth just in front of the rows of cheek teeth.  They do not have a known function and are often removed because they are thought to cause discomfort from the bit in some horses.  Other horses do not develop wolf teeth. The important and unique teeth from a health standpoint are the cheek teeth - molars and premolars.  Equine cheek teeth have developed over millions of years as an efficient means for grinding coarse grasses.  Many horse owners have never even seen their horse’s cheek teeth, as they are far back in the mouth. The special structure of equine cheek teeth is very different from that of human teeth.  Horse’s teeth do not “grow.”  The permanent teeth in a young horse are very large, about 3 to 4 inches long, but are buried in the skull, and erupt through the gums throughout life.  The equine cheek tooth has a corrugated grinding surface that wears off against the opposing tooth and on feed.  This loss of tooth is accounted for over time by the tooth’s continual eruption through the gum. Modern, high grain diets favor the formation of dental overgrowths, as the teeth are not worn as effectively by these less abrasive feeds.  In a very old horse, the entire tooth has erupted and worn off, and the tooth ultimately just falls out.  Understanding this process of eruption helps explain how horses can develop dental problems, and gives some insight into the nature of those problems and how they are treated. Here are a few examples: If a tooth does not meet another, it will continue to erupt but not be worn, resulting in a long tooth which can cause pain or interfere with the grinding movement of the jaw.  These teeth need periodic shortening to prevent problems. In normal horses, the upper rows of cheek teeth are further apart than the lower rows.  As these teeth wear, dental points form on the outer edges of the upper teeth and the inner edges of the lower cheek teeth.  These points are normal, but they can become excessively large or sharp, and can cause pain when eating or interfere with normal grinding movement.  The treatment required is removal and smoothing of points and overgrowths. Equine “baby teeth” (deciduous teeth) erupt from prior to birth through the first months of life.  The permanent teeth replace these between 1 and 4 years, with specific times for specific teeth.  Dental problems can occur in young horses as these teeth are replaced.  Problems like retained caps (baby teeth) can cause pain or interfere with normal grinding movement.  Retained caps causing problems require removal. Any of the above will result in signs of dental problems. These signs include difficulty chewing, dropping feed, slow eating, and weight loss.  Incompletely ground feed is not digested and absorbed efficiently, resulting in weight loss or colic. THE EQUINE DENTAL EXAMINATION There is more to equine dentistry than just “floating” a horse’s teeth.  The idea behind dental health maintenance should be to preserve maximal, comfortable grinding of feed for as many years as possible.  How frequently a horse needs to have dental care for optimum health depends on age, management, genetics and many other factors.  The key is that all horses should have careful dental examination on a regular basis. Proper equine dentistry starts with a thorough history, physical exam and an understanding of that particular horses and client’s needs.  A thorough dental exam is a critical part of quality equine dentistry.  It requires good instruments,  good light and lots of experience to do well.  Regular dental exams and maintenance will prevent larger problems later and can be thought of as an investment in the future of a horse.  Ultimately, the most important part of sensible equine dental care is getting good advice from a veterinarian who understands equine dental health as it relates to the health of the whole horse. In Part II of this article, I discuss some of the facts, confusion and controversy that surround equine dentistry that is done for performance enhancement. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Equine Dentistry: Part 2 - Performance There are many different opinions on how effective dental treatments are on equine performance.  There is still much research to be done.  However, recent observation and research may be cause for reconsidering commonplace techniques in equine dentistry. As discussed in Part I of this article, an educated horse owner should have a basic understanding of the anatomy and function of equine teeth and understand the concept of continuous dental eruption.  Age and genetics also play a critical role in determining how much dentistry is required for each horse.  Since so much depends on the natural occlusion (the meeting of the upper and lower rows of teeth) and the chewing characteristics for each individual horse, understanding these things allows one to be aware of the different problems that can develop, and to be on the lookout for signs. Horses of different ages have different types of dental problems that can affect general health and performance. Young horses in training suffer from retained "caps" (baby teeth), sharp wolf teeth and sharp dental points.  Horses in their prime may have dental points and various dental overgrowths, depending on their specific occlusion.  More rarely, horses of any age can have a "dental accident" such as a cracked tooth or dental abscess.  Abnormal wear patterns like "wave mouth" may develop in horses who either have abnormal occlusion or who lack dental maintenance.  Aged horses, especially those that have not had consistent dental care, suffer from lost and severely worn teeth. Across the age groups and disciplines, the main emphasis behind dentistry to enhance performance include: Removal of any dental overgrowth that causes discomfort.  This is also beneficial from a health standpoint. Give special attention to smoothing cheek teeth that are in proximity to the bit.  This includes the so called "bit-seats."  The placement of a bit seat involves aggressive rounding and smoothing of the front premolar teeth.  This is somewhat controversial as it removes normal grinding surface from the tooth. The attainment of "maximal mobility" of the upper jaw with respect to the lower jaw by preventing locking of one jaw versus the other on dental overgrowths.  In theory, this allows less binding of one jaw versus the other when horses bend at the poll, and that this improves comfort.  The fine points of this approach are controversial. Aggressive maintenance and manipulation of the incisors (the front teeth) to ensure proper occlusion of the cheek teeth and to achieve maximum mobility of the jaws with respect to one another. There is debate in the horse, veterinary, and non-veterinary dental communities concerning the effectiveness of some of these treatments.  Some riders claim great benefit from them while others can’t detect a difference. Non-veterinary equine dentists have become common in the horse world.  Some of these individuals have developed great technical skill. They have, in many cases, led the way in terms of techniques and the development of equipment.  State laws regarding non-veterinary dental practice vary from state to state.  Most require that a veterinarian directly supervise the work of non-veterinary dentists.  It is illegal in many states for non-veterinarians to practice dentistry on client horses without direct supervision by a veterinarian.  This means that a veterinarian must examine the horse, decide what work needs to be done, and the non-veterinary dentist must work in the presence of the veterinarian.  It is also illegal for non-veterinarians to use sedatives and tranquilizers on client horses. Many equine veterinarians take a special interest in dentistry and have taken additional training in this area.  The advantage of using an experienced equine veterinarian is that he or she is able to evaluate the whole animal, rather than just the teeth.  Your veterinarian can then help you to formulate an approach that takes into account your goals and maximizes the health and well-being of your horse. The revolution in equine dentistry has benefited horse owners and horses in many ways. While most horses require some dental maintenance, not all require frequent and intensive motorized dentistry. The pendulum of thought on dentistry, like it has in many other areas of equine practice, tends to swing from one extreme to the other. I have always felt that too much dentistry is just as bad or worse than too little.  Obviously, equine teeth have worked for them for millions of years.  It never made sense to me that we should be too aggressive in trying to change something that we didn’t design in the first place, so I have always taken a thorough but conservative approach.  For people to think that because we now have the tools and techniques to aggressively change the shape of equine teeth, that we should, seems silly to me.  Yet many "equine dentists" have done just this, many without any real proof that what they are doing is necessarily beneficial to the horse or rider. Veterinarians thoughts on dentistry have changed as we have seen how horses that have received aggressive dental maintenance with motorized equipment have fared over the years. There have been many horses greatly helped by the smart use of these techniques. Unfortunately, some horses have been hurt by overaggressive use of power tools.  There is more and more controversy over how aggressive to be in shaping teeth. Recent research on normal horses has shown that in horses having no dental problems, there is no advantage (with respect to weight gain) to taking off dental points versus leaving them alone to function as nature intended. Any advantage is purely preventative. So where does this leave horse people with respect to a realistic and constructive approach to equine dentistry? Learn the basics of equine dentistry, including the unique problems for horses in different age groups. Distinguish between dentistry for optimal health versus dentistry done to maximize performance.  While certain performance-enhancing dental procedures may be useful in specific situations, understand that some of these claims may be exaggerated. Appreciate the fact that horse’s teeth have evolved for over millions of years. Whatever changes we make to their teeth, we should always take a humble approach. The best you can do for your horse is to become educated in all aspects of equine care, including dentistry.  In addition, regular examination by an experienced veterinarian will ensure that your horse’s general health, as well as their teeth, are maintained. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Equine Gastric Ulcers: What Horse Owners Should Know In the past 10-15 years, it has become clear how common gastric (stomach) ulcers are in trained horses and in the general horse population. This problem has a huge impact on the horse industry.  The development and more widespread use of the 3-meter endoscope over this time has given veterinarians a tool to visualize the inside of the horse’s stomach and definitively diagnose this problem.  Excellent recent research helps explain the different ways gastric ulcers are caused, and sheds some light on what we can do to prevent the problem. Gastric ulcers are very common in the performance horse population.  Endoscopic studies of horses in training have shown that up to 90% of horses stabled at race barns have stomach ulcers.  At least 60% of horses in other competitive disciplines have ulcers.  The prevalence of ulcers in horses that are not in training is lower, but still far higher than one might expect.  Gastric ulcers are also common in young horses, especially those that have other illness. CLINICAL SIGNS OF ULCER DISEASE The classic signs of ulcer disease in the adult horse are poor appetite, decreased performance, attitude and personality changes, poor body condition, rough hair coat, and low-grade or repeated colic episodes.  In foals, the classic signs of gastric ulcers are colic, diarrhea, teeth grinding, salivation and poor body condition. Temperament and pain tolerance can affect whether or not an individual horse shows obvious clinical signs. Some horses with mild lesions show obvious and “classic” clinical signs while others with more serious lesions may show very little sign of a problem. In some cases, horses with gastric ulcers exhibit well-established behavior patterns that are simply considered normal for that horse. Treatment of ulcers in these cases sometimes reveals a previously unknown - and sometimes very pleasant - underlying personality. DIAGNOSIS OF GASTRIC ULCERS The definitive way to diagnose gastric ulcers is with the use of a 3-meter video endoscope.  These scopes have been used at veterinary schools for years, but are now more common in private equine veterinary practices. The procedure goes something like this: The horse is kept off feed for 12 hours prior to the exam.  The horse is lightly sedated for the procedure.  The scope, a long, narrow tube that has a video camera at its tip, is passed through the nostril and into the stomach.  The stomach lining is visualized on a television screen.  Ulcers appear as erosions of varying size and depth in the surface lining. Ulcers are usually found in several typical locations within the stomach.  The severity of these lesions is visually recorded, and this recording serves as a baseline for studies performed during and after treatment. We have had a 3-meter endoscope in our practice since 2001 and have found it to be a great diagnostic tool.  It has allowed us to make a definite diagnosis of this common problem and to monitor the effectiveness of treatment. It has also allowed us to diagnose other problems of the stomach and esophagus, such as certain types of cancer. Other, “simpler” methods for determining the existence of gastric ulcers have arisen in the past decade as well. A fecal blood and protein test has proven to be unreliable in adult horses. Urinary sucrose testing may have some predictive value for bleeding into the gastrointestinal tract but requires urine collection and laboratory testing.  The standard diagnostic tool remains the 3-meter endoscope. It is often proposed that rather than going to the $300-$400.00 expense to diagnose ulcers definitively with an endoscope, one should instead simply put horses on medication and see if they respond. One real problem with this idea is that proven ulcer medications are more costly than the testing procedure. Use of unproven medications only further confuses the situation. Also, endoscopy provides a direct view of the stomach that is the only way to diagnose other possible problems. Things like stomach cancer, outflow obstruction and congenital abnormalities cannot be diagnosed any other way. WHY IS THIS PROBLEM SO COMMON? Understanding how equine gastric ulcers occur gives some insight into how to manage horses to prevent this problem.  Horses, unlike humans, secrete stomach acid continuously and independent of a meal.  The presence of food in the stomach buffers this acid and so helps protect the lining from damage.  Horses, unlike humans, have an upper portion of the stomach that has an unprotected lining and is vulnerable to damage by acid.  The lower portion is the acid-producing part and is more resistant to acid damage. Recent research has shown that when horses are exercised at a trot or gallop, the pressure in the abdomen (the space around the internal organs) increases. This raises the level of the “acid pool,” which normally lies down low in the more resistant portion of the stomach, to the more sensitive upper part.  This favors the formation of ulcers in this area. There are several different and distinct ulcer “syndromes” in different classes of horses that affect either the upper or lower portion of the stomach, or both.  The bacterial cause of ulcers that has been determined to be such an important causative factor in human gastric ulcers has not been found to date in horses.  Nutrition plays an important role in determining the level of acid in the stomach fluid.  High grain diets cause more acidity than low grain diets.  Alfalfa actually causes a lower acidity than grass hay.  One of the most important points is that ulcer syndromes can be unapparent, and the signs are often attributed to other causes. TREATMENT OPTIONS Horses diagnosed with gastric ulcers can be treated and often make full recoveries.  The most effective treatment for gastric ulcers in horses is the prescription drug omeprazole, trade names are Gastrogard® and Ulcergard®.  Gastrogard® is intended for the treatment of ulcers and Ulcergard® is intended for the prevention of ulcers and is given at a lower (preventative) dose. These are specially formulated pastes developed from a drug used to treat human ulcers.  They act by directly inhibiting acid production by the acid-producing cells in the stomach.  They are highly effective but also very expensive. Other medications that have historically been used to treat gastric ulcers have been shown not to be as effective, and require multiple doses per day.  These medications act by a more indirect route.  They include ranitidine (Zantac), cimetidine (Tagamet), and the ulcer coating agent sucralfate (Carafate).  Antacid medications are marketed with great claims for success, but have been shown to only lower acidity in the horse's stomach for short periods of time. That said, they are probably better than doing nothing and the products have become quite popular. PREVENTION Awareness is the key to prevention.  The more you know about gastric ulcers, the better you will be able to manage your horses to avoid them.  I regularly suggest the following preventative measures: Remember that if you do make feeding changes, make them over several days. Feed only as much high-carbohydrate grain as is necessary for the intensity of training. Keep high bulk feed (hay or grazing) present for your horses as much as possible.  The less time a horse spends standing around with an empty stomach, the better. Consider the timing of feeding versus training.  Do not train your horse on an empty stomach. Recognize and consider that alfalfa actually lowers stomach acid, and feed it accordingly. Be on the lookout for subtle signs and be ready to change your management accordingly. Some research suggests that corn oil may be protective of the stomach lining. If you are concerned that your horse may have gastric ulcers, discuss it your equine veterinarian. They can help make a definitive diagnosis and help you make the right management decisions. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Equine Infectious Diseases & Prevention Maximizing your own knowledge of horse health enables you to make intelligent decisions that save you money while providing the best care for your horses. Understanding the fundamentals of equine infectious disease and vaccination is an important part of that. In the world of infectious diseases, things are constantly changing. Diseases wax, wane, and evolve over time in response to poorly understood and complex biologic pressures. The battle to control these agents is also ever changing as we learn more about the diseases and develop new vaccines and control methods. Vaccine types and availability change frequently as well. This article summarizes my current perspective on equine infectious disease prevention.  See also Deciding When to Use "Risk-Based" Vaccines. FUNDAMENTALS Bacterial and viral organisms commonly cause infectious (contagious) disease in horses. These organisms, called “infectious agents” are transmitted in many different ways (specific to the agent) from direct contact between horses to transmission by insects. Whether or not a horse becomes infected in a given situation depends on a balance of several factors including: The animal’s susceptibility to the disease: A combination of genetics, health, general immunity and immunity to the specific disease in question (altered by vaccination). Good general health is critical to a functioning immune system and disease prevention. The characteristics of the infectious agent: This includes how potent and contagious the infectious agent is, how high a dose of the agent contacts the horse, and the mode by which this dose is presented (ingested, inspired, etc..). Prevention of infectious disease thus involves much more than just vaccination. Smart management means keeping horses in excellent general health, maintaining specific immunity through appropriate vaccination, and reducing exposure to infectious disease agents by understanding how they spread. The American Association of Equine Practitioners (AAEP) regularly publishes updates and guidelines for horse owners and veterinarians regarding recommended vaccines. You can find these recommendations and a variety of other helpful information at Generally, I agree with the AAEP’s recommendations, but I always seek to customize them based on a client’s unique needs. Specific protocols also should be followed with pregnant mares and foals. They have special vaccination requirements. CURRENT STATUS OF SOME EQUINE DISEASES & VACCINE RECOMMENDATIONS West Nile Virus has been a severe problem for the horse industry since the first cases in the U.S. on the East Coast in 1999. It spread rapidly westward over the next few years, killing large numbers of birds, horses and some people. The peak incidence in New Mexico occurred in 2003. There were hundreds of cases in New Mexico that year and our practice treated a very large number of cases. Since then, West Nile infection has become less common in our area, but it is now considered endemic (established permanently) throughout the United States. This disease is transmitted by a mosquito that has fed on an infected bird, and is not transmitted directly from horse to horse. Recommendation: West Nile is a core vaccine strongly recommended by the AAEP. All horses in the U.S. should be vaccinated for West Nile Virus once annually. This is generally done in the spring, before mosquito season. There are now several vaccines available which rely on different technology in their formulation. All are considered effective if used annually. At least one of the newer vaccines may provide faster immunity than the others, and with fewer initial doses. Your veterinarian will have an opinion on which product is best for your situation. Symptoms of Eastern and Western Encephalomyelitis (a/k/a sleeping sickness) are similar to those caused by West Nile Virus and the virus itself is similar. These important mosquito-transmitted diseases have been overshadowed by West Nile Virus over the past 10 years, causing some horsemen to de-emphasize vaccinating for them. Like West Nile, these diseases fluctuate on a cycle dependent on immunity in bird populations, and many other factors. In the summer of 2010, there was an epidemic of Eastern Equine Encephalitis in New York and Ohio that killed many horses. The severity and extent of the outbreak may partly have been caused by the poor economy. Financially stressed horse owners cut expenses by reducing vaccination, resulting in more susceptible horses. Recommendation: Encephalitis is a core vaccine strongly recommended by the AAEP. The vaccine is effective and inexpensive. It is usually combined with West Nile Virus and Tetanus. Recommendation is annual vaccination, timed before mosquito season in the spring. Tetanus is a paralytic disease caused by a toxin produced by the bacteria Clostridium tetani. This organism is common in the environment, present on many surfaces, and becomes a potentially fatal problem primarily when it is introduced into wounds. Recommendation: Tetanus is a core vaccine strongly recommended by the AAEP. This vaccine is highly effective, safe, and inexpensive, and should be given to every horse each year. It is often combined with encephalitis and West Nile vaccines and so is often given at the same time, in the spring. While immunity to tetanus probably persists longer than one year after vaccination, our recommendation still is to vaccinate annually. Until there is more convincing scientific evidence that equine immunity lasts longer than a year, it makes more sense to be safe than sorry. “Strangles” (a/k/a Distemper) is a respiratory disease caused by an abscess forming bacteria, Streptococcus equi. The classic sign of strangles is abscess formation around the throat and under the jaw. The name “Strangles” comes from these often large swellings, which in their most severe form can cause difficulty in swallowing and breathing. Abscess formation is often combined with nasal discharge, fever and cough. The abscesses typically break open and drain yellow pus. The disease is common and is highly contagious to at-risk horses. It is easily transmitted by contact with secretions and drainage containing the organism. It is also carried on the hands of handlers and on shared tack and equipment and through shared water. Vaccination has proven difficult for this disease. There is a modified-live intranasal strangles vaccine available and considered relatively effective. The intramuscular vaccines have not been very effective. The problem with all of the vaccines has been a relatively high adverse reaction rate and limited effectiveness. The modified live intranasal vaccine causes a form of strangles in a very small percentage of vaccinated horses. It is also dangerous because it can be inoculated into and cause abscesses in the tissues at other vaccination sites. Recommendation: We currently recommend the use of the intranasal vaccine 1-2 times per year, only for horses in which the risk of strangles infection outweighs the risk of side effects from the vaccine. We feel that the vaccine does help reduce likelihood of infection and severity of disease in a population of horses. A critical part of reducing strangles incidence is management of horses to reduce strangles exposure (quarantine before introduction of new horses into a herd) and immediate quarantine of any affected horses. Your veterinarian is the right person to help you decide the need for this vaccine and to administer it for you if needed. Influenza. There has been lots of talk in the past few years about human and bird influenza. Influenza virus is common in horses also, causing high fever, cough and nasal discharge. It is highly contagious, spreading rapidly through a group of horses. It is expelled by coughing horses and can infect horses up to 30 feet away. As with all flu viruses, the equine influenza virus is constantly changing, making it difficult to make a vaccine which contains the most current version of the virus. Recommendation: We currently recommend vaccinating for this disease using one of several recently developed vaccines which contain the more appropriate strains. Some vaccines are given intra-nasally while others use the intramuscular route. Horses in contact with others (show and performance horses, horses boarded at barns) are at risk for the disease and should be vaccinated more frequently. Vaccination is less crucial for isolated horses. Vaccines with more current strains have been shown to produce better immunity to more currently relevant versions of the virus. Typically, influenza vaccines are given at least twice annually to at-risk horses. Equine Herpes Virus (a/k/a rhino or rhinopneumonitis) are several related viruses that can cause respiratory, neurologic signs, or abortion in horses. In the past several years, there have been significant outbreaks of EHM, (Equine Herpes Myeloencephalopathy), the neurologic form of disease in the U.S. Many horses have died or been euthanized in these outbreaks.  One unique characteristic of equine Herpesviruses is that they can lay dormant in infected horses and then can causes signs of disease when immunity decreases because of stress or other factors. Recommendation: We recommend frequent (at least twice a year) vaccination using specific, newer generation vaccines, based on the specific situation and risk. Pregnant mares should be vaccinated as directed with a vaccine licensed to protect against the abortive form of this disease. Vaccination probably does not prevent the neurologic form of disease. The benefit of giving rhino vaccine may be less for older and more isolated horses. Your veterinarian can help you decide whether or not the vaccine is needed for your situation. Rabies is a rare but fatal disease in horses that is transmitted by the bite of an infected animal (bats and skunks in our area). The AAEP recently made rabies a core vaccine for horses. In the past year, there have been cases of equine rabies in Colorado and a higher incidence of rabies in wildlife in New Mexico. Recommendation: For our region, we recommend vaccinating horses for rabies annually. The vaccine is relatively safe, effective and inexpensive but should be administered by a veterinarian. Equine Viral Arteritis (EVA) is a viral respiratory disease that is transmitted either through venereal means (through breeding) or through transmission from coughing horses. It is carried by infected stallions, which can infect mares through their semen. An outbreak in 2006 prompted New Mexico to require testing and vaccination of commercial breeding stallions. In our state, commercial breeding stallions must be blood tested initially, and then vaccinated annually with a modified live vaccine (ARVAC). Recommendation: Commercial breeders should familiarize themselves with this disease and their state regulations related to it. This may include annual vaccination of breeding stallions. OTHER DISEASES There are common diseases for which we do not have a working vaccine. An example of this is Dryland Distemper (a/k/a “Pigeon Breast” or “Pigeon Fever”). This disease is common in the Southwest, and most commonly presents as large abscesses on the chest, belly or sheath. Since there is no commercial vaccine, control measures for this disease are limited to management. Management centers on minimizing contamination of the environment by infected horses and good fly control. There are other, less common infectious diseases that affect horses in the United States for which there may be vaccines available, but the cost/ benefit of their use may be questionable. An example of this is Potomac Horse Fever, a rare disease in our area. This disease can cause life-threatening diarrhea in horses. It is a difficult disease to diagnose the disease definitively. The vaccine is of questionable effectiveness. For these reasons we do not recommend routine vaccination for this disease in our area. However, in the Northeast where the disease is more common, the cost/benefit is different and the vaccine is used more. VACCINES - IMPORTANT POINTS TO CONSIDER Vaccines are not all created equal and are constantly being improved. Your equine veterinarian should be current on new vaccine development and can help you select the best vaccine for your needs. Vaccines have historically been created by preparation of all or part of the infectious agent, either killed, or inactivated and alive, mixed with a delivery liquid called an adjuvant. The agent (or part of an agent) in a vaccine agent stimulates the immune system to produce antibodies against the disease. Antibodies are infection fighting proteins which bind to a specific agent and help destroy it. Some new vaccines take advantage of great advances in our understanding of the immune system and genetic engineering. These products may contain only a small, key part of the organism or its genetic code but still promote excellent immunity. They tend to be more effective and safer than older vaccines. New delivery approaches target key organ systems more directly and so may produce better immunity; Examples include the newer intranasal vaccines. ALTERNATIVE APPROACHES & THE CHOICE NOT TO VACCINATE There is currently debate in the horse community (and beyond) over how much vaccination is necessary. There is some suggestion that holistic means are sufficient to prevent infectious disease and that vaccination is not necessary. Current research and experience supports core vaccination as critical to good horse health care. Ask your veterinarian before you rely exclusively on alternative approaches. While we cannot rule out that some holistic or natural agents may be helpful, there is very little known at this time about their true effects. The best policy for now is not to take a chance. We are lucky to have highly effective and safe vaccines which have been proven to safely reduce your horse’s chances of succumbing to serious disease. Let your veterinarian help meld your own philosophies on equine health care with their latest research. DO IT YOURSELF? Anyone can give a vaccine if they have learned the proper technique involved. While many vaccines are now available over-the-counter, there are several key reasons to continue to involve your equine veterinarian in vaccinating and examining your horses. Your veterinarian stays educated on new vaccine development and so can provide the most effective, current and safest vaccines. He or she administers these vaccines correctly and on a proper schedule, and maintains complete vaccination records. As of the time of this writing, many vaccine manufacturers will stand behind their vaccines. If after vaccination a horse becomes infected by a disease that the vaccine was intended to prevent, some manufacturers will pay for part or all of the veterinary treatment required. However, in order to receive such compensation, many of these companies require that their product be administered by a licensed veterinarian., Your veterinarian may actually save you money. They will discourage you from over-vaccinating your horses or using inappropriate or unneeded vaccines. Most importantly, I believe vaccination of horses should be combined with veterinary consultation and examination of the horse. For me, this is an opportunity to talk to my client and examine the horse, and to get to know horses in health rather than in crisis. I enjoy discussing goals and management of my clients’ horses as it relates to their health care, and I feel that the time spent is of real value to horses and their owners. Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCUpdated March 2013  
Equine Laminitis: Part 1: What is it? Laminitis (a/k/a "founder") is a disease of the feet common in equines - horses, donkeys, and mules.  This disease is one of the most heartbreaking and costly to the equine industry.  It can cause severe and debilitating lameness and may necessitate euthanasia.  It can seemingly come out of nowhere, or can follow as a sequel to other serious diseases that have been successfully treated and resolved. The mechanisms of laminitis have been studied intensively for many years but there is still much that is not understood.  Recent findings have contributed more to our understanding of this disease process.  The purpose of this first article is to define laminitis and discus current ideas on how it happens.  The second part discusses some mainstream approaches and new ideas with respect to treatment and prevention. SIGNS OF LAMINITIS Laminitis typically results in very severe lameness that is usually worse in the forelimbs than hind limbs.  Anyone who has witnessed a horse with laminitis is unlikely to forget it.  In an effort to avoid bearing weight on the very painful front feet, horses show a characteristic stance with the hind limbs pulled far under the body and the front feet far out in front.  They may even lie down to get off the feet entirely.  Less painful laminitis often results in a horse that looks like he or she is “walking on eggshells.” EQUINE FOOT STRUCTURE & LAMINITIS While other grazing animals may get laminitis, none show the dramatic signs that equines do. In order to understand the mechanism of laminitis, it is important to understand the basics of equine foot structure. Equines are the only family of mammals that have evolved to walk on the tip of one finger (digit). The equine foot is a miracle of engineering.  The entire weight of the horse is borne by the coffin bone, which is suspended above the sole of the foot by its attachments to the outer hoof wall.  This unique attaching layer is called the "laminar layer." The key to understanding laminitis is to understand that a mechanism exists in the foot that allows the coffin bone to be securely suspended by the hoof wall, but also allows the hoof wall to slide over the bone as it grows. The coffin bone (pedal bone, or P3) is attached to the outer hoof wall by the laminar layer.  You can see the laminar layer on the sole of a newly trimmed foot as the “white line,” just inside the outer hoof wall.  Microscopically, the white line is made up of two layers of laminae, one that is attached to the outer hoof wall and one attached to tissues firmly glued to the underlying coffin bone.  The attachment between these two laminar layers contains an active process involving thousands of interconnected and branching microscopic fingers of live tissue between the coffin bone and outer hoof wall.  The millions of live cells making up these fingers of attachment are under precise control by signals from the body and local signals from the foot tissues. I like to use Velcro as a model to illustrate the laminar layers. Imagine the coffin bone glued to the soft Velcro layer. Now imagine the outer hoof wall glued to the rough Velcro layer. The Velcro surfaces come together at the white line. Now imagine that there is precise control of this attachment which allows limited sliding of the hoof wall over the coffin bone.  Tiny releases and reattachments constantly occur to allow the hoof wall to grow down from the coronet band (the hairline of the hoof). Protruding into and between these laminar layers is a fine web of tiny blood vessels that bring oxygen and other essential nutrients to the cells.  At any one time, the cells making up these fingers are mainly adhered to one another. Precise control of the laminar cells allows movement of the hoof wall along the coffin bone while never completely releasing it and thus never allowing it to alter its position within the foot. THE MECHANISM OF LAMINITIS - "LAMINITIS TRIGGERS" The word laminitis means inflammation of the laminae.  It is a disease that involves dysfunction of this unique system of attachment discussed above.  It can progress to allow complete breakdown of the structure of the foot. The old mechanism for laminitis that I learned as a veterinary student involves blockage of the circulation to the laminae, leading to cell injury and stretching of the laminar attachments. New research has shown that certain biochemical “laminitis triggers" can cause over-activation of this release mechanism, allowing the coffin bone freedom to move within the hoof.  Horses undergoing this “over-release” show the signs of laminitis. To what degree the coffin bone moves is dependent on many factors but, in general, the more movement of the coffin bone, the more severe the damage, and the less likely the horse is to make a complete recovery.  Understanding the new concept of laminitis triggers is important.  Any substance that can function as a trigger can cause the mechanism of laminitis.  The blockage of blood supply to the laminae is likely a later contributor, but the main event in initiating laminitis is this over-release of the laminae caused by the laminitis trigger. Where do these laminitis triggers come from?  Classically, founder has been thought of as a disease resulting from grain overload.  Unlike cattle, which ferment feed in a rumen (or foregut), horses are known as hindgut fermenters. This is because the large specialized hindgut, or large colon is the place where the tough structural components of grass are broken down by the action of bacteria.  Ordinarily, simple sugars and starch are absorbed upstream of this by the small intestine before many reach the colon.  An overload of this system with sugar or starch from a sudden load of grain or other high starch feed allows increased starch or simple sugar to reach the colon.  This can result in a die-off of the normal bacteria here and a shift to new types and numbers of bacteria.  Some of these new bacterial types may produce substances that act as triggers, and result in the signs of laminitis. However, there are many other laminitis triggers.  Bacterial toxins coming from retained placenta, abdominal infection, or from intestine damaged by a colic episode, also can be triggers.  There are specific toxins found in nature that are known to be direct triggers, such as Black Walnut wood shavings. PREDISPOSING CAUSES Anything that makes the laminar cells more susceptible to a trigger will increase the chances of a horse developing laminitis.  Genetics plays a role in the sensitivity of a given horse to laminitis triggers.  Some breeds are more sensitive than others. Endocrine disorders, hormonal problems such as Equine Cushing's disease (also known as PPID) or Equine Metabolic Syndrome (EMS), can predispose horses to laminitis by increasing sensitivity to triggers.  A horse that has had prior laminitis episodes is more sensitive to recurrence as well. For a variety of reasons, horses that are abnormally fat are more predisposed to developing laminitis than a horse in normal body condition.  Obesity may cause specific problems with the circulation in the foot, interfering with delivery of oxygen and nutrients to the live cells of the laminae.  Because of this, these laminar cells may be more sensitive to the action of a trigger. Reaction to any trigger causes the same end result: Either over-activation of the releasing mechanism, or damage to the live cells themselves.  Either alone or together, these two factors allow movement of the coffin bone within the hoof.  Once the coffin bone rotates or moves within the hoof, the live layers of the sole may be crushed and the blood supply to the laminae damaged.  This further contributes to a cycle of destructive events in the hoof, which ultimately can break down the entire structure. In Part 2 of this article, I discuss ways to prevent and treat laminitis in its acute and chronic forms.  I pay special attention to some new research regarding feeding and grazing management to avoid this serious disease. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Equine Laminitis: Part 2: Treatment & Prevention In Part 1 of this article, I explained what laminitis is and described some current ideas on how it is caused.  I discussed the anatomy of the attachments of the hoof wall to the underlying pedal bone as it relates to the development of laminitis, and described how “laminitis triggers” (substances in the blood coming from a variety of causes) free these attachments and allow movement of the coffin bone away from the hoof wall.  I gave examples of direct predisposing factors and indirect predisposing factors. In this article I discuss what you and your equine veterinarian can do to prevent and treat laminitis.  Specifically, I discuss how horse owners can help prevent this disease with basic changes in management based on exciting new research on feeds and grazing. PREVENTION The most important thing you can do to prevent laminitis in your horses is to establish a good relationship with an experienced equine veterinarian.  They can provide appropriate advice and consultation and help you to recognize breed and individual risk factors when buying horses.  Your veterinarian can conduct a pre-purchase exam that can help prevent you from purchasing a horse that has experienced laminitis in the past. Horse owners should also be able to recognize the signs of laminitis that we discussed in the last article.  If you notice these signs, you should call your vet immediately.  The longer a horse shows signs of laminitis, the more permanent the damage. Laminitis may be progressing before you actually see the signs.  Time is a critical factor.  If you know that your horse is at risk for whatever reason, don’t wait until you see the signs of laminitis to call your veterinarian. Other important points: Maintain your horses at a healthy weight and avoid a high grain diet.  Prevent your horses from becoming obese on pasture. Understand the predisposing factors and be alert for the classic signs of these problems.  These diseases include Equine Metabolic Syndrome (EMS), Equine Cushing’s disease (PPID), and others. Prevent accidents like grain overload by paying attention to your methods of grain storage. If your horse breaks into the feed room and you suspect grain overload, call your veterinarian immediately. Maintain your horse’s feet regularly with the help of a skilled farrier. Recognize and do what you can to avoid acute diseases that can cause laminitis.  Examples include retained placenta in mares, colitis, pneumonia, and certain types of colic.  If they do occur, contact your veterinarian for prompt and appropriate treatment of the primary problem, which will reduce the possibility for laminitis to occur. VETERINARY ASSESSMENT & TREATMENT Assessment of the feet for severity of coffin bone rotation is done using radiography (x-ray).  Treatment depends on the severity of the rotation.  Prompt and effective veterinary treatment of the predisposing cause of the laminitis is critical to successful treatment of the laminitis itself.  Treatment of laminitis involves attempts to break the cycle that takes place in the foot by the use of anti-inflammatories and pain relievers.  Historically we have used drugs that opened the vessels in the feet.  New research has shown that applying and maintaining ice to the feet can prevent laminitis in horses at risk for it.  However, these same studies show little effect in treatment of laminitis once the process has already started. There are many different approaches veterinarians use to mechanically treat acute laminitic cases.  The main goals are to provide pain relief, stabilize the coffin bone in the foot (minimize its rotation), and maintain the circulation of the foot.  How effectively these last two goals are achieved using different approaches is not well agreed upon at this time.  Some ideas that are currently in favor include increasing the angle of the foot with a wedged heel, and providing support to the cup of the sole to help prevent rotation.  In many practices, high-density Styrofoam blocks are taped to the soles of the feet to give the horse comfort and to help break the cycle of pain and inflammation in the feet. In our practice, we generally do not favor shoeing horses in the early stages of laminitis.  Shoeing is a critical part of later treatment.  Once a horse has been affected by laminitis and has gone through the early stages, corrective shoeing and trimming by an experienced farrier is a critical part of management.  The relationship between horse owner, veterinarian and farrier is a vital one in the management of these horses. NEW THOUGHTS ON PREVENTING LAMINITIS - NSC'S Important new information for horse owners is the discovery that non-structural carbohydrate "NSC" (also known as fructan or soluble sugar) are strongly linked to the development of laminitis.  The highest risk is for horses grazing stressed, slow growing grass in the spring and fall.  These stressed plants have the highest levels of NSC and so are the most dangerous to horses. This research is very important to us here in the high desert, where conditions are inconsistent and plants are placed under so many different stresses from day to day.  This new information fits with the high incidence of laminitis that we see in grazing horses in early spring and late fall in our area.  Both plant type and environmental stress on the plant are very important to their NSC level.  It is not necessary to understand the details underlying this research, but it is very important for horse owners to understand the general concepts in preventing laminitis. Here are some of the main points: Cold weather grasses like fescue and brome have higher NSC's than native pastures and warm weather grasses like gramma grass.  Surprisingly, alfalfa is often lower in NSC's than many grasses. Testing growing grasses and hays for NSC's is possible through some forage laboratories and is the best way to know the laminitis risk associated with a given forage. Horse owners should restrict or avoid grazing during times of highest plant stress.  The most dangerous periods are spring and fall, especially during periods of warm days and freezing nights.  Another dangerous time is right after moisture breaks a drought.  In very cold weather, the green stubble found at the base of a completely dormant plant may be very high in NSC's and very dangerous to a susceptible horse.  Avoid grass under these conditions. Overgrazing a pasture to limit intake of green grass is not a good option, as the highest level of NSC's is in the stem base.  NSC's are lower in plants at night and early morning, so limiting turnout time to these times makes sense. Bran is very high in NSC's, so is not a good supplement for horses at risk for laminitis. Soaking hay is a way to drastically reduce NSC's in hays fed to at-risk horses and horses suffering from ongoing laminitis. Grazing muzzles and dry lot grazing in horses predisposed to laminitis is a way to provide exercise while preventing excessive intake of forage. If you have any questions about assessment or treatment, call your equine veterinarian. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Equine Navicular Disease/Chronic Heel Pain: A Common But Misunderstood Problem The loss of use resulting from chronic lameness (pain in a limb that causes visible change in gait) costs the equine industry hundreds of millions of dollars annually.  Foot lameness makes up a high percentage of this lameness, and the heel structures of the foot are the most commonly affected part of the foot.  Within the heel sits the infamous navicular bone.  Problems associated with the navicular bone and surrounding structures are the most common cause of chronic front limb lameness in horses. Navicular disease (also called navicular syndrome or chronic heel pain), refers to a poorly understood degenerative process within the navicular bone.  In this article, I discuss the basic anatomy and function of the navicular bone and the heel area. I then describe the types of horses often affected by the disease, diagnosis of the problem and ideas for treatment and management.  Much is still not understood about this problem.  In fact, new diagnostic technology has shown us that lameness problems in the heel of the foot are more complicated than we previously thought. FORM & FUNCTION A little basic anatomy is critical to an understanding of this problem.  The coffin bone is the main foot bone and sits within the hoof and is approximately the shape of the hoof.  Running down the back of the limb, diving into the heel of the foot and attaching to the “palm” of this coffin bone, is a rope-like tendon called the deep digital flexor tendon.  Think of a horse bearing weight and imagine the fetlock (ankle) sagging down under the weight.  The flexor tendon acts as a sling to support this weight.  With weight-bearing, the flexor tendon is stretched (under tension), by the horse’s weight.  The navicular bone (named after its ship-like shape) sits wedged (as a pulley) under this tendon and behind the coffin bone and redirects the force of the tendon such that the mechanics work to keep the toe pulled down and the lower limb functioning. Given this structure, it is important to understand that the navicular bone is a critical part of the coffin joint of the lower limb.  Likewise, because of the mechanics involved, the navicular bone is under tremendous compression with weight bearing. SIGNS OF NAVICULAR DISEASE Usually navicular disease appears as a low-grade lameness that gradually worsens, often misleading horse owners into thinking that “this is just the way my horse travels.”  In many cases, the chief complaint is simply poor performance or unwillingness to work.  People often notice that the problem is worse on hard ground, seems to be present in both feet, and seems worse in a circle to one direction or another.  Some horses “point” the more painful foot when at rest to relieve pressure and pain in the heel.  Some develop a short, choppy gait. As with many types of lameness, the abnormality is most noticeable at the trot.  Swelling or heat in the area is generally not present.  Unlike many other problems that result in lameness, navicular disease does not usually improve with rest. OTHER IMPORTANT POINTS Navicular disease is very common in Quarter Horses, but is also common in other breeds, including Thoroughbreds and Warmbloods.  Generally, it occurs more in large, heavy horses with relatively small feet. While certain foot characteristics seem to be associated with the development of navicular disease, it can affect feet of any shape or conformation. While heel pain can be associated with poor shoeing or trimming, this is often not the case. Genetics, conformation, hoof imbalance, work intensity, and many other factors are thought to play a greater role in the development of this problem. Unlike many arthritis-type lameness problems, “classic” heel pain is most commonly seen in relatively young horses. Classic navicular disease process can be seen at autopsy as aging-like bone degeneration. THE VETERINARY EXAM Diagnosis of this disease is based on a thorough veterinary exam that takes into account the type, breed, conformation and age of horse, and the history of the problem.  A thorough physical exam and lameness exam generally suggest that the origin of the problem is not higher up the limb and seems to affect both front limbs. Foot conformation and gait characteristics are evaluated and support the diagnosis.  Flexion exams and hoof tester responses add to the whole picture, from which a diagnosis is made. A critical part of the exam is the diagnostic nerve block.  In this procedure, the nerves that supply sensation to a particular part of the limb are anesthetized with a short-acting local anesthetic.  The horse’s gait is evaluated after the area in question is numb - in this case, the nerves supplying feeling to the heel and navicular.  Following the block, the heel would be numb and the horse would be trotted again.  If the pain comes from within this “blocked” area, the lameness is improved.  If pain is coming from somewhere higher up the limb, the horse would still be lame and different blocks would need to be done to determine the origin of the pain.  It is important to understand that the nerve block does not only block the navicular bone in this case, but the surrounding structures as well.  This complicates the diagnosis. If the exam and nerve blocks define the heel as the painful area, high quality radiographs (x-rays) are taken and provide additional information.  The veterinary diagnosis of this area takes into account the history, clinical exam, nerve blocks and x-ray, and combines it with personal experience and the “art of practice” to reach a diagnosis. TREATMENT & MANAGEMENT The good news is that many cases navicular disease can be helped with treatment.  Proper hoof care and shoeing remains the foundation of treatment.  When shoeing a horse diagnosed with navicular disease, the goal is to balance the foot and to move the base of support of the foot backward.  This approach to shoeing is thought to mechanically relieve stress on the heel and navicular area and thus relieve pain.  This is often accomplished with a bar shoe of some type.  The important thing for a horse owner to know is that there is not just one way to shoe these horses.  There are a variety of techniques that accomplish similar objectives.  Working with your veterinarian and an experienced farrier will ensure proper shoeing. In addition, I commonly inject medication into the coffin joint or navicular bursa in attempt to break the cycle of pain and inflammation in the foot.  I have found that this approach, coupled with the change in mechanics from proper shoeing, often results in improvement. I have also found that systemic medications are helpful in some horses.  Phenylbutazone (bute) helps, but it is often not a good answer for long-term maintenance.  Drugs like isoxsuprine seem to help some horses, but it is not understood how.  Neurectomy or nerving is, in my opinion, helpful to some horses as a last alternative.  This procedure involves removal of a segment of each of the heel nerves, which provides long-term relief of pain.  Obviously it does not correct the problem.  This procedure has its complications, but in some cases it is the only alternative for a horse to live without severe chronic pain.  I have found that other surgical procedures yield mixed results. CONCLUSION Problems in the navicular area have been recognized for centuries.  However, they are poorly understood and have been treated as though there is one simple process occurring.   Radiographs have long been considered the most important part of reaching a diagnosis.  However, they do not always directly correlate to the diagnosis or severity of the problem.  New imaging methods like MRI allow us to see both bone and soft tissue structures of the foot in never-before-seen detail.  What we have learned is that there are a variety of problems that can cause pain in this area that are indistinguishable without utilizing these new techniques. Examples of injuries that look like navicular disease are strains of navicular supporting ligaments or tiny tears in the deep flexor tendon down low in the foot.  It is important to distinguish these from navicular disease, because the treatment for these types of injuries differ. Rest allows ligament injuries to heal, but is not be expected to help a horse with “Classic” navicular disease.  More use of these advanced diagnostic techniques in private practice will no doubt help us to diagnose and treat these horses more effectively now and in the future. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
Equine Skin Conditions: Part 1 For large animals, horses tend to be very sensitive and also tend to have unique veterinary problems.  Their skin is no different.  Horses have a relatively “thin” skin and can have a wide variety of skin problems.  Skin disorders are common and tend to be highly visible to owners.  While many don’t think of the skin as an organ, it is actually the largest organ in the body.  It is designed to house and protect the rest of the organs and body systems. It forms a semi-permeable yet tough barrier to the outside world, protecting horses from every conceivable environmental insult such as trauma, parasites, insects, ultraviolet light and temperature extremes. The skin is complex, containing multiple layers of cells. These layers contain sweat glands, blood vessels, nerve endings, touch receptors, pores, hair and many other structures.  Astute horse owners should pay attention to their horse’s skin and coat as they would any other aspect of their horse’s appearance or conformation.  Identifying problems early allows horse owners to catch problems before they have progressed and potentially become more difficult to treat. Beyond this, the skin and coat are a window into the horse’s general health.  Nutrition and general health are reflected in the coat and skin condition.  A poor coat or skin disorders can be a sign of underlying diseases.  Equine skin disorders can be classified in several different ways. Understanding this is the first step toward a better understanding of skin disorders, how they are diagnosed, and ultimately how they are treated and prevented. BREED/AGE/COLOR/BODY LOCATION Specific skin problems affect specific breeds, ages, and colors of horses.  Different breeds are predisposed to specific skin problems, either indirectly through breed characteristics like color, or directly through genetics. Examples of breed predisposition that affects equine skin include: A Genetic abnormality like HERDA (Hereditary Equine Regional Dermal Asthenia), affects specific foundation lines of Quarter horses.  This is a skin disorder that has become common in Western performance horses.  HERDA comes from a genetic defect in a skin protein that makes the skin abnormally stretchy and easily torn.  This disorder is usually detected in young horses when they are handled and started in training. Thoroughbred horses tend to be thin-skinned and more sensitive to insect irritation and inflammation. Pony breeds tend to have a higher incidence of Equine Cushing’s Disease (PPID) and the classic long, poorly shedding coats associated with that condition. Certain disorders affect horses of specific color.  Horses with non-pigmented (pink) skin are predisposed to skin cancer, like squamous cell carcinoma, especially at high altitudes. Thus, breeds like appaloosas and paint horses with white hair and pink skin have a higher incidence of this problem.  A high percentage of true gray horses (with black skin) develop melanoma tumors.  These hard black nodules are commonly found around the anus, behind the jaw bones, under the ear, the lips, and sheath.  These lesions are generally benign, meaning that they are quiet slow growing bumps that have a low likelihood of spreading throughout the body. However, a small percentage of horses with melanoma have a malignant form that spreads throughout the body, and may cause serious disease or death.  A horse owner should know about the risks of melanoma in gray horses and understand the unique nature of this problem. Some disorders affect horses of a specific age. An example is facial warts in young horses, which are common but usually go away on their own in a few months.  Cancerous lesions tend to affect older horses. Some disorders are seen in specific locations on the horse’s body.  Pastern dermatitis, also known as “greasy heel" or "scratches” is dermatitis (inflammation) that affects only the heel and pastern areas of the lower limb.  This is usually caused by bacteria or fungus.  Dermatophilosis, also known as "rain scald" or "rain rot" is a bacterial infection of the skin and appears as crusts with hair loss that usually occurs along the back and top-line.  “Aural plaques” is a scaly wart-like condition thought to be caused by a virus, which is commonly found on the inside skin of the external ear. THE VETERINARY DIAGNOSIS I always stress the importance of diagnosing a problem before treating it.  With equine skin conditions, however, I have found that owners are even less likely to seek out a veterinary diagnosis early on.  Since skin problems are obvious to owners and results of their treatment more readily apparent, many owners treat these conditions themselves.  But the results are mixed.  When incorrectly treated, the problem may still resolve, persist, or worsen.  It can be a bit of a gamble.  Proper diagnosis involves looking at the whole horse and not just the skin lesion.  It involves understanding what factors are involved in making a diagnosis, and it should involve a call to your veterinarian for guidance. Experienced veterinarians can usually recognize the appearance and patterns of most of the skin diseases in horses and can reliably diagnose and treat them.  The veterinary examination starts with a careful history. Important questions include:  How long has the problem existed?  Are other horses affected?  What are your feeding and what is your parasite control program?  Has the horse had any other health problems? The physical examination of a horse with a skin problem starts from the big picture and then focuses down onto the specific skin lesion. What is the breed, color, age and sex of the horse?   How is the horse’s general health?  What is the appearance, number and location of the lesions on the horse’s body?  An important part of the veterinary diagnosis of skin disease is a specific and accurate description of the lesions: Are the lumps under the skin or within it? Are the lesions crusts or scales? Is there hair loss and is it associated with inflammation or not?  Are these areas itchy or do they appear to hurt? How large are they?  Once a careful history is taken and a thorough examination is done, a veterinarian may be ready to make a diagnosis. If the signs are not typical of any specific disease process, a veterinarian may choose to treat the horse for what he or she thinks is most likely the problem, and may run some other diagnostic tests while initial treatment is taking effect.  These tests include culture for infectious organisms like bacteria and fungus, examination under the microscope for external parasites like mites or lice, blood work to evaluate the general health of the horse, and taking a skin biopsy. SKIN BIOPSY Generally, veterinary diagnosis of equine skin problems usually does not involve a biopsy or other laboratory testing.  Most diagnosis is made through a history and exam of the horse and the skin lesions.   Only the more confusing or difficult problems require additional diagnostic tests. A skin biopsy consists of a veterinarian surgically removing a small piece of skin within the affected area that is a full skin thickness deep.  The biopsy is preserved in formaldehyde and sent to a laboratory, where a trained dermatohistopathologist - a veterinarian trained in the microscopic diagnosis of veterinary skin problems - prepares, stains and examines the specimen under a microscope.  Based on this examination, the basic nature of a skin lesion may be generally diagnosed as traumatic (caused by injury), infectious (caused by bacteria, virus), immune mediated, neoplastic (cancerous), or other. In addition, the pathologist may find fungus or bacteria as well or may even find an even more specific reason for the problem.  The veterinarian then ties in this laboratory information with the horse’s overall health picture and clinical signs, and comes up with a diagnosis and treatment plan.  Skin biopsy is an excellent tool to assist in the more difficult diagnosis. Part II of this article focuses on some common equine skin disorders, their diagnosis, treatment and prevention. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Equine Skin Conditions: Part 2 This article discusses skin-related problems that primarily affect horses during the summertime.  Equine skin problems arise more frequently during the summer months for several reasons.  First, horses tend to be more active.  They are ridden more and are reproductively active and so they tend to incur more injuries and skin wounds and are exposed to infectious diseases.  Second, intense summer solar radiation causes sunburn and photosensitization.  Third, flies and other insects contribute to a whole host of different skin-associated problems and other diseases.  Understanding how these factors contribute to equine skin diseases gives us clues as to how to prepare for and avoid these troublesome problems. THE ACTIVE SUMMER LIFESTYLE The fact that horses are more active in the summer means that there are more opportunities for accidents that result in skin wounds.  More travel means more stress and contact with other horses, increasing exposure to contagious skin disease like Equine Ringworm.  This disease results typically in circular areas of hair loss and peeling.  It is not caused by a worm but by a fungus called a Dermatophyte.  Horses are ridden more and as a result we see more problems like “girth itch” also caused by Dermatophyte, and saddle sores.  Girth itch is a fungal infection of the skin under the saddle and is common in working horses and is often spread by infected tack.  Saddle sores are a common problem in summer and are usually seen in horses ridden with ill fitting tack or poor riding technique. INTENSE SUMMER SUN In the Southwest, sunburn is a common problem in non-pigmented skin.  At our practice, we see this mostly in the summer because of more intense UV light.  Horses with white faces often sunburn, especially on the muzzle.  Paint horses with short coats are often affected, especially those with non-pigmented skin on the top line.  High SPF sunscreens, applied and reapplied as needed, can help protect areas that burn.  Fly masks and sheets may offer additional protection. Different from simple sunburn is photosensitization, meaning hypersensitivity to sunlight.  Photosensitization appears as severely damaged areas of pink (non-pigmented) skin.  The disease process tends to be much more severe than simple sunburn, with the affected areas often severely scabbed and crusted.  This problem occurs because of the presence of photoactive plant pigments in the skin which, when contacted by UV light, change to a form that damages the skin.  These pigments reach the skin in several ways, either through ingestion or contact.  This type of photosensitization is known as primary photosensitization and is caused by only specific plant types.  In our area, we commonly see it associated with certain species of clover and even alfalfa, mostly on pasture, but sometimes in hay. Secondary photosensitization relates to liver dysfunction.  A healthy liver is critical to the breakdown of plant pigments found in all plants.  When the liver does not function properly, these pigments reach high levels in the blood and skin.  The pigments then react to UV light and damage the skin.  As with primary photosensitization, this does not occur in the same way in pigmented skin because UV light is absorbed and weakened by the dark pigments in the skin.  A specific type of photosensitization affects the non-pigmented lower limbs (white socks and stockings) of horses and causes severe crusting and swelling of the limb.  Horse owners should understand how plant ingestion and contact can cause damage to white-haired areas. PESKY INSECTS Flies are a familiar summertime problem.  All equines are irritated by flies but some are more sensitive than others, with significant breed and individual differences.  For example, Thoroughbred horses tend to be more sensitive to flies than some of the “thicker skinned” breeds.  Culicoides hypersensitivity is an allergic skin disease caused by hypersensitivity to the night biting midge Culicoides, small black flies that are also known as  "no-see-ums."  They are mostly active at night.  While all affected horses are irritated by these insects, some develop allergy to them. The classic appearance of allergic skin reactions in horses is peeling, crusting and hair loss around the tail head, and/or under the mane.  Less frequently, the underline is affected.  The horses tend to be very itchy, and so worsen the damage by constant scratching.  Horses affected by this problem, in our region at least, are mostly those stabled or pastured near water.  Prevention involves understanding that this is a problem caused in the evenings.  Thus the most effective prevention is fly control targeted to protect horses during this time. A common summer problem in our area is hypersensitivity to biting flies like horse and deer flies.  As with Culicoides, all horses are bothered and bitten, but only certain horses become allergic and thus become more severely affected.  Hypersensitive horses develop hives (wheals) around the neck and shoulders.  Fly hypersensitivity can also appear as lines of crusting on the chest. Treatment of both these hypersensitivities involves protection from the flies using insecticides and other management techniques. It is important to understand that the skin damage and reaction is not directly caused by the insect bite but by the body’s over-reaction to the bite.  Therefore, steroids and antihistamines are sometimes used for treatment of severe cases in order to dampen the immune response. A more recent and holistic treatment is hypo-sensitization therapy, where tiny amounts of the offending allergen is injected under the skin over months, and until the horse becomes tolerant of it. There are many ways to control stable flies, none of which are perfect.  The most important relate to manure and facility management to minimize the areas which are available for fly reproduction and development. By far the most important point is to remove manure and other waste promptly during fly season.   At our facility we combine aggressive manure management with the use of the feed-through insect growth regulating drug found in Solitude IGR, which has made a difference. PIGEON FEVER While not really a skin disease, “Pigeon fever” is an important enough disease that I will discuss it briefly.  Pigeon Fever (also known as Pigeon Breast or Dryland Distemper) is an infection caused by a bacterial organism that is transmitted by stable flies.  This is a very common and troublesome summertime disease in our area.  Flies are thought to introduce the bacterial infection into the skin and underlying tissues.  The bacteria are carried by the blood stream deeper into the tissues and local lymph nodes, where they cause abscess formation.  The abscesses are most common in the deep tissues of the chest.  They also commonly occur on the underbelly and sheath areas in geldings. Abscesses typically are very slow growing and sometimes only appear months later, during the fall and winter months.  The disease is called pigeon fever because horses with abscesses of the chest can have a huge protruding chest, like a pigeon.  There is no vaccine for the disease.  Treatment involves abscess drainage, nursing care and selective use of antibiotics.  Most horses eventually recover on their own, but some cases require veterinary care and can take months to resolve. MANAGEMENT & PREVENTION Anticipate the greater level of summer equine activity and how it contributes to skin-related diseases. Pay attention to basic issues like stable and trailer safety, proper nutrition, vaccination and parasite control, and tack fit and maintenance. Learn to recognize the signs of the commonly seen skin diseases and be on the lookout for them. Protect horses from intense UV light and be aware of the difference between sunburn and photosensitization. Minimize fly related skin disease by a balanced program of facilities management. Maintain contact with your veterinarian so that he or she can help guide you in prevention and treatment of summertime skin problems. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
Equine Wounds: What Horse Owners Should Know Wounds are one of the most common equine emergencies.  Horses are especially prone to wounding themselves because of their size and speed.  Their often violent flight response means that collisions with objects are common.  Their large size and fast movements mean that the forces of impact are great and wounds are often serious. This article explains basic wound healing and successful wound care.  It is very important to differentiate between potentially serious wounds, and ones that will heal well on their own or with simple care.  The key, as I've discussed in many other articles, is knowing when to call your veterinarian for advice.  He or she will help you to determine which wounds you can treat on your own and those that should be seen.  See Handling Equine Emergencies: What Horse Owners Should Do, Horse Owner Self-Help: Knowing When to Call a Veterinarian.  BASICS OF WOUND HEALING There are three basic “stages” of wound healing starting from the moment that the wound is created until all healing and scarring has taken place.  These stages overlap but their division into stages simplifies understanding.  Depending on the wound in question, the healing process can take months or longer. The initial stage, lasting from the moment of wounding to a few days following, involves the formation of a clot and the recruitment of infection fighting cells and more blood flow to the area.  This process allows the breakdown of irreversibly damaged tissue and foreign material, and controls wound infection. The next stage involves the creation of a scaffold in the wound defect (granulation tissue) that serves as a basis for more mature tissue to be laid down and for skin to migrate over. This stage lasts from about five days to several weeks after wounding.  The granulation tissue produced is the red colored filling tissue so familiar to horse owners which, when it grows above the wound bed, is known as proud flesh. The next stage involves wound contraction as the skin is actually pulled together by cells in and around the wound, and skin migration, as skin cells multiply along a front and migrate over the wound. The healing wound then gains strength over weeks to months as more organized, tough tissue replaces the early scar.  This stage actually starts as early as 2 days after wounding and so overlaps the other stages. How well wounds heal depends on many interrelating factors affecting each of these stages.  Wounds penetrating internal body spaces like joints, sinuses, and the ab domen often result in infection of these structures, which can be life threatening.  Wounds that contain foreign bodies like wood or other material will not heal until that material is removed. HEAD WOUNDS [caption id="attachment_7064" align="alignleft" width="300"] Severe equine head wound before and after repair.[/caption]     Head and neck wounds are common in equines.  There are several important things to know about head wounds: The head has an excellent blood supply that helps with rapid healing, but there is little extra skin over the bones of the face.  Thus, wounds with significant skin loss take a long time to heal.  If there is skin loss involved in a new wound, a veterinarian may be able to save lots of healing time by repairing it if the skin is still viable. Head wounds often result in loose flaps of skin.  A veterinarian should repair these wounds as soon as possible.  Suturing these wounds saves months of healing time and results in improved cosmetic appearance. Head wounds often involve bone, which is just under the skin in most places.  Thus, a common complication of head wounds is damaged and infected bone.  This may require surgical removal immediately or at a later date. The sinuses are air-filled cavities within the skull that communicate with the upper respiratory tract.  Wounds fracturing the facial bones and entering into these cavities can result in their infection, which can be a chronic and severe problem.  Signs of sinus infection are yellow or whitish nasal discharge (often with a foul odor), and chronic swelling or drainage at the wound site. A severe wound of the head or neck requires assessment of the whole horse to ensure that their brain and spinal cord have not been injured. Wounds near to or involving the eye require a veterinarian’s assessment immediately.  Proper repair of eyelid lacerations is critical to the future function of the eye. BODY WOUNDS Body wounds are common and most heal quickly.  As was discussed with head wounds, the critical question is whether the wound involves deeper structures or penetrates into the abdominal cavity. A wound that penetrates into the abdominal cavity or chest introduces life-threatening infection into the cavity and results in severe illness within hours. [caption id="attachment_7073" align="aligncenter" width="802"] Severe abdominal wound, before and after treatment. The wood splinters (shown on the far right) penetrated into the abdominal cavity, introducing life-threatening infection. Prompt and aggressive treatment was required to save the horse.[/caption] Wounds along the top-line lack the ability to drain, and so pose more problems healing. Wounds to the underside of the body are common and generally heal well as long as there is no foreign body and the wound does not penetrate body cavities. Whether or not body wounds are sutured depends on many factors, including location, age of wound, degree of contamination, and muscle damage. Uncomplicated body wounds (especially chest wounds) left open often heal very well by wound contraction. LOWER LIMB WOUNDS [caption id="attachment_7061" align="alignright" width="225"] Lower limb equine wounds can be serious, even life-threatening, if vital structures are involved.[/caption] Lower limb wounds are very common and are always potentially very serious.  For the best outcome, any wound below the hock or carpus (knee) should be evaluated by an experienced veterinarian. Vital structures like joints, tendon sheaths, ligaments and bone are just a few millimeters from the skin surface.  If these structures are involved, life threatening or chronic lameness may result.  Excellent veterinary management of these injuries from the beginning is the key to successful outcomes. Excessive movement, little loose tissue for contraction, and a poor blood supply in the lower limb results in difficult and slow wound healing. Overgrowth of healing tissue (proud flesh) is common in lower limb wounds of the horse.  Proud flesh is excessive healing tissue that accumulates to a level above the wound bed or surrounding skin surface.  It inhibits healing by preventing the skin from migrating over the wound bed.  It must be removed and managed.  Proper wound care controls the formation of proud flesh. Suturing of selected lower limb wounds is usually accompanied by careful bandaging or casting, and long-term confinement.  A properly applied cast can result in a quick, cosmetic and functional outcome in what otherwise would be a slow and difficult healing process. UPPER LIMB WOUNDS Upper limb wounds are common and generally heal rapidly. There is much more musculature in the horse’s upper limb than in the lower limb, so bone and vital structures are generally less often involved. There is a better blood supply here than in the lower limb, which aids wound healing.  The additional tissue mass means wound contraction can aid healing more than in the lower limb. Severe wounds to the upper limb can result in tremendous muscle loss but usually this does not reduce function much. Cared for properly, most of these wounds with extensive muscle loss heal well and result in acceptable function of the limb. Veterinarians sometimes choose to repair these wounds by suturing, but often recommend treatment leaving the wound open. WOUND GUIDELINES Know when to call your veterinarian, and when in doubt, give them a call anyway. Understand that wounds in proximity to or involving eyes, joints and tendon sheaths, abdomen (belly area), and other body cavities may be very serious and may require immediate veterinary attention. Depending on the location, age of wound, degree of contamination and other factors, your veterinarian will choose whether or not a wound should be sutured.  While horsemen know that there is an early window of opportunity to suture wounds, there are many other factors that determine whether suturing is the treatment of choice. Always call your veterinarian immediately if a wound causes lameness visible at the walk. Bleeding is rarely life threatening in horses, although it can be with laceration of the large vessels in the body and neck.  Because of their size and large blood volume, horses can lose gallons of blood before going into shock.  It is important to understand that even severe bleeding can usually be controlled with direct pressure.  This means firm and even pressure right on the bleeding vessel.  This is most commonly needed on the lower limb, where the large vessels are commonly cut. Antibiotics are often used in wounds that involve or are near important structures or are infected.  Antibiotics should only be given after consultation with your veterinarian. Phenylbutazone (bute) is a potent pain reliever and anti-inflammatory.  It and other anti-inflammatory medications can be helpful in some wounds to reduce swelling and pain, but should be used under the supervision of your veterinarian.  They can be dangerous when used incorrectly. Bandaging is very helpful in some lower leg wounds, but must be done correctly.  Improper bandaging can damage vital structures of the limb.  Improper bandaging may also lead to increased formation of proud flesh. Ointments should be used cautiously and under the direction of your veterinarian.  While some have positive effects, many actually retard healing.  Wound treatments that make miraculous healing claims are usually too good to be true. In our practice, I encourage my clients to sent to me photos of wounds via e-mail on my computer or phone.  By seeing these wounds, I can better advise my clients regarding whether a particular wound should be examined by me. In assessing the severity of equine wounds I examine their location and the structures involved.  The largest uncomplicated wound may heal uneventfully and with little scarring, whereas the smallest wound in the wrong place can be life-threatening.  While horse owners can treat many less severe wounds successfully, the key is early communication with your veterinarian to decide whether veterinary care is needed.  The Internet, email and Smartphones provides a new and great opportunity for quick, easy and effective communication of wound severity to your veterinarian. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   Would you like to learn more about equine wounds on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:  Observation - Drainage from Wound, Generally Observation - Proud Flesh, Healing Wound Developed Raised Red Tissue Observation - Puncture Wound, Anywhere on Body Diagnostic - Wound or Draining Tract Exam Skill - Treat Wound on Difficult Horse          
Handling Equine Emergencies: What Horse Owners Should Know I define an “equine emergency” as any problem with your horse where a delay of appropriate treatment might endanger their future quality of life or their soundness.  Horses have a unique ability to injure themselves, often seriously.  This is due to a combination of size, power and speed coupled with an overdeveloped fight or flight response.  They are also notoriously sensitive for their size.  Equine lower limbs and intestinal tracts are two anatomical areas that are especially predisposed to injury and illness. Horse owners should be well prepared for the common equine emergencies.  This preparedness is founded on basic veterinary knowledge, access to the right supplies and equipment, and a solid relationship with your equine veterinarian.  In this article, I briefly discuss what I consider to be the most significant and common types of equine emergencies.  I also explain the importance of the veterinary–client-patient-relationship (VCPR) as it pertains to emergencies; a subject that is rarely discussed and is very important. The VCPR The most important thing you can do as a caretaker for your horse is to have a good relationship with your equine veterinarian.  They are ultimately the best resource for you to turn to in an emergency.  The better able you are to communicate effectively with them, especially in stressful situations, the better care the horse gets and the better the outcome.  Mutual trust is critical in the VCPR. Here are some ways that you can contribute to that mutual trust: 1. Contact Information.  Know how to reach your veterinarian in an emergency.  Good locations to keep veterinary contact information are your horse trailer, cell phone, stall door or posted on the refrigerator.  These days it is easier than ever to stay in contact. 2. Early Contact.  Call at the first sign of a problem that could become an emergency - not when it has progressed to a crisis! Even if your veterinarian does not recommend an examination, at least they are put on notice and can advise you on a course of action. 3. Horse Owner Self-Help.  If you call your equine veterinarian at the outset of a problem, your horse may not need to be seen.  The safest and best thing for a horse is to be directly examined by a veterinarian, because we can only learn so much over the phone.  However, for clients who I know and trust, I often try to help manage simple problems without a visit.  Generally, I don’t charge my regular clients for telephone help.  With good information and communication, I can often help make a determination as to whether or not the horse needs to be seen on an emergency basis.  I am always careful to follow-up to ensure resolution of the problem. 4. Cost.  Equine veterinary practice is expensive to deliver, and 24 hour care is an especially hard service to provide in this day and age.  The costs for the luxury of 24 hour emergency care must be passed on to horse owners.  You should always anticipate being charged an emergency or after-hours fee.  I try to give clients an estimate before I come out, whether they ask for it or not.  If cost is a concern, ask your veterinarian to give you an estimate before they commit to the visit. 5. Your Skills.  Learn to competently take and record your horse's temperature, pulse and respiration.  Understand why these finding, as well as a complete history, are important to your equine veterinarian.  All of this information can be very helpful in trying to make a determination regarding whether or not he or she needs to see your horse immediately, in a day or two, or not at all. 6. Your Supplies.  A limited stock of supplies and equipment can be very helpful for a horse owner to have in an emergency.  This is especially true for clients who live a long distance from their veterinarian.  An inexpensive stethoscope and thermometer can be bought at a drug store.  Learn how to use these instruments.  They allow you to provide very useful additional information. Your equine veterinarian can help you assemble and maintain an inventory of supplies and equipment (an emergency kit). 7. Medications.  As with supplies, it may be helpful for horse owners to have a small number of medications handy in case of an emergency.  However, you must have a basic understanding of how to administer them, what they do, and their limitations.  There is strong legal regulation on veterinarians regarding dispensing prescription medications.  Your veterinarian’s willingness to dispense items will depend on the existence of a good VCPR.  Improper or careless use of drugs and veterinary equipment can be fatal to a horse and dangerous to handlers.  I only dispense medications to clients who I trust and who fully understand their benefits and limitations.  If I dispense a prescription medication for emergency use – such as Banamine® – I ask that my client call me before giving it to their horse.  For more information, see my other article Bute & Banamine®: What Horse Owner's Should Know. 8. Routine Preventative Care.  In order for me to advise a client over a phone regarding an emergency, it is extremely helpful if we already have an established VCPR.  I encourage my clients to let me get to know them and their horses in health by doing routine well-horse exams along with preventative care in both spring and fall.  This enables me to become familiar with the owner, horse and facility and better prepares me in the event of an emergency.  A strong VCPR often provides me with the ability to find problems before they evolve into emergencies. THE MOST COMMON EQUINE EMERGENCIES EQUINE COLIC (ABDOMINAL PAIN): Colic is one of the most common emergencies and is often the most distressing for horse owners.  You should be able to recognize colic signs.  Keep in mind that these can range from very subtle (like being slightly off feed or laying down a little more than usual), to obvious signs (like rolling, pawing, and kicking at the belly).  See Colic Surgery: What Horse Owners Should Know and my other articles on equine colic for more details. Horses with signs of colic can be dangerous to handle because they can suddenly collapse, roll, paw or kick.  Be especially careful when handling these horses.  Sometimes, the best thing you can do is leave them alone until your veterinarian advises otherwise. If you see signs of colic, call your veterinarian immediately and tell them that your horse is showing colic signs.  Do this before you give your horse any medications.   Be ready to describe the signs of colic and your physical findings (if you were able to safely take them), including temperature, gut sounds.  Heart or pulse rate are especially helpful pieces of information to provide to your equine veterinarian, if you can. 70% of colic cases are simple gas or spasm causing pain, and resolve spontaneously or with simple treatment.  Your veterinarian may ask you if you have access to a pain reliever and if so may ask you to give it and give the horse some time.   Always take feed away from a horse that has been treated with a pain reliever.  Many drugs can mask the signs of colic, delaying proper treatment. Horses that do not respond to medical therapy require a proper diagnosis.  Colic is just a sign of an underlying problem - usually abdominal pain, and that the task is to diagnose what is causing the pain.  Some diagnoses may require emergency colic surgery.  Colic surgery now averages about $7,500.00 nationally, depending on the diagnosis and procedures performed.  It is important for you to have a general sense of whether or not you would have your horse operated on if you had to make a choice.  The key to this is educating yourself about the pros and cons of colic surgery, and balancing that with your financial wherewithal. Your veterinarian can help you answer these questions.  WOUNDS: Wounds are also a very common equine veterinary emergency.  If you have any doubt about the severity of a wound sustained by your horse, call your veterinarian immediately.  Time is an important factor in the effective management of wounds. The most important factor in assessing the severity of a wound is not how large the wound is, but where it is located and whether it might involve a critical structure like tendon, bone or especially a joint or tendon sheath.  For years now, I have asked clients to e-mail digital photos of wounds to me.  This is an excellent way for me to determine those wounds that I need to see from those that the client can manage themselves.  In general, potentially serious wounds are those that: Are near or involve a joint, tendon or tendon sheath. This is true for most lower limb wounds. Involve the coronet or hoof. Involve the eye or eyelid. Punctures that may involve deep structures within the abdomen or chest. Less serious wounds are those that are to the heavily muscled upper limb, chest or body and do not involve deeper structures.  See my other article Equine Wounds: What Horse Owners Should Know. Blood-loss is rarely a life threatening problem for horses.  The vast majority of even large and apparently severe wounds stop bleeding before enough blood is lost to be life threatening. That said, it is important to be able to control bleeding if you must.  The critical skill to know is how to apply direct pressure to a wound.  This does not mean applying a tourniquet.  It means consistent, firm pressure focused right on a bleeding vessel.  You can do this with a finger and a thick wad of gauze or a pressure bandage with a wad of gauze focused only on the bleeding area. GENERALIZED TRAUMA OR SWELLING: Cases of swelling of a location are common reasons for horse owners to call their veterinarian.  Often, these are traumatic in origin but can be due to stings, snake bite, and local allergic reactions.  Again, providing your veterinarian with good photographs can be helpful, in addition to providing the results of your whole horse assessment. LAMENESS:  Severe or non-weight bearing lameness is always an emergency.  Mild lameness can often wait for a scheduled appointment.  Lameness should always be taken seriously and when in doubt, you should call your veterinarian.  Most lameness is in the foot, so pick it up and examine it, feel it for heat and compare the temperature of it to the other feet.  Examine further up the limb and compare this to the other limbs.  Stand in front and to the side and compare the lame limb to the others visually.  Run your hands up and down the limb, feeling for swelling, heat, pain, or wounds.  Take your horse’s temperature.  Learn to take digital pulse. Provide all of this information to your veterinarian when you call. When dealing with severe lameness, always rest a horse in a box stall until the veterinarian can examine him or her.   The most common cause of sudden severe lameness is sole abscess and sole bruise.  However, fractures, infected tendon joints or tendon sheaths and other problems can also cause non-weight bearing lameness. EYE INJURIES: Disease affecting the eye should be thought of as an emergency as well.  The eye is a vulnerable, sensitive, complex and vital organ.  Disease processes of the eye can progress quickly, resulting in irreversible damage and potentially permanent blindness.  The most common cause of emergencies involving the eye relates directly or indirectly to trauma.  Call your veterinarian immediately when your horse has an eye problem.  Use a quiet, darkened stall and/or a fly mask to protect it until your veterinarian arrives.  See my other article The Equine Eye: What Horse Owners Should Know. Other examples of common equine emergencies that may require veterinary attention include: CHOKE:  Esophageal obstruction, a/k/a choke is a common problem in older horses or horses fed pelleted feeds or beet pulp.  When a horse is choking you often see nasal discharge with feed, severe salivation, and gagging. GRAIN OVERLOAD:  This can result from a horse gaining access to grain storage and eating large quantities of grain. DOWN OR CAST HORSE:  A relatively common complaint is a horse, which is down and unable to rise. DIARRHEA: This problem in the adult horse is uncommon but is also considered an emergency. CONCLUSION I have discussed above what I consider to be the most common and significant types of equine emergencies, but the variations are limitless.  Ultimately, a horse owner must use common sense, knowledge and instinct to determine what constitutes an emergency. Remember that good communication with your veterinarian is a critical factor.  Guidance is just a phone call away and can mean the difference between the life and death of your horse. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Horse Breeding: Balancing Breed & Specific Goals with an Emphasis on Soundness Recent tragic events, like the breakdown of the race horses Eight Belles and Barbaro in highly publicized races, have raised many questions regarding the causes of these tragedies. Many factors, including training techniques, medication rules, and track surfaces have been and will continue to be analyzed and discussed.  But questions have also arisen regarding the genetics and breeding of these horses.  As an equine veterinarian who sees a large number of horses each year, I see some firsthand examples of what both thoughtful and thoughtless breeding has yielded. Over the years, the Thoroughbred breed has changed body type. The old style horse was taller and lankier, more of a distance runner. Today’s horses are more heavily muscled, broad-chested and smaller boned. These horses may not have the skeletal structure to support the huge forces generated at high speeds. There are questions about racing statistics and how they relate to durability and soundness. Breeding stallions today on average have had fewer starts than counterparts from the past. The number of their progeny that make it to the track is smaller. The average number of races run by race horses in the country has decreased. All of these indicators may show a trend toward a less sound, less durable animal intended more for a brief flash of stardom than for long term soundness. The bottom line is that breeding and genetics must be considered as part of the approach to reducing the number of this sort of tragedy. Quarter Horses have suffered the effects of our intense selection for arbitrary characteristics at the cost of functional conformation and longevity.  The well-known QH stallion “Impressive” sired numerous massively muscled halter horses that repeatedly won in the show ring. Unfortunately, he also passed on a gene that coded for a defective muscle cell. This gene became very prevalent in halter horses, and resulted in the disease called Hyperkalemic Periodic Paralysis (HYPP) a/k/a “Impressive Syndrome” that was a fatal or debilitating disease for many horses. More recently, HERDA (Hereditary Equine Dermal Asthenia or Hyperelastosis cutis) became prevalent in western performance quarter horses strongly line-bred from Poco Bueno stock.  HERDA results from defective connective tissue underlying the skin. The effect of this disease is very elastic skin, which pulls and tears away from the underlying tissue.  In this case, it was a matter of line breeding closely related horses until the prevalence of this recessive gene became great enough that the disease became an undeniable problem.  Today, genetic testing allows breeders to detect carriers of both of these genes so to avoid using these horses in their breeding programs. It is commonly said that “the foot and bone has been bred out of the Quarter Horse.” In certain lines, this is undoubtedly true and is evident in other breeds as well.  A large percentage of American Quarter Horses today no longer have a job. They live standing in a stall or turnout and are fed twice a day. Some of them are shown, and a relatively small number are used as performance animals. Due in part to this change in use, many horses are now bred for arbitrary characteristics that have no bearing on soundness, conformation or durability. Many are large bodied, heavily muscled horses with small feet. Cutting horse lines tend to be small horses with very light bone and joints that are not well suited to the pounding that they must endure.  Some Arabian lines have been bred for elegantly refined heads and necks, while the rest of their skeletal structure has been deemphasized or simply ignored. For each breed, there is opportunity for reflection on the good and bad that has been gained through selective breeding. Obviously, there are foals being born today that are great representatives of each breed. However, breeders should always remember to balance intense selection for winning performance with characteristics of durability, soundness and conformation. What is the future of horse breeding? How can we be more effective in our selection such that we move these breeds in a direction that is sound for the long term?  We should heed lessons learned from nature.  Wild horses tend to be modest-sized, and have heavy foot structure and bone for their size. That is always a fallback position for a functional horse. If you take on the responsibility to breed horses, take the responsibility seriously and think twice about what characteristics you are seeking to emphasize and deemphasize, by balancing the quest for novel or flashy traits with a solid basis in conformation and performance. Along with breed specific traits, all horse breeds should have good minds, feet, bones and general conformation. A beautiful coat or massive muscling doesn’t mean anything if not supported by a strong foundation of foot, bone tendon and joint. Understand the principles of conformation and recognize and understand the basics of lameness. Do not breed horses that have not shown fitness in every way, whether from a lameness standpoint, general health, behavioral or breeding standpoint. Where available, use genetic tests to ensure that detectable diseases are not passed down. Focus on the actual performance and longevity of potential sire and dam rather than the relationship to a well-known horse. Similarly, select sires based on their performance record, not the fact that they have a familiar name on their pedigree or are a pretty color. Most of what is discussed above relates to horse buyers as well.  You drive the market for certain characteristics and you can help ensure that horses are bred to last by demanding soundness and good conformation. A purchase exam performed by a qualified veterinarian is an important part starting point. Through sound breeding choices we can all help try to produce a more sound and durable horse, and hopefully reduce the incidence of these tragedies. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated 3/12Originally published in The Horseman's Voice, 2010  
Horse Management During Drought Conditions Several regions throughout our County are currently experiencing drought conditions. These dry spells pose some unique healthcare and management challenges for horses.   Whether it is stress from heat and blowing dust, changing feeds or dwindling water supplies, the additive stresses from drought can cause potentially serious health problems for horses. Understanding and anticipating these problems will help maintain your horse’s health and welfare during this stressful time. Horses that are stressed for any reason, including drought, benefit from good basic care. It is important to ensure that all horses are properly vaccinated and dewormed.  In addition, stressed horses require the other basics, like good shelter, nutrition, hoof care, and fresh water. Horses that are normally maintained on dry-land pasture are affected most by drought, as their feed supply dwindles and their management requires change.  Any grass that is still present on pastures is usually severely drought-stressed.  Under environmental stress, grass undergoes periods of rapid growth followed by periods of dormancy, and this extreme growth pattern poses increased risk for laminitis and colic.  Horses that have been eating a dry hay diet do better if they are given time for their intestine to adjust to green grass again.  When we do get moisture again, be careful to moderate the amount of rapidly changing pasture your horses are exposed to.  Anticipate the dangers and make slow transitions in turnout time. Weed toxicity is more likely under drought conditions, as desirable plant species are unavailable and sometimes the only green plants on the pasture are toxic weeds.  Feed horses an adequate amount of good quality hay to discourage them from eating toxic weeds under these conditions. Horses on a productive pasture tend to exercise a great deal in a normal day as they forage. When green pasture is gone, they tend to exercise less, and instead wait around in the shade to be fed. These horses are more inclined to have problems with colic than those that are out foraging.  Feed a generous amount of a bland grass hay to give these horses something to eat and be occupied with during the day, rather than waiting around for a rich feeding. Sand ingestion is more common in pastured horses under drought conditions, because horses graze grass down to short stubble, and tend to ingest more dirt or sand as they try to graze the last few short shoots and roots. Sand ingestion is a serious problem that can lead to colic and diarrhea.  Problems occur where soil particle size is large (true sand), and is not usually a problem in other soil types.  If you have a sandy soil type, prevention or reduction of sand ingestion is the most important management tool.  Feeding a psyllium product regularly may also be beneficial. Rotate pastures to try to keep drought-stressed grasses alive by not overgrazing them.  This will preserve some ground cover, thus keeping the soil together and preventing wind and water erosion and soil loss. Drought conditions drastically reduce the hay supply.  Horse owners accustomed to having a steady hay source may find that their supplier can no longer provide that. Hay prices become extremely high and horsemen often resort to buying small amounts from different sources. The greatest problem becomes maintaining hay consistency.  Radically changing feed types increases the risk for health problems like colic and laminitis.  Always try to maintain a consistent hay type, source and quality.  If this is not possible, mix the different hays to ease the transition between the types, and make the transitions as slowly as possible.  When purchasing hay from a new source, examine it carefully for mold, abnormal dust, weeds, blister beetles and sharp seed awns. A pond or stream that is used by pastured horses as a water source may dwindle and ultimately become stagnant.  In some cases, this can allow bacterial and algae growth that may pose a health risk.  Be very careful to monitor water quality in these situations and always provide extra fresh water. Wind causes stress for horses.  Blowing dust can cause eye irritation and respiratory problems, as well as just being a general nuisance.  Fly masks not only provide protection from insects, but certain types may also help protect from intense sunlight and dust.  Provide adequate shelter and clean feed and bedding to reduce dust problems.  Horses that develop coughs may need special treatment, which may include soaking hay before feeding. Certain diseases such as Dryland Distemper (also known as "Pigeon Breast" or "Pigeon Fever"), and Vesicular Stomatitis can be more common in dry, hot and dusty conditions. Know the clinical signs of these diseases, be on the lookout for them, and immediately contact your veterinarian if you see these signs develop.  Good basic husbandry goes a long way in making horses more resistant to these and all diseases. Drought has created severe wildfire risk for many areas, especially heavily wooded areas.  Horse owners that live in fire prone areas should be prepared for wildfire by having an evacuation plan.  All horse owners should have (or have easy access to) a serviceable truck and trailer that they can use quickly in an emergency.  All horses should be easily caught and should load, tie and trailer without difficulty.  If these basics are a problem, now is the time to resolve them yourself, or with help of a friend, neighbor, or trainer.  Don’t wait until you are faced with a dire emergency. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCOriginally printed in The Horse Magazine - AAEP Forum, June 2011Last Updated August 2011  
Horse Owner Self-Help: Knowing When to Call a Veterinarian Too often I have dealt with cases in which a horse owner or caretaker treated a horse incorrectly for a long period of time.  By the time I was asked to help, it was too late.  This is sad and needless. It is often difficult for horse owner's to know whether equine health problems require a veterinarian's attention or can be handled without such intervention.  Loaded with products, medications, and unreliable information, many horse owners have become misdirected in treating their horses on their own.  This problem is complicated by the fact that horse owners have a wide range of equine first-aid skills and their horses have their own unique predispositions and limitations.  While veterinary care may be needed, we all know that it is expensive and sometimes difficult to procure after regular business hours or in remote locations. The best course for everyone involved - for the horse, the owner, and the veterinarian - is early communication about the problem with your veterinarian.  Whether that communication results in an appointment will depend on the severity and type of the problem involved.  If a problem can be accurately diagnosed at the outset, an appropriate treatment plan may yield a better prognosis at less cost.  More importantly, horses are spared from needless suffering and have the best chance for a rapid and complete recovery when your veterinarian is advised of the problem at the outset. Some equine health care problems look terrible but generally heal well with minimal care.  An example of these is the common disease “Pigeon Breast” (Pigeon Fever).  This bacterial infection results in impressive abscesses on the chest and belly.  When horse owners notice these, they often panic and call their veterinarian immediately.  This problem can be serious and require some treatment, however it generally isn't an emergency requiring prompt veterinary intervention. Other conditions tend not to attract attention but can cause devastating problems.  A classic example is puncture wounds to joints and tendon sheaths in the limbs.  These may appear as nothing more than a tiny crust on the hair over a joint.  It may seem strange that the horse can hardly walk, but that tiny puncture introduced bacteria into the tendon sheath and there is a raging, closed bacterial infection of the sheath that is a painful and crippling problem.  Aggressive surgical flushing of the tendon sheath and intense antibiotic therapy is required in to attempt to treat the problem, and each day that this condition progresses untreated means a smaller likelihood that the horse will ever be sound again. ORIGIN OF THE PROBLEM I think that ultimately all of those involved want what is best for their horse. Why then do horse owners tend to treat problems themselves instead of calling their veterinarian? INFORMATION OVERLOAD. Horse owners are inundated with information on do-it-yourself veterinary care. This problem has worsened because of the unlimited information available to horse people on the Internet, much of which is unreliable. PRODUCTS. We are a society that prizes a “Silver Bullet” cure for our ills.  Similarly, horse owners tend to believe in products that claim to yield miracles.  There is little to no regulation on the animal supplement and product industry.  Most of the supplements that claim remarkable feats of healing are not supported by any credible evidence regarding their effectiveness.  Billions of dollars are nevertheless spent annually on these products. OPINIONS. One thing that is never in short supply in the equine world is opinions, and usually you get what you pay for. With good intentions, feed store staff, equestrian retailers, horse owning friends and neighbors sometimes provide medication and erroneous information to horse owners instead of referring them to their veterinarian for reliable information and education. The VETERINARY PROFESSION also is partly to blame.  We need to put more effort into educating horse owners and getting them to see that treatment of veterinary problems is more complicated than a single shot of some magic potion.  Clients often pressure veterinarians to provide drugs to them in case they have a problem.  There is often not adequate communication between client and their veterinarian regarding the correct use of the drug. Medications are sometimes used inappropriately, often to the detriment of the horse.  Laws require veterinarians to dispense prescription medications only when they have a valid VCPR "Veterinary Client Patient Relationship." ECONOMICS. Horse ownership is expensive and getting more expensive all the time.  Veterinary care is costly.  Many horse owners seek ways to minimize expense at every opportunity and it is their perception that saving on veterinary care is a good way to do this. Their perception is that by waiting and trying to treat the problem themselves, they are saving money.  This gamble can cost more in the long run and may cost the horse’s life.  See Understanding the Rising Costs of Equine Veterinary Care, for tips on how to reduce your veterinary bills while still providing appropriate care to your horse. A VETERINARIAN'S PERSPECTIVE Your equine veterinarian is dedicated to the health of horses and the education of horse owners.  Most veterinarians enjoy helping clients solve their equine health problems in the smartest and most economical way possible.  The best way for me to accurately diagnose and treat a horse is by examining it first-hand.  That said, I realize this is not always possible.  I need to be able to filter what should be seen by me from what I think clients can treat themselves.  In order to make this call, I need to know and trust my clients. I only provide prescription medications to established clients who I think have the good judgment to realize when they are in over their heads.  Clients like this have knowledge, common sense, and a willingness to place more importance on their horse’s health than on their ego.  I appreciate clients communicating with me about their horse’s health care issues early in the process and while there is still possibility to help the horse.  I want the opportunity to help determine early on whether or not the horse needs to be seen.  In some cases, after a careful discussion with these clients about the problem, I am willing to provide guidance over the phone, without seeing the horse and without the client incurring the expense of a visit.  In these cases, follow-up is vital to ensure that the outcome of treatment is as expected. WHAT YOU CAN DO Develop a relationship of mutual trust and respect with your veterinarian.  Call him or her early in the course of a problem, even one that is seemingly minor.  A call to your veterinarian does not necessarily mean a big bill, and can set you on the right course of treatment early on.  Learn as much as you can about horse health care, from basic management to the ability to recognize common health problems. This saves you money by allowing you to communicate intelligently with your veterinarian, by giving them important information.  This includes learning how to examine your horse. If you know what your horse looks like in health, you are in a better position to tell when he or she is abnormal and share these findings with your veterinarian.  At minimum, learn to competently take your horse's take temperature, pulse and respiration. Beware of erroneous information, and question alternative therapies and expensive “Silver Bullet” cures and supplements, especially when they are offered before you know what is actually wrong with your horse.  Start with your veterinarian, instead of the fancy cures.  Your veterinarian can then help direct you to sources of reliable information and effective products and services. Take advantage of our remarkable modern technology.  An example of this is e-mailing a digital photo and description of a wound to your veterinarian so that he or she can help determine whether your horse needs to be seen. Given all of the resources available to horse owners today, there is no reason for horses to suffer while owners treat them unsuccessfully for extended periods of time. Veterinarians should not be called out as a last ditch effort, only to tell a client that the problem is now beyond treatment. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
Horsemanship Tip - "Feel" This is actually not a veterinary tip. It is a horsemanship tip. Nevertheless, it may be the single most important thing I have to say about horsemanship. Ask Yourself: Do You & Your Horse Understand "Feel" May 2013 will mark 20 years that I have been in solely equine veterinary practice. Before that, I was a horseman. I had and trained a number of my own horses and had started colts for others. I started my first colt when I was 12 years old. But most of what I did with horses was essentially “blind.” I was "asleep at the wheel" and I am fortunate to still be here, given some of the stupid things I did in the name of “horse training." You hear this over and over from people who later in life see a different way to interact with horses. My profession has afforded me the privilege of touching tens of thousands of new and strange horses over those 20 years. I have asked quite a lot of many of those horses. I have asked them to tolerate me as I stuck my hands in their mouths, stuck needles in every site imaginable, cleaned and repaired painful wounds, asked them to enter dark stalls and confining stocks. I have learned a great deal asking these horses to cooperate with me in doing those things, and more and more I have studied the reactions I get from them and what those reactions mean. Through this, there is one word that means the most to me. And that word is “feel." I am not sure which of the clinician’s started using that term. Certainly this word is used by many clinicians today. Words don’t really do this communication justice. But “feel” is the word I too like to use to describe this communication with horses. Without my quest for understanding of feel, my vet practice would be much harder and less satisfying for me. Here are a few things I know about feel: The simplest way to see if your horse understands feel is to put downward pressure on the noseband of a halter. Keep modest, even downward pressure for a few  seconds. If your horse looks at you like you are crazy, braces against you or sets back against the pressure, you have not accomplished feel. Go outside right now and try it. If you can do that and your horse drops away from your lightest touch, then you and your horse get it. Now you need to be able to translate that same feel to every other thing you do with your horse, both on the ground and in the saddle. You will need to teach it in every situation. I can’t necessarily accomplish it myself, but it is the goal I keep trying to attain. 90% of the horses I touch don’t understand feel as it comes from human handlers. Some of these have reached high levels of accomplishment in their respective disciplines and still don’t get it. Imagine what could have been accomplished if their trainers/riders had been able to provide more subtle communication to those same horses. The real magicians with horses understand feel. That is why the things they do with their horses look so easy. All of today’s “natural horsemen” are using feel to accomplish the things they accomplish. Once the horse and horseman get feel, then that dialog can become so subtle that an outside observer may not be able to detect it at all.  The real fun begins in communication with the horse. 90% of the horse people out there don’t get it, and that is a shame for them, and for the horse. All of us can become better at using feel. The best clinicians in the world would be the first to say that. I try to work on it every day, with every horse I touch. I too have a long way to go. It is the journey, not the end goal that matters. Once you have the basics of feel, you have trailer loading, ground manners, and a mode of communication once you are in the saddle. Feel is calling out “Hello?” to your horse, and having them answer “Yes?” Think of it as your communication line with your horse.  It is the beginning of a real dialog between you and them, and until you get your head around what that means, your communication with your horses is just gibberish. Your accomplishment with your horse is as much luck as it is substance. Until you have it, you are shooting in the dark. Two books that I recommend, and that illustrate what "feel" means are Ray Hunt's “Think Harmony With Horses" and Bill Dorrance's “True Horsemanship through Feel." In later tips, I will illustrate "feel" with some video clips. But for today, consider buying these two books, reading them, studying them, and asking yourself whether you and your horse understand “feel." Doug Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCMarch 2013   
How to Perform Equine Veterinary Treatments Without Drama Horse owners need not have extensive veterinary knowledge or skills, however it is important for them to be able to perform basic treatments to their horse without drama.  While some horses may present a challenge in learning to accept veterinary treatments, ultimately all horses should accept all but very painful treatments in a calm and controlled manner.  They should generally accept these treatments with minimal restraint and no sedation. In this article, I discuss some of the “boring basics” of treating horses, however my priority is to emphasize that veterinary treatments need not damage the relationship between horse and handler.  Instead treatments should be looked upon as one more opportunity to strengthen that bond. Among the most common treatments that owners are required to perform on their horses are oral medication, ophthalmic (eye) treatments, wound treatments, bandaging, and intramuscular injections.  While performing these treatments is not difficult, some veterinary knowledge, good technique, and good horsemanship are all required to perform them easily and well. BASIC GUIDELINES All treatment protocols should be supervised by a veterinarian or knowledgeable technician. Be sure that you understand the instructions given for a particular medication or treatment.  This includes understanding the underlying rationale for its use. You should know the route of administration and be clear on the schedule of administration. Be sure to maintain and handle medications correctly and according to instructions.  Many medications require refrigeration or should at least be kept at room temperature, i.e. not stored in an un-insulated tack room during winter.  Check expiration dates on medications that have been in your possession for a while. Your veterinarian should make all of this very clear to you in his or her treatment instructions.  If you have any questions you should be sure to ask before you proceed. If the treatments you are performing are not being supervised by a veterinarian, you should have a high degree of confidence that the treatments are correct and appropriate. If you cannot perform the treatments on your own, ask for help. IMPORTANT PRECAUTIONS Anyone administering treatments to horses should know about some of the common pitfalls.  There is no limit to the number of things that can go wrong when working with horses, and this is especially true when performing veterinary treatments.  The following list is far from complete, but mentions a few of the common problems: Physical injury to horse or handler can occur.  Your physical safety while performing the treatment is always the most important concern, followed by the safety of the horse.  If you ever feel that you or the horse is in danger, you should stop and ask for help from someone with experience. Inappropriate use of medications can result in the death of a horse.  For example, penicillin is a very useful antibiotic in horses.  It is commonly used to treat respiratory infections.  The most common formulation is given by the intramuscular route.  It is very important that good injection technique be used.  If the drug is injected into a vessel accidentally, a serious reaction can result.  Horses having this reaction become very excitable and may even fall or have seizures.  This reaction should not be confused with an allergic reaction.  It is actually caused by a carrier of the penicillin (procaine), which causes excitation to the brain when it gets into the blood too quickly. Antibiotics given indiscriminately and inappropriately can result in severe intestinal disturbance, colic, diarrhea or even death.  Only give antibiotics under the supervision of your veterinarian. Overuse or incorrect use of anti-inflammatory medication in horses can cause fatal ulceration of the intestinal tract, organ damage and death. See my article Bute & Banamine®: What Horse Owner's Should Know. While it is commonly given by the oral route, phenylbutazone is a commonly administered intravenous injection in veterinary practice.  This is only given by the intravenous route, never in the muscle.  Phenylbutazone should never be injected by anyone other than veterinarians and veterinary technicians.  Even a small amount of bute injection that escapes out of the vein into the tissues causes severe tissue irritation and destruction.  This can lead to the skin and deeper tissue actually sloughing off. Incorrect injection technique can lead to local infection and many other problems.  I personally do not believe in teaching or encouraging my clients to give an intravenous injection.  It is a skill that is difficult to master unless it is done frequently.  Nevertheless, I do encourage my clients to learn how to give a proper intramuscular injection.  See Thal Equine Client Handout: Intramuscular ("IM") Injections for more information on proper technique. No class of drug is safe when given inappropriately. Poor bandaging technique can result in severe injury to important structures of the limb, and may even encourage the development of proud flesh.  If you aren’t sure of how to bandage, you should not do it unsupervised. Incorrect technique in applying eye treatments, or inappropriate use of eye medications can result in injury to the eye. Treatment of wounds with inappropriate topical medications can actually delay healing. BEHAVIORAL APPROACH You should think of giving veterinary treatments as an opportunity to train your horse and to improve the communication between horse and handler.  If you can easily medicate your horse, think of all the more pleasurable things you can convince him or her to do easily.  If you can give a horse sour tasting oral medications or intramuscular injection easily and without stress, you can likely teach him or her to do many other things.  If you can keep up the trust for 2 weeks of eye treatments, you are likely to be able to convince him or her that crossing a bridge or water or loading in the trailer is easy too. There is a perception that administering veterinary treatments to a horse should make him or her trust us less. When treatments are administered using common sense, good horsemanship and the right technique, the opposite should be true.  The techniques I recommend for administering any veterinary treatment are based on firm but gentle, good horsemanship.  A great horseman once said: “Make the right thing easy and the wrong thing difficult.”   This applies as well to teaching horses to accept veterinary treatment as it does to anything else we train a horse to do. A few important guidelines: Most treatments performed correctly are not very painful to the horse and should not cause aversion.  If a horse recoils in pain or react violently when a treatment is being given, it is likely that the treatment is not being performed using the best possible technique. Treatments performed using proper technique look easy and painless.  I tell my veterinary staff that any simple treatment should be performed within two minutes of entering any horse’s stall.  If not, they need to stop and ask themselves what they are doing that is not working.  If they cannot answer this and see great progress within each 30 seconds, they need to stop and ask for help. The first aspect of this system of training horses to accept medications is to use the best veterinary technique to inflict as little pain as possible. With each correctly performed treatment, a horse should become easier, not harder to treat.  If this is not the case, the person treating must look inward for the cause, not blame the horse. The approach to treating individual horses differs with breed, personality, and especially handling history.  In my opinion, all horses which can be touched with a hand can take simple veterinary treatments without sedation or heavy restraint.  Success just takes correct technique and horsemanship and variable amounts of time and patience. Before a horse can be expected to tolerate a veterinary treatment, there must be some communication and trust between horse and handler.  If oral medications need to be given to a yearling colt that has never been handled, the colt must be taught first to yield to pressure in a halter.  Before a nail puncture on the sole of a foot can be treated, a horse must learn to yield the foot to a handler and stand comfortably.  To try to perform the treatment without establishing the foundational steps will result in failure. Getting a horse to accept a treatment involves consistent application of pressure upon resistance, and release upon a “yield” or “try.”  As you are working with your horse, you are constantly communicating with him using these cues - whether or not you know it.  For example, as you put your finger in his mouth in preparation for oral medication, he pulls back.  You respond instantly with pressure on his halter.  As he yields to this pressure, you immediately release.  This approach applies to all types of treatments and training. Never start with pressure.  Always allow a horse to accept a treatment without anticipating resistance by trying to “hold him in place.”  Remember that we cannot hold a horse in place anyway, so why try? How easy you make delivering the treatment look relates to timing and consistency of the correct cues. Think of achieving the delivery of the medication or the treatment as the final step in a series of steps leading up to it.  Train each foundational step first.  For example, before squirting dewormer in a horse’s mouth, he must first accept the syringe.  Before that he should accept a finger. As with other training, you should always end on a positive note. Performing veterinary treatments on foals is different, but not necessarily more difficult than treating adults.  The techniques of restraint and the cues used are somewhat different. CONCLUSION Horse owners should be able to perform basic veterinary treatments on their horses without stress. Performing these treatments requires some veterinary knowledge, and requires good horsemanship.  All treatment protocols should be supervised by a veterinarian who has seen the horse and made a proper diagnosis. I personally enjoy the challenge of teaching horses to accept veterinary treatments in a calm and trusting way.  I see it as an extension of my horsemanship skills, which I continue to work on with each horse that I see in my veterinary practice. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Lameness & The Lameness Exam: What Horse Owners Should Know (Updated October 2014) WHAT IS LAMENESS? Lameness is a term used to describe a horse’s change in gait, usually in response to pain somewhere in a limb, but sometimes as a result of a mechanical restriction on movement.  Lameness is sometimes noticed when a horse obviously favors a limb, but can be as subtle as a small change in gait, or just a decreased ability or willingness to perform.  A horse can become lame from a variety of causes (conditions or ailments), some more easily diagnosed and treated than others. For equine veterinarians, lameness diagnosis and treatment is both a science and art.  It requires a solid understanding of equine anatomy and physiology, conformation, biomechanics, and medicine and yet it requires adaptation in response to changing conditions, horse types, uses and personalities, and owner needs. Lameness accounts for the greatest losses for the equine industry – hundreds of millions of dollars annually.  It affects individual horses of all kinds and all levels, from subtle, reduced performance to complete loss of use resulting in euthanasia.  Sadly, many horses are asked to perform when they are in pain because of a rider’s failure to recognize lameness. There is a vast amount of erroneous lameness information on the Internet, along with reliable, useful content.  Horse owners are faced with a universe of well-advertised but unproven “miracle cure” products which claim to address every ailment.  What is missing from the equation is a proper DIAGNOSIS, which only a trained and experienced veterinarian can provide. For these reasons, it benefits every horse owner and equine professional to understand the basics of lameness. I have defined 5 goals for horse people. Be able to recognize at least modest lameness in your horses. Know the most common lameness conditions and what to look for that might suggest those conditions. Recognize that worsening performance, and resistance can hint at lameness. Just because you can’t detect lameness does not mean it does not exist. Apparent back soreness can also relate to underlying lameness. Understand something about the process, and the advantages and limitations of the veterinary lameness exam. Know reasonable steps to take to minimize lameness and musculoskeletal injury in horses. A basic understanding of lameness in horses is of great value and will assist horse owners with: PURCHASE: Be able to roughly detect lameness and avoid horses that are lame. Understand the value of a pre-purchase exam, whereby an equine veterinarian assesses lameness and conformation issues, as well as the health of the whole horse, before purchase. MANAGEMENT & PREVENTION:  Recognize conformational predispositions in your horses and manage or treat for the prevention or reduction of lameness. PERFORMANCE:  Recognize, or at least suspect when lameness is the root cause of a horse’s poor performance (versus training or riding issues) so that lameness conditions can be diagnosed and treated. BREEDING:  Understanding basic equine form and function allows breeders to select horses that are of superior conformation and thus less likely to become lame. ORIGINS OF LAMENESS Lameness mostly results from pain in a location within a limb, but can also result from mechanical restrictions on limb movement. A familiar example of a mechanical restriction on the hind limb results from hamstring tear, and is called fibrotic myopathy. Lameness results from pain coming from any part of a limb that contains nerve endings.  Pain from skin wounds, connective tissue bruising, muscle pain, arthritis (joint inflammation), tendon sheath and bursal inflammation, tendon and ligament injury, and bone injury can all cause lameness. Certain breeds and disciplines develop specific lameness problems more frequently.  Two familiar examples include arthritis in the knee (carpus) in racehorses and hock arthritis in cutting horses. Lameness can also result from a mechanical impediment to a horse’s movement.  An example is what is known as fibrotic myopathy – a hamstring tear of a muscle in the hindquarters.  The scarring that results from that tear shortens the hamstring muscle unit and causes a characteristically abnormal gait. An important point about assessing lameness is that the site and nature of injury cannot necessarily be distinguished based on the appearance of the lameness. Forelimb lameness is easier for most people to recognize than hind limb lameness.  The mechanics of the forelimb causes lameness to usually be more consistent in appearance and more obvious to the untrained eye.  Hind limb lameness is generally much more difficult to visualize and diagnose.  This is especially true of subtle upper hind limb problems.  The massive musculature of the upper hind limb makes it much harder – even for an experienced examiner – to see and feel deeper structures and very difficult to image these structures using x-ray and ultrasound. A high percentage of lameness in the forelimb originates in the feet.  Upper forelimb lameness is not common in adult horses. Conformation correlates directly with the function of the limb and is closely related to the development of lameness.  Horses with poor conformation are more likely to experience problems with feet, joints, tendons and ligaments than are horses of “normal” conformation.  An example is angular limb like “pigeon toe” (toe-in at or below the fetlock level), which causes a horse to paddle when it moves and sets it up for uneven mechanical loading of the limb.  Over time this can damage the skeleton and soft tissues, causing arthritis and other problems. THE LAMENESS EXAM The lameness exam is a multi-step methodical veterinary exam wherein a veterinarian tries to determine where the pain originates.  Only by finding the pain site and alleviating the pain can lameness be properly treated.  Generally, lameness exams consist of (1) a careful history, (2) a standing exam, (3) an exam in movement, (4) flexion and hoof tester exams, (5) diagnostic anesthesia – nerve blocks, and (6) imaging the site of injury – radiographs, ultrasound, MRI and others.  The diagnosis and treatment plan is derived from a synthesis of findings from all of the above parts of the lameness exam. HISTORY: The first step in a lameness evaluation is a thorough history of both the horse and the injury.  Information gathered about the horse includes breed, age, and prior use all of which provide clues to the problem.  The history of the injury includes the date that lameness was first noticed, how severe the lameness has been, and how it occurred, if known. All of these are important questions that veterinarians ask, and horse owners should try to be as complete as possible in their responses. STANDING EXAM: A standing examination is done at a distance to evaluate the horse’s conformation and general appearance.  This is followed by more careful examination and palpation of specific anatomic structures for swelling, heat, and pain. EXAM IN MOVEMENT: The next part of the exam involves watching the horse in movement. Lameness is mostly evaluated at the trot.  Most thorough lameness exams are performed on firm to hard, consistent footing. Examination often includes circles to both directions and may include inclines or specific patterns.  For the diagnosis of some types of lameness problems, having a rider up can be advantageous. FLEXION EXAMS: Flexion exams involve putting specific joints or regions of the limb under stress for a specified and consistent period of time.  The horse’s degree of lameness is assessed before and after flexion.  The result, which is the change in severity of lameness following flexion, provides additional information regarding the origin of the pain.  As with many parts of the exam, flexion tests must be interpreted in light of what is normal for that specific horse. HOOF TESTERS: Hoof testing involves the use of a pincer-like tool to put pressure on specific regions of the foot in search of a pain response.  As with flexion exams, the key to accurate interpretation of hoof tester examination is knowledge of what constitutes a normal response.  This can only be gained through a methodical approach, and lots of experience with different types of horses and hooves. At this point in the exam, the veterinarian usually has determined which limb is lame, and may have an idea where the pain is located within that limb.  Often, nerve blocks may then be necessary to determine precisely where the pain is located. NERVE & JOINT BLOCKS: Nerve blocks are used to methodically numb portions of the limb as a means of finding the site of pain, using the process of elimination.  Also known as diagnostic anesthesia, “blocking” is the injection of a local anesthetic agent around specific nerves or into specific joints or other structures.  The horse is examined at the trot before the block, and the degree of lameness determined. Then the area in question is numbed, and the horse is asked again to trot off.  Either there is improvement in the lameness or not.  If there is not, the process is continued on specific nerves progressing up the limb until the lameness is visibly lessened.  Specific joints and tendon sheaths can also be blocked for a more specific localization of lameness.  Blocks into a joint or tendon sheath require surgical cleanliness to prevent infection of these structures. Limitations include spread of local anesthetics to adjacent regions, clouding the interpretation of the result. IMAGING THE SITE OF PAIN: Once the site of pain is located, diagnostic imaging is used to view the structures in the area and provides additional information about the nature of the injury.  This includes radiographs (x-rays) to image bone and ultrasound to image soft tissues, but may also include MRI, CT Scan and Nuclear Scintigraphy (bone scan). Radiography is generally the first approach used to image bone, but is considered less useful for imaging of soft tissues.  Radiographs are often performed in the field with portable equipment.  More difficult studies are often better performed in a clinic setting.  In the last decade, digital radiography has become the standard in equine vet practices. It does not rely on film and produces high quality images on a screen within seconds.  Examples of diagnoses that could be made via radiographic interpretation are arthritis and fractures. Ultrasound utilizes sound waves traveling through tissues to image those tissues.  It is excellent for imaging soft tissues, but cannot penetrate healthy bone. It is used commonly to image tendons, ligaments, the surfaces of bone, and other soft tissues. An example of a diagnosis that could be made via ultrasound is a tear or strain of a specific ligament. Other, more advanced and expensive diagnostics such as MRI, Nuclear Scintigraphy (Bone Scan), and CT Scan are often reserved for the more difficult to diagnose lameness cases or to provide additional information to the diagnosis.  Arthroscopic surgical exploration is an important and commonly used diagnostic that allows direct visualization of the inside of joints. See Subtle or Hard to Diagnose Lameness: What Horse Owner’s Should Know for a more detailed discussion of these advanced diagnostics. LAMENESS TREATMENTS All of the above steps, when performed properly and assembled and interpreted correctly, help to provide an accurate diagnosis and form the basis for a treatment program.  Proposed treatments will depend on the DIAGNOSIS. Ultimately, the treatment selected will depend on many factors, including the owner’s budget. Examples of veterinary treatments used to address various lameness diagnoses include: Joint (intra-articular) injections of steroids and other substances to reduce inflammation and pain in a joint. Systemic (oral or injectable) anti-inflammatories and pain relievers to manage multiple pain sources, to manage chronic pain in older or debilitated horses, and as an adjunct to more specific therapies used. Surgery, especially arthroscopy, is used to treat certain types of lameness.  The most common is arthroscopic surgery, wherein repairs are made to the joint surface through several tiny incisions, and using a tiny camera and instruments inserted into the joint. There are also a multitude of other newer therapies available including Pulsed Extra-Corporeal Shockwave, Stem Cell Injection, Injection of Platelet Rich Plasma, Autologous Conditioned Serum, IRAP and others.  These are generally classed as “regenerative therapies” wherein the body is manipulated in some way to heal itself without externally derived medications.  This is the exciting forefront of medicine and is the topic of another article. Complementary therapies like acupuncture, chiropractic, massage and other treatments may have value in some cases. CONCLUSION While lameness in horses cannot be prevented, it can be minimized through horse owner’s understanding of the factors involved in its development. Educate yourself, and work with a trusted equine veterinarian to diagnose the problem early on.  In this way, appropriate and effective treatments can be used, alleviating pain and slowing progression of problems, and enabling horses to get back to comfortable, sustainable work. While new imaging techniques add a great deal to our understanding, a methodical clinical veterinary exam will always be the cornerstone of lameness diagnosis and should precede use of these diagnostics.  While novel treatments are exciting, keep in mind that many of these treatments are in their infancy and are still unproven.  Horse owners should consider the evidence for their effectiveness before using these costly therapies on their horses.  Most importantly, recognize the value of a veterinary DIAGNOSIS. Treatment without diagnosis is usually a waste of money and resources. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated October 2014  
Maintaining the Health of Older Horses Within the practice of equine veterinary medicine, equine geriatrics has become an increasingly specialized niche that many veterinarians, including myself, enjoy practicing.  Horse owners are keeping old horses around far longer, and they are in better health than ever before.  There are many reasons for this.  These days, an owner's loyalty to their old horses outlives their usefulness as a work animal.  People have a strong emotional attachment to their old horses. They may have ridden these horses as children, or their children may have learned to ride on them.  Regardless, people tend to feel a strong obligation to provide good care to their aging equine friend during their retirement. Historically, old horses have suffered from a variety of problems as they aged.  However, better nutrition, dentistry, and a better understanding of some of the common diseases that afflict them have contributed to an improved quality of life for old horses.  In this article, I discuss some of the changes to expect as horses age, and some specific problems that develop in old horses, and how to prevent and treat those problems.  I also discuss ways to manage older horses to maximize their quality of life. THE EQUINE AGING PROCESS Horses, like people, experience deterioration of all of their body systems as they age.  Symptoms that we commonly see include weight loss, difficulty eating, and arthritis.  The immune function of old horses is not as good as it is in younger animals.   Thus, they are predisposed to disease that might not affect an animal in the prime of life. Dental disease and inefficient processing of feed is the most common reason for weight loss.  Dental problems are common in old horses and are often responsible for difficulty chewing feed and resulting weight loss. Horse’s permanent teeth are a set length. They do not grow but are gradually worn off as they grind against opposing teeth and abrasive feeds. With time, the root of the tooth (known as the reserve crown) moves down through the bone of the jaw and becomes closer and closer to the gum. So a 6 year old horse might have a 3-4” long molar, deeply embedded in bone.  A 22 year old might have a tooth that is only 1-2” long and barely rooted at all.  These teeth are predisposed to periodontal disease, pockets of feed and infection around the teeth, which lead to a variety of problems.  Often these teeth become loose and may need to be extracted.  As horses age, dental over-growths like molar hooks and long teeth and these must be addressed. The efficiency of gut function decreases with age.  Older horses do not have the same ability to digest and absorb feed that younger horses have.  This is in large part related to decreasing processing of feed by the teeth.  Having well processed, ground feed is critical to the function of the digestive tract.  The organisms that break down plant fiber are much more efficient when the particles of feed are small.  Large particles are incompletely utilized and much is just passed through in the manure.  Poor dental function also predisposes old horses to “choke” or esophageal obstruction.  Incompletely chewed feed becomes impacted in the esophagus and often requires veterinary attention.  For these reasons, attention to nutrition, management and dental care are critical aspects of caring for old horses. Also, like humans, horses are at risk for a variety of tumors (cancer).  Cancer is much more common in old horses than people realize.  Equine melanoma is a unique problem occurring in older gray horses.  We expect to see these characteristic hard bumps and masses around the anus, tail, mouth and the back of the jaw in old gray horses, and usually only take note of their size and periodically monitor them.  In a small percentage of horses, though, melanoma can actually become a life threatening problem that can be difficult to treat.  Many other less common cancer types affect horses.  All told, cancer is a significant cause of death in old horses. Equine Cushing’s Disease, also known as Pituitary Pars Intermedia Dysfunction (PPID), is still an under-diagnosed problem in older horses.  In fact, PPID is an extremely common problem in old horses and should always be considered as possibly underlying other problems like laminitis and persistent infections.  PPID results from an overgrowth of part of the pituitary gland in the brain.  Many horse owners have heard of this disease and associate it with a curly, long coat and abnormal shedding patterns.  However, horses can have this disease without showing these classic outward signs.  Often horses with normal coats are affected to some degree by PPID.   While all body systems are affected by this disease, the most serious complication is laminitis.  Diagnostics and treatment for this syndrome have improved tremendously in recent years. I enjoy diagnosing old horse with this problem because I feel that in many cases, I can dramatically improve their life by making a diagnosis and start an appropriate treatment plan. See Cushing's Disease/Syndrome - PPID & EMS: What Horse Owners Should Know for more details.  Chronic pain is a major problem for old horses, as it is for old people.  Arthritis is the most common source of pain. This usually is chronic and often affects the carpus (knee) and lower limb joints.  Proper diagnosis and treatment of this pain also improves the quality of life for horses.  Chronic pain can also play a role in weight loss. In many old horses, there is a combination of many of these factors that contribute to a poor quality of life.  When we address these underlying factors, we can really improve their lives.  As with most veterinary problems, good preventative care is better than being forced to treat these problems once they occur.  Good care through the early and middle years helps prevent many problems and sets an old horse up to have a healthy and comfortable retirement. MANAGEMENT & CARE There are now many pelleted “senior feeds” that are balanced and easily digestible nutrition for the older horse. Many of these commercial feeds provide everything an old horse needs.  As a horse owner, it is important to be aware of these feeds and ask your veterinarian how incorporating these feeds into your horse’s regimen can help his quality of life.  We use Purina's Senior Feed in our practice and have found it to be a good overall source of nutrition for older horses and other convalescing cases. Old horses benefit from consistent moderate exercise in the form of pasture turnout or regular light to moderate work. This is, of course, provided that they are not in pain.  Vaccination remains an important part of preventative medicine.  My recommendation is to vaccinate older horses only for those diseases for which they are really at risk.  The incidence of adverse reactions to vaccination is higher in older horses in my experience.  A well designed and consistent parasite control program is also essential since older horses are very susceptible to parasites. CONCLUSION Maintaining a high quality of life for old horses is now very possible.  Horse owners should understand as much as possible about the equine aging process and diseases affecting old horses.  Providing good consistent care to horses through their early and middle years is critical in preventing many common problems of old age.  Your equine veterinarian is the person who can help you design a management plan for each stage of your horse’s life. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Parasite Management In Horses: A New Paradigm Internal parasites can cause serious disease in horses without leading to external signs obvious to horse owners.  Parasite eggs and worms are tiny or microscopic and rarely visible in manure.  Significant parasite loads cause all sorts of problems for horses.  They can reduce immunity, cause gastrointestinal irritation and damage, reduce nutrient uptake and cause generalized unwellness. While these “hidden” problems are more common, parasite damage can also lead directly to colic and death. Because of their hidden nature and their great impact on horse health, it is very important for horse owners to have a general understanding of the complex nature of equine parasitism and take an intelligent approach to parasite control.  In the last few years, evidence for worm resistance to common dewormers has emerged.  This is a serious problem and requires a re-examination of our current methods of parasite control in horses. ABOUT THE PARASITES There are more than 150 species of internal parasites that afflict horses.  Some frequently discussed groups include: Ascarids (Roundworms) Large strongyles (Bloodworms) Small Strongyles Pinworms Bots Tapeworms Lungworms Internal parasites have a life cycle that involves stages within the horse, and stages in the environment.  Parasites released into the environment take time to develop to infectious stages.  The climate and season are key factors affecting the survival and development of these stages.  Management must take into account the life cycles and the geographic region’s climate. Most species have stages (eggs or larvae) that are passed from horse to pasture in manure.  Any or all of these parasites may be present in the horse at one time, but they may be at different stages in their life cycles.  Some worm species can lay hundreds of thousands of eggs per day, so parasite loads can grow quickly both on pasture and in horses.  The different dewormers have varying effectiveness against the types and stages of parasites.  Intelligent control of parasites must take all these factors and many others into account. PARASITE DAMAGE Different parasites harm the horse in different ways, depending on their location within the horse and life cycle.  Some parasites cause severe, life threatening damage.  An example is the large strongyle, the adults of which localize in the large arteries supplying blood to the intestine.  These worms cause damage to the arteries and result in loss of blood supply to segments of intestine, a potentially fatal problem which results in colic signs.  Certain parasites damage vital tissues like lungs or liver.  This usually occurs as larval stages migrate through the horse's system to complete their life cycles. Parasites can cause obstructions and ulcerations within the horse's digestive tract.  The most common example of this is obstructions caused by large roundworms in young horses (Ascarids).  Bot flies cause irritation to skin as they lay eggs.  Pinworms cause skin irritation and itching to the area around the anus and tail head.  The most common species of Tapeworm lives in a specific segment of small intestine and causes irritation and blockage at that site.  Lungworms are common in donkeys and cause clinical signs of coughing, usually in horses stabled with donkeys.  These are just some examples of the many syndromes that parasites can be involved in. More common than the obvious diseases discussed above is low-grade disease in horses that might otherwise appear to be perfectly healthy.  Signs of infestation may include: Dull, rough hair coat Lethargy or decreased stamina Weight loss Coughing and/or nasal discharge Tail rubbing and hair loss Resistance to the bit due to mouth lesions Colic Summer sores Depression Loss of appetite General unwellness or loss of condition Diarrhea THE PARADIGM SHIFT Over the past half-century, deworming compounds have been developed which have drastically reduced parasite problems in horses.  This has been a blessing for horse health.   There are far fewer severe parasite-related problems than there were before.  There have been several main “chemical classes” of dewormers that have been developed over that time. However, parasites have gradually developed resistance to these compounds, resulting in their growing ineffectiveness. Recently, researchers have shown that this resistance is a greater problem than we thought, and that it is progressing rapidly.  We are beginning to see resistance to even our newest and most potent chemical class.  Before the advent of paste dewormers, veterinarians were very involved in equine parasite control.  Veterinarians typically tube wormed horses, meaning they passed a stomach tube and dosed a large quantity of the chosen chemical directly into the stomach.  In the last 25 years, paste formulations of the common chemical classes have become increasingly available and very cheap, especially through the Internet. Many horse owners rotate dewormers casually, not understanding the problem.  In my prior deworming handout, I recommended that a variety of dewormers be rotated.   In light of parasite resistance, these recommendations need to be reexamined.  Misconception and lack of awareness by the whole industry has led to the development of a very large problem. It is now time for veterinarians to become involved again in parasite control, with emphasis on targeted deworming. THE PROBLEM WITH THE OLD PARADIGM We have learned certain things about equine parasites from doing fecal egg counts.  We learned that we can make the worms disappear from the manure by using these compounds.  We assumed that if we rotated compounds, that parasites that were not killed by one class, would be killed by the next.  This idea worked well when the 3 main chemical classes each killed the majority of parasites.  However, in the last 10 years, this has proven to no longer necessarily be true. KEY POINTS: Two out of three main classes of chemical no longer kill parasites adequately.  Parasites have become resistant to them.   Their continued indiscriminate use will only quickly result in complete resistance. Rotation using ineffective compounds ensures complete resistance to them while creating a false sense of security.  The effective dewormers “cover up” the inadequacy of the others in the rotation. We are already seeing pockets of resistance to ivermectin and it is inevitable that this will increase.  Moxidectin (Quest) is a related compound.  It is only a matter of time before we see resistance to it too.  Use of these compounds without fecal testing will ensure a short effective life for them. There are no new chemical compounds in the works right now.  Research and development is costly and takes time.  Our emphasis should be on extending the effectiveness of what we have. UNDERSTANDING PARASITE RESISTANCE Parasites develop resistance to the chemicals used to kill them.  Resistance is based on individual worm genetics and selection for these genetic traits, i.e. natural selection.  Most parasites are killed by a properly administered and effective dewormer.  Out of thousands of worms, there may be a few surviving (resistant) parasites that have genetic differences that allow them to tolerate the chemical. These few survivors can then occasionally interbreed with other similarly resistant parasites, leading to a higher number of resistant parasites in the next generation.  These offspring survive and propagate, and in the next generation there are more resistant parasites. The process is invisible to the horse owner.  The more of a chemical there is in the environment, the greater the pressure for the parasite populations to develop resistance against it, and the faster the percentage of parasites becomes the new resistant type.  Indiscriminate dewormer use has and will accelerate the onset of resistance.  It is inevitable that this process will take place with enough time and exposure to these compounds.  Our goal should be to make that period as long as possible for each of our dewormers.  How do we achieve this?  By minimizing the exposure to these compounds through targeted deworming. LIMITED DEWORMING & INCREASED FECAL SAMPLE TESTING The best way to prevent development of resistance to these compounds is not to use them at all.  That would completely eliminate any selective advantage to resistance.  Obviously this is not feasible because our horses would again succumb to the effects of parasites.  However, leaving a segment of the parasite population with minimal exposure to these chemicals will slow resistance.  Those susceptible parasites are allowed to go on living and competing with those that have developed resistance.  This is known as preserving “refugia” within the population. We can move toward this concept by only targeting those horses that have higher fecal egg counts.  For the others, we would drastically reduce the number of deworming treatments.  This requires knowing which horses have higher worm burdens and shed more into the environment.  This knowledge requires fecal testing.  By using fecal egg count results, horses are broken into 3 groups, those with high parasite burden and shedding into the environment, those with moderate, and those with minimal.  Only those in group 1 are dewormed frequently.  The others are dewormed far less.  The goals of this new approach are optimal horse health for all horses in the herd, reduced dependency on chemicals and reduced contribution to the resistance problem, and improved fecal diagnostics to monitor the effectiveness of the program. The key to this new approach to deworming is working with your veterinarian.  It is no longer acceptable to randomly treat horses or keep horses on a typical deworming rotation calendar. There is no perfect dewormer and no standard program.  Fecal testing guides the program. Horses at different ages and stages have varying needs for parasite control.  20% of horses in a group shed 80% of the total parasites. Young, growing horses have some special needs.  Young foals are especially susceptible to ascarid (roundworm) infestation, and may benefit from deworming with an appropriate compound at 30-60 day intervals until they build some natural resistance. Climatic conditions and season of year influence parasite levels in the horse and on pasture and are critical factors to address. The goal is not to kill all parasites, but to keep parasite loads to a level compatible with health, and leave a reservoir (refugia) of parasites in as many horses as practical. Based on this new paradigm, we recommend a fecal exam on every horse at least once annually.  This is the only way to determine the effectiveness of a parasite control program and to detect the development of resistant parasites. YOUR ROLE Collecting a fecal sample is easy, simply pick up 1 fresh fecal ball in a zip lock bag, label it with your horse's name, and drop it by your veterinarian's office.  You can store a fresh sample up to 12 hours if you keep it refrigerated.  At our clinic, we do this testing in-house.  In 24 hours, we will give you a result. The sample must be taken at least 8 weeks after deworming, or 12 weeks after deworming with a Quest compound.  Otherwise there is still effect from the prior deworming. If horses are on a continuous dewormer like Strongid C, they can be tested at any time. YOUR VETERINARIAN'S ROLE Perform a fecal egg count on these samples and determine which horses are low (< 200 epg), moderate (200-500 epg) or heavy (>500 epg) shedders. The specific parasite species are identified. From this, a determination can be made of the most effective deworming compound. We then have you deworm the horses with the appropriate compound. Two weeks later, fecal samples are again taken.  The veterinarian performs a Fecal Egg count reduction test.   This is a retest of a manure sample 10-14 days after worming with the recommended compound.  Depending on drug class and degree of resistance, there are accepted ranges for the reduction percentage.  It should be more than 95%. A customized approach is then tailored to the situation.  Horses are dewormed with the appropriate compound based on their category.  Low shedders are dewormed once or twice annually, spring and fall.  Moderate shedders are dewormed three times annually.  Heavy shedders are dewormed 4 times annually. Testing is recommended at least annually. Routinely deworming horses every 8 weeks will become a thing of the past. The cost of testing should be offset by big savings in the purchase of deworming compounds. DEWORMING COMPOUNDS Currently used deworming compounds can be divided into three basic groups effective against worms other than tapeworms and one compound specific to tapeworms: Benzimidazole Products.  The oldest class and that with the highest resistance in small strongyles.  Examples include Oxibendazole (Anthelcide EQ) Fenbendazole (Panacur, SafeGuard). Pyrantel Products.  Less resistance but a rapidly growing problem.  Examples include Strongid paste, Strongid C, Rotectrin 2.  These have some effect against Tapeworms. Ivermectin/ Moxidectin.  Two related compounds.  We are seeing the beginnings of resistance problems but these are still very effective against a wide variety of parasites. These products kill Bots in the stomach.  Moxidectin is the newest deworming compound, has the fewest resistance problems, and kills encysted small strongyles. Praziquantel.  This compound is specific to Tapeworms, which are not killed by the above compounds.  Praziquantel is added to one of the others to kill tapeworms. METHODS OF DELIVERY Oral paste syringe or liquid is most common method of dewormer delivery.  Deworming pastes and feed formulations have been the foundation of deworming programs because of convenience, cost and ease of administration. It is vital for horse owners to understand that there is a big difference between trade names and active ingredients. Tube deworming is performed by a veterinarian using a rubber naso-gastric tube.  It is less frequently used now but for many years was the preferred method.  The technique still has its place and is highly effective because it allows a large dose of chemical to be delivered into the stomach at once.  There is minimal temporary discomfort for the horse as the tube is passed through the nostril and down the esophagus into the stomach.  Because of the skill required, this procedure should be performed only by a veterinarian. Daily deworming with a feed supplement, most common is Strongid C.  Continuous dewormers like Strongid C (pyrantel) are still frequently used and tend to be highly effective in decreasing worm loads in horses and on pasture.  They work by inhibiting the larval stages of many worm species. It is recommended that horses on Strongid C still be dewormed with either Ivermectin or Moxidectin, with Praziquantel, in the spring and late fall.  This is primarily to kill bots and tapeworms not affected by the Strongid C.  Horses on Strongid C should have fecal testing performed 1-2 times per year to assess the effectiveness of the program.  Horses are tested while on this supplement. There is a strong argument, however, that Strongid C is contributing to the problem with pyrantel resistance and should be discontinued. All three methods are effective and likely have their place in the new paradigm.  The key is that the deworming product must be given to the proper horses, in the proper dose, at the proper time. Decisions must be guided by testing. Administration must be such that the animal actually ingests the required dose. ADDITIONAL POINTS TO CONSIDER Any deworming today should be based on fecal exam results. Some horses may find pastes unpalatable and spit them out.  It is best to dose before feeding because horses with feed in their mouths can more easily spit out the paste. Some horses are considered difficult for owners to deworm.  Any halter trained equine can be taught to easily accept dewormers if the right technique is used. Your veterinarians can advise you if you have any questions.  See Thal Equine Client Handout: Giving Your Horse Oral Medications for more details. It is critical to get the correct dose to the stomach.  Under-dosing is ineffective and contributes to parasite resistance.  It is best to err on the side of a very slight overdose, with all compounds except Quest. For Quest products, the dose must be calculated based on the horse's weight, as overdose is possible.  Overdose is unlikely with the other products.  While Quest products are very effective, I do not recommend them for horses less than 2 years or under 600 lbs.  I personally do not use these products in pregnant mares either, although they are likely safe. Products with Praziquantel are available and have excellent effectiveness against tapeworms and should be used as directed. Alternative dewormers like diatomaceous earth: I have personally seen horses on these products that still have a high parasite load.   As of now, there is little published evidence for their effectiveness.  That is not to say that there aren’t natural compounds, which might prove very beneficial.  But I would like to see the research before I recommend relying exclusively on such alternative approaches. Remove bot eggs regularly from the horse's hair coat to prevent ingestion.  Bots generally do not cause serious disease but if they can be removed it means less will be ingested. Foals should be dewormed the first time at 4 weeks of age, then every 4 to 6 weeks until they are a year old with a compound that kills ascarids (oxibendazole).  After that, they are monitored with fecal egg counts and treated as adults. Pregnant mares should be dewormed with a safe product a few weeks prior to foaling to decrease the foal's exposure to parasites, unless they are ill or have complicated pregnancies. PASTURE & STABLE MANAGEMENT Importantly, chemical control is actually the less important part of a total parasite control plan.  Since parasites are primarily transferred through manure, good stable and pasture management is also key.  With this in mind, I suggest the following: Pick up and dispose of manure from stabled horses on a frequent basis. Horses in growing pastures tend to defecate in certain areas in the pasture (the roughs) and graze in between these (the greens).  This is likely an adaptive behavior reducing ingestion of parasite eggs.  Keep this in mind given your management of the pasture. When possible, use a feeder for hay and grain rather than feeding on the ground. Harrowing pastures regularly may break up manure piles and expose parasite eggs and larvae to the elements, but may also spread viable eggs out onto the grass so that horses are forced to ingest more parasites.  My recommendation in this area is to only harrow horse pasture when the weather is hot and dry during the peak of the summer, then to allow several weeks for the parasites to die before putting horses out. While eggs may be slow to develop to infective stages in cold weather, they often survive, awaiting the right conditions.  Many parasite eggs survive on snow and ice for the winter and may resume their life cycle in the spring. Spreading manure on pastures without first composting it will spread parasite eggs on the pasture and can lead to heavy pasture contamination and re-infestation. Composting requires watering (in our climate) and turning of piles.  Properly done, this leads to intense heat production and killing of most parasites.  With proper management, composted manure can be returned to the land and benefit it. Rotate pastures by allowing other livestock, such as sheep or cattle to graze them.  This interrupts the life cycles of equine parasites. Group horses by age to reduce exposure to certain parasites and maximize the deworming program geared to that group. Keep the number of horses per acre to a minimum to prevent overgrazing and reduce the fecal contamination per acre, or use rotational grazing. CONCLUSION In the past, it was taken for granted that frequent rotational deworming was the best way to reduce parasite resistance.  While rotation has its place in the new paradigm, we are learning that there is more to it than that.  Parasite resistance is a real and growing threat.  It is a problem that veterinarians and horse owners need to work together to manage.  Resistance is inevitable but our goal in changing the paradigm now is to slow the problem, and extend the period of effectiveness of our currently effective compounds. ReferencesKaplan, Ray DVM PhD.  An Evidence Based Medical Approach to Equine Parasite Control , in “The Practitioner” October 2008; Briggs, Karen, Reinemeyer, et al. Parasite Primer series in “The Horse” 2004; AAEP Pamphlet on Parasite Control, 1998; Swiderski, Cyprianna DVM PhD, French, Dennis D. DVM DABVP Paradigms for Parasite Control in Adult Horses in AAEP Proceedings 2008. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011    
Post-Breeding Endometritis: A Common Cause of Reproductive Failure in Mares Young mares and mares with healthy reproductive tracts usually conceive easily and carry a foal to term without difficulty.  Attempts to get some older mares and mares with reproductive problems pregnant can be very frustrating and costly.  In this article I discuss a few of the factors that result in uterine problems.  I then describe the diagnosis, treatment and management of mares with post-breeding endometritis, the most common cause of mare infertility.  Understanding the basics of how the equine reproductive tract functions will help you to understand the problems that can develop. THE EQUINE UTERUS The uterus is a muscular, hollow organ with a lining that is designed to attach to a placenta and provide the nutrients needed from the mare to sustain a foal.  The uterus is protected from the outside world by several barriers to infection.  The vulva forms a tight seal and helps to keep contaminants out of the vagina and uterus.  The cervix is a thick tube (separating vagina from uterus) that tightens when a mare is out of heat and softens and opens during the heat cycle. Mares cycle regularly during the spring summer and early fall and go into a period of reproductive quiet during the winter months.  In a normal mare, there is delicate communication between the ovaries, cervix and uterus.  This communication functions to allow fertilization to take place, then switches gears and provides an environment for the embryo to grow.  Any disruption of this complex process results in failure to conceive or failure to maintain a pregnancy to term. Estrus (heat) in horses lasts about 7 days out of a 21 day cycle.  During heat, the cervix is open and the uterine defenses are primed.  The uterus is ready to receive sperm and fight off infection. The ovaries produce follicles (bubbles on the surface of the ovaries containing the ova or eggs) that grow in size over the 7-day period until ovulation (rupture of the follicle) takes place at the end of estrus.  The egg resulting from the ovulation passes into the oviduct, a thin tube leading to the uterus. Each time a mare is bred, sperm is deposited directly into the uterus, and migrates within four hours up to the tips of the oviducts, where it waits for the arrival of the egg at ovulation.  Sperm can survive for days here.  Once ovulation takes place, these sperm are in a position to fertilize the egg.  The now fertilized egg (embryo) stays in the oviduct for about 6 days before entering the uterus.  At this time it migrates slowly back and forth from tip of one uterine horn to the tip of the other, before attaching to the uterine wall at about day 16. The uterus of a pregnant mare is sterile, there are no bacteria present. When a stallion breeds a mare, there are huge quantities of debris and bacteria brought into the uterus along with the sperm. The mare must be able to take the uterus from this state of contamination to the clean state necessary to support the young embryo when it arrives 6 days later.  How it does this is a miracle! Millions of inflammatory cells recruited to the uterus during estrus devour bacteria and debris.  Strong muscular uterine contraction expel fluid, dead sperm and debris from the uterus through the open cervix.  Once this cleanup process takes place, the uterus is guarded by several barriers to infection.  The tight, closed cervix and the vulvar seal protect the uterus through pregnancy from contamination from the outside world. Post-breeding endometritis (mating induced endometritis) is the most common causes of mare infertility. It is inflammation of the inner uterine lining, or endometrium, following breeding.  Older mares and mares with poor uterine function commonly have this problem. In older mares, there is loss of muscular function, and the uterus often lies in a lower orientation in the abdomen, making clearance of fluid and debris more difficult. While bacteria can be involved in this problem, they are more often not the direct cause.  Sperm themselves, along with the other products introduced into the uterus at mating, induce a strong inflammatory response in the normal uterus.  In a normal mare though, the uterus has resolved this inflammation after 24 to 48 hours.  In a mare without the ability to clear the uterus, there is still inflammation and irritation going on when the embryo arrives.  This is often recognized on an ultrasound by accumulation of fluid in the uterus.  In normal mares, this fluid is cleared by 24 hours after breeding.  In abnormal mares, there is still significant fluid accumulation at this stage. Severe scarring of the uterine lining may result from ongoing, untreated endometritis. This may ultimately make the uterus incapable of supporting a pregnancy to term, and make the mare irreversibly infertile. THE VETERINARY DIAGNOSIS The main tools used for diagnosis of breeding problems in the mare are rectal palpation, ultrasound, uterine culture, cytology, biopsy, and the cervical exam. Ultrasound through the rectal wall allows detailed visualization of much of the reproductive tract.  It is especially good at detecting even small quantities of fluid within the hollow center of the uterus.  Fluid accumulation found during estrus (and more than about 8 hours after breeding) is a good indicator that treatment will be necessary to achieve pregnancy. Uterine culture identifies bacteria, which may be significant in the uterine inflammation.  Cytology is the study of the cells collected by swabbing the inside of the uterus and is used with culture. Uterine biopsy is a vital diagnostic tool.  It requires the use of a long handled instrument to take a pinch of tissue from the inner uterine lining.  This tissue is examined under the microscope to determine the nature of the problem and to determine whether or not the lining is suitable to maintain a foal to term. TREATMENT One goal is to breed mares as few times as possible in the heat cycle, at just the right time, which is usually toward the end of heat. The idea is to get adequate sperm up in the oviducts, where it is ready to fertilize the ovulated egg, while introducing as little foreign material into the uterus as possible.  Because the sperm migrate to the tips of the horns, we are able to lavage (flush) out the debris from the uterus 4 to 12 hours after breeding without flushing the live sperm out.  This cleans up the uterus, allowing the embryo to migrate into a hospitable uterine environment.  Sometimes the mare is lavaged before breeding as well. Drugs are often used which cause the uterus to contract, forcing the fluid out.  Some mares require treatment with uterine antibiotics.  Mares with vulvar conformation problems may need a Caslick's operation to restore the barrier function of the vulva.  Mares with cervical problems will need to have those addressed as well. GENERAL TIPS TO PREVENT BREEDING PROBLEMS IN MARES It is always easiest to attempt to breed young mares that are reproductively healthy. Buy mares with the reproductive history and conformation to be easy breeders. Learn as much as possible about equine reproduction so that you understand the process and can make good decisions. Breeding old, maiden (never bred) mares is difficult. Try to breed maiden mares before 10 years of age if possible. If you have a mare that does not breed, immediately seek the advice of a veterinarian who is experienced in managing problem mares. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
Preventing or Addressing Weight Loss in Horses Clients often bring horses to our veterinary practice with a complaint of weight loss.  In my approach, I start by determining whether the horse is really underweight.  Whenever I think about changes in body weight, there is a specific thought process I use to identify the reasons for it.  This approach is based on an understanding of the balance between a given horse’s energy intake and energy output.  Keeping this in mind, I look at all of the factors that contribute to nutrition and intake on one hand, and energy expenditure on the other. By understanding this important balance and the factors that affect it, keeping horses at optimal weight and health is easier and more intuitive and, in cases of weight loss, can be better understood and resolved. BODY CONDITION SCORING (BCS) In order to determine whether a horse is underweight or not, it is first important to know what their optimal weight should be.  This is a very subjective assessment.  The closest we can come to making an objective judgment is through an established Body Condition Score System, which rates horses on a scale of 1-9.  On this scale, 1 is emaciated and 9 is obese.  Body condition scores of 5 to 6 are considered optimal.   This system is based on assessment of the muscle and fat that cover of the bony landmarks of the body, especially of the top-line and ribs. Information on body condition scoring is readily available on the Internet, and I recommend that horse owners familiarize themselves with it and use it.  Scales for horses are generally not easily accessible.  Weight tapes measure the circumference of the girth and relate that to weight.  They are a cheap and practical alternative to a scale and are especially valuable for tracking change.  For the purposes of this article, I consider significant weight loss to be a state where horses fall out of the optimum range (5-6) of Body Condition Score System. WEIGHT LOSS Weight loss results from an imbalance between caloric intake and expenditure of energy.  Factors that affect either or both intake and outflow will change the balance and affects a horse’s weight.  If there is more energy expenditure than caloric intake, then a horse will lose weight. Let's first discuss expenditure of energy.  How much energy a horse expends depends first upon the amount of energy needed for maintenance.  This depends on body weight and metabolic rate.  Different breeds and individuals have varying basic nutritional needs for maintenance.  The amount of feed necessary for maintenance of a typical “hotblood” like an Arabian or Thoroughbred tends to be greater (per unit body weight) than that for a typical “coldblood” like a draft or pony breed.  Beyond energy for maintenance is that needed for additional body functions including: Late term pregnant and lactating mares require maintenance plus the additional energy needed for growth of the fetus or the production of milk. Horses in work expend additional energy in proportion to how much work they do. Growing foals require the energy for maintenance plus the energy needed for growth. Weight loss results from the breakdown and conversion to energy of complex sugars, muscle, and fat from the body.  This breakdown is intricately controlled by a complex system of chemical messengers responding to the body's perceived needs.  Expenditure of energy must be balanced by energy intake in the form of nutrition, or signals are sent to start to break down the body’s stores of complex sugars, muscle, and fat to account for the difference in needed energy, resulting in loss of these tissues and weight loss. Nutritional intake is how much nutrition is brought into the circulation from the intestine, and this relates to what is taken into the body from the diet. There are several steps that are critical for a horse to achieve necessary nutritional intake.  A horse must have access to and ingest an adequate amount of high quality feed of the appropriate type.  He must be able to process this by proper grinding of feed by the teeth.  Poor dental function results in poorly processed feed, which is not well digested and absorbed in the intestine.  A healthy gut assimilates the needed nutrients into the bloodstream. Healthy body systems and metabolism results in the nutrients in the bloodstream being processed, with the necessary energy used and the remainder put into body stores in the form of complex sugars, muscle and fat.  Anything that decreases nutritional intake, with all else being equal, will result in weight loss.  Therefore, the most common reasons for weight loss in horses are: Inadequate feed intake or feed quality mismatched to nutritional needs. Inadequate processing of feed resulting from dental problems. Parasite infestation.  Parasites compete for nutrition and cause damage to the intestinal tract, which decreases absorption of nutrients. Aside from dental abnormalities, older horses simply have more difficulty assimilating nutrients from their intestinal tract.  For that reason, they require more easily digestible and absorbable feeds. Disease and chronic pain.  Sick animals lose weight because energy is needed to heal or fight infection, this is often made worse because they tend not to eat as much. Animals that are in chronic pain also lose weight.  Tumors are a common cause of weight loss in older horses.  Many tumors secrete substances that directly cause weight loss by breaking down body stores of energy. MANAGEMENT & FEEDING SUGGESTIONS Start by being able to define your horse’s body condition using the Body Condition Scoring System.  Keep in mind that it is more difficult to assess body condition in the winter, when hair-coats are long.  Feel your horse’s body, especially his top-line and ribs, through the thick coat to get a better assessment. When designing a feeding program, keep in mind the basic metabolic differences among breeds and individuals.  A young Thoroughbred race horse will be a much “harder keeper” than a 10 year old Pony gelding.  Within breeds, certain individuals will be harder keepers than others.  The basis of most equine feeding programs is good quality forage or hay.  Many idle horses without special needs maintain their weight well on grass hay alone.  For others, it will be necessary to account for extra needs when calculating the feed necessary for a given horse. Think of the feed needed for maintenance, then add in additional feed to account for these additional factors. For horses that have needs beyond maintenance, additional energy rich concentrates (grains) and other special feeds may also need to be added. Calorie-rich supplements like corn oil or rice bran may be added as recommended by your veterinarian.  There are now many commercial diets available for horses with almost any special need. Horses in work usually require more energy rich feeds (concentrates) to keep their weight. Old horses often need to be fed special easily assimilated “senior" feeds. Foals must be fed more to account for growth. Breeding stallions, late term pregnant mares and lactating mares are all fed to account for their additional energy expenditures. If horses are fed in a group, be sure that each horse gets the feed he needs. Submissive horses in a group are often driven off of feed. These horses lose weight while others in the group become fat. The way to handle this is to segregate compatible horses and horses with similar nutritional needs into groups.  Observe individual horses for weight changes carefully so that any management changes can be made early.  Certain hard keepers may need to be fed separately. In all cases, make all feeding changes slowly to avoid digestive upset and other health problems. It advisable to lower carbohydrate and increase fat as a source of energy in the diet whenever possible. Continually monitor your horse’s weight, and make changes to feed and management as needed. It takes very cold weather to change the amount of feed necessary for a healthy horse.  This is usually not a big consideration in our area.  See Winter Health Care Basics for Horses for more information. Maintain all horses on an appropriate parasite control program. Keep all horses in good dental health.  I recommend an annual or semiannual dental exam by an equine veterinarian. Work with your veterinarian to identify and treat underlying health problems causing weight loss. CONCLUSION Maintaining optimal weight and preventing weight loss in horses requires a balanced approach.  Your veterinarian can help you take into account all of the factors we have discussed to arrive at an effective management program for your horses.  I feel that the best way to accomplish this is through annual or semi-annual veterinary visits and consultation. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Sand Accumulation in the Colon: A Common Cause of Equine Colic Most horses live long and healthy lives with small amounts of sand and dirt in their intestine. As they eat, horses naturally pick up small amounts of soil, which usually moves through with other feed material and causes no problems. Horses accumulate sand in their intestine by eating off of sandy ground, or grazing short stubble on sandy soil. The most important factor determining whether or not a problem develops is the soil particle size at a given location. Unlike sand, fine clay and silt soils usually do not accumulate.  Sand grains are larger than those of silt or clay, and their heavier weight causes them to settle to the bottom of the intestine rather than pass through. If sand intake becomes greater than outflow, then accumulation begins.  Over time, horses can accumulate huge quantities of sand, mostly in the large intestine (large colon).  I personally have removed up to 100 lbs. of sand from horses at surgery. Large accumulations of sand lead to diarrhea, weight loss, colic, and potentially to life threatening obstruction. Sand causes intestinal pain and damage by a variety of effects. The sheer weight of the sand pressing down probably causes decreased blood flow to the colon wall. Gritty sand probably also causes abrasion to the intestinal lining. The damaged colon wall also loses the ability to absorb nutrients and reabsorb water, causing diarrhea.  Sand may combine with feed to create an obstruction that physically blocks movement of feed material in the colon. Stretch from impaction and gas distension of the gut causes gut damage in itself, which further reduces function and leads to more distension and sand accumulation. A cycle of damage and dysfunction can develop. Toxins (endotoxins) sometimes are taken in from the damaged gut into the circulation, causing problems like laminitis. The colon can further displace or twist, resulting in an immediate life-threatening crisis only solved by rapid surgical intervention. In the worst-case scenario, the colon wall may become so damaged that it ruptures, spilling manure into the abdomen and causing rapid death. SIGNS OF SAND ACCUMULATION Diarrhea and/or colic are the most common signs of sand accumulation. Horses with sand accumulation may be depressed and eat less than normal, and can also experience weight loss and fever. Colic (abdominal pain) is demonstrated by generalized restlessness and apparent discomfort, lying down, kicking at the belly, pawing, sweating, looking at the side, rolling or any combination of these signs and many others.  Diarrhea is the most common and “classic” sign of sand accumulation in the horse. Horse owners should recognize diarrhea in the adult horse as a medical emergency. DIAGNOSIS Your vet differentiates sand accumulation from other causes of diarrhea and colic with a thorough examination and diagnostics. A familiar method used to diagnose sand is hearing it in the colon with a stethoscope. Fluid and feed washing over sand sounds like waves washing over sand at the beach. An important part of the veterinary colic examination is rectal examination. Your vet might feel a feed impaction in the colon which accompanies sand accumulation. In serious cases, they might even notice obvious grit in the rectum. Another helpful diagnostic tool is radiography (x-ray). The minerals in sand show up brightly on an x-ray. Unfortunately, for an animal as large as a horse, sufficient penetration of the abdomen requires a very powerful x-ray generator not available in most equine hospitals. Ultrasound examination of the belly also can help identify sand. A simple diagnostic tool that you can use is the “glove test.” Collect a handful of manure and place it in a clear plastic glove, plastic bag or jar. Add water, thoroughly mix it with the manure and allow the contents to settle. If a significant amount of sand settles to the bottom, it is reasonable to assume that there is significant sand in the colon. TREATMENT & PREVENTION The goals of veterinary treatment of horses with sand accumulation revolve around pain relief and nursing care to support the body systems, while high doses of psyllium (often given by stomach tube) begin to move the sand out.  It may take weeks for the intestine to completely “clear” of sand. Unresponsive or fully obstructed cases may require surgery, which can be very difficult and is not always successful. The key to prevention of sand accumulation is reducing sand intake. Know your soil type. If your horses live or eat around sandy soils, they are at risk for sand accumulation. In this case, it is not enough to simply feed in a hay bunk.  Horses eating hay from a bunk pitch much of it onto the ground and eat it from there. If that is happening, you may need to feed on mats or in feeders. Some horse owners construct special feeding areas to reduce sand ingestion. Horses thought to be ingesting some sand despite good management should be fed a psyllium product as directed.  Psyllium is a plant fiber that forms a watery gel in the intestine. It is thought to bind sand and act as a vehicle to move it out of the intestine. There are a variety of commercial psyllium products on the market.  Your vet can help you choose the most appropriate one for your situation. Just keep in mind that feeding a psyllium product is not a substitute for reducing sand intake through good management. Sand accumulation is a far-too-common problem that causes horses a great deal of pain and suffering. By being aware of and on the lookout for this condition, horse owners and caretakers have the opportunity to prevent it. Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Revised March 2013 
Subtle or Hard to Diagnose Equine Lameness: What Horse Owners Should Know Your performance horse (of any discipline) is not performing up to the level he has before.  Maybe he won’t take a lead, or won’t engage his hindquarters in quite the same way as he has in the past.  Maybe he won’t hold his sliding stop, or can’t perform a dressage movement that he usually performs consistently.  You notice that his back seems sore and tight after work.  Is it a training or behavioral issue?   Is there something subtle that might be causing him pain?  Is he just back sore?  You watch him trot around on a lunge line and you are not sure.  Maybe he seems a bit stiff, maybe not... This is a very common history for equine veterinarians to hear.  Very subtle lameness is often the reason for inability to perform.  The problems may be so subtle that they are missed by the rider and may barely be apparent to the veterinarian. In this article, I discuss what horse owners do, the process that veterinarians typically go through to diagnose lameness, and why sometimes we cannot make a diagnosis using that approach.  I then discuss more advanced diagnostic approaches useful in these cases. WHAT HORSE OWNER'S DO Subtle, hard to diagnose lameness are a common cause of poor performance by horses in all disciplines.  When faced with this problem, horse owners take one of many approaches: •  Some may not notice a problem and will keep working the horse, even though they wonder why he is not performing to standard.  Unfortunately, this is very common and often contributes to the problem. •  Some seek out alternative therapies or buy expensive supplements without taking the time to find out what the underlying problem is.  Without a diagnosis, this approach tends to be costly and ineffective and may also contribute to the problem. •  Some simply turn their horses out for extended periods of time believing that a bit of rest may solve the problem.  In many cases, this works.  However, frustration arises when the problem persists despite the rest.  At this point, horse owners need to consider contacting their veterinarian. •  Some call their veterinarian, who attempts to diagnose the problem so that it can be treated appropriately. THE VETERINARIAN'S APPROACH The lameness exam is a routine of veterinary procedures that narrows down the cause of lameness in a methodical way.  These exams are often satisfying for all involved and end in a definitive diagnosis of the problem causing lameness, allowing appropriate treatment.  In some cases there is swelling, heat, or obvious pain which causes the veterinarian to focus on an area of interest.  In other cases, there may not be visible injury but “blocks” (regional anesthesia of specific nerves, joints and other structures followed by reevaluation of the degree of lameness) can help narrow an area or structure as the source of the lameness. Following blocking, the next step is imaging of the bone and soft tissues (of the blocked area) using radiography (x-ray) and ultrasound, defining the nature of the injury.  Radiography generally provides an image of bone.  It is very useful for the bony components of an injury but does not give much information on other tissues. Ultrasound is excellent for visualizing the structure of muscles, ligaments, tendons and other soft tissues.  Once we have imaged the affected area, we usually have characterized the problem.  We are then ready to discuss available treatment options and prognosis. Unfortunately, however, this neat process of diagnosis and treatment is not always possible. The lameness exam may be able to rule out many causes, but there are cases in which we are not able to rule in a definitive cause for the lameness.  This situation is very frustrating for both the horse owner and veterinarian.  The most common area in which this occurs is in the upper hind limb and back.  In these places there is so much muscle mass that it is almost impossible to examine and image the structures. Failure to make a definitive diagnosis can happen in a number of ways.  The lameness can be so subtle or hard to characterize that the veterinarian does not feel that he or she can meaningfully interpret the results of blocks.   All possible blocks are performed, but the horse remains lame.   Blocks localize the lameness to an area but our methods of imaging do not show a significant problem.  This is common in the foot because of all of the soft tissue structures in the foot and the limited imaging capabilities of radiography. ADVANCED VETERINARY DIAGNOSTICS In cases where a diagnosis cannot be made using the usual approach described above, horse owners now have the option to utilize several advanced veterinary diagnostics.  These diagnostics have become more available and useful in the past 10-15 years. MAGNETIC RESONANCE IMAGING: MRI is an advanced imaging method that gives a very detailed image of both bone and soft tissue. It has shown us a level of detail in the lower limb only that we had never been able to see.  MRI has changed the way we think of foot lameness.  It has defined a whole variety of injuries that we did not know existed.  MRI primarily only visualizes the lower limb. As in human MRI, the patient part being examined must be within the working parts of the machine.  This makes it impossible to examine the large body parts of horses.  Not all MRI machines are created equal, they vary in quality of image and how large a body part can be imaged.  MRI usually requires general anesthesia so that the patient is adequately still.   This diagnostic is expensive, costing $1500-$2500.00 per exam at this time. NUCLEAR SCINTIGRAPHY or BONE SCAN: This technique is especially useful in cases where a conventional lameness exam and blocking may have ruled out many areas of the limb but not defined the location of the problem.  This is a technology that allows a picture of the whole horse skeleton to be viewed at once.  It involves the injection of a radioactive isotope bound to a molecule that when injected quickly travels to normal but especially actively changing bone.  Once the isotope has been injected and time allowed for it to spread throughout the body, the horse is photographed with a radiation counter (a gamma camera).  The injured area within bone “lights up” on the gamma camera image.  This modality is excellent for hard to diagnose lameness.  It is especially helpful for skeletal problems high up on the limbs where other imaging modalities cannot be used. These units are rare because they are extremely expensive to purchase and operate.  There are strong restrictions on their use because of the use of the public health concerns of using radioactive compounds.  Because of these factors, nuclear scan tends to be expensive, usually $1000-$2000.00 per study. CT or CAT SCAN: X-ray Computed Tomography is an imaging method in which a large series of x-rays are taken of an area, from different angles and at different exposures.  Using powerful computer processing routines, these images are assembled into a detailed 3 dimensional image of both soft tissues and bone.  This diagnostic is also expensive, and the cost can begin at $1500.00. Alternative Approaches: Horse owners faced with difficult to solve performance problems often become frustrated and seek an answer on the Internet and from other sources.  Here they find advertisements for individuals and products with claims to be able to solve every kind of equine performance problem.  Horse owners should be very skeptical of all of these claims, and use their veterinarian as a guide to help choose an appropriate path.  If it sounds too good to be true, it generally is. Alternative medicine may be helpful in some cases of obscure hind limb and back problems.  In cases where a conventional Western approach fails to define the problem, I encourage my clients to pursue these options if they are otherwise inclined. In addition, alternative therapies can be used in combination with or a supplement to Western approaches.  I always recommend seeking a dedicated, professional practitioner (usually also an equine veterinarian) with advanced training in one or more of the alternative therapies.  This practitioner should use the information already gathered by the primary veterinarian to help them in formulating their own diagnosis of the problem and in their formulation of a treatment plan. CONCLUSION It is important for horse owners to recognize subtle lameness problems that might be causing poor performance, resistant behavior and secondary problems like back soreness.  Even if you don’t see a lameness, remember how subtle these problems can be, and encourage your veterinarian to do a thorough lameness evaluation.  Most of the time a diagnosis will be made and treatment options will be available.  If the results of this are questionable, it then becomes important to discuss referral to a center that can offer more specialized diagnostics.  If this is not an option for whatever reason, exploring alternative therapy referral or extended turnout/rest may also be an option. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
Thal Equine Client Handout: Castration Care TIMING & PREPARATION Castration is surgical removal of the testicles.  It is performed on colts to modify behavior and to prevent stallion-like body development.  Castration is usually performed before the age of 24 months.  Any colt older than 9 months of age should not be put on pasture with fillies and mares because they may mount and potentially impregnate them.  In our area, we like to castrate colts during the cooler months when there are fewer flies. In normal colts, the testicles have descended into the scrotum by the time of birth.  In some colts, called "high flankers” or “ridgelings" by horsemen, one testicle does not completely descend into the scrotum but remains in the inguinal canal.  With time, and in some cases, this high testicle may descend into the scrotum and be more accessible for removal.  Colts that retain a testicle in the abdomen are known as “cryptorchid,” meaning hidden testicle.  Removal of retained testicles, called a “cryptorchid castration,” is more complicated and should be performed in a surgical center by a veterinarian experience with performing this procedure. Before castration, the colt should be accustomed to handling and be halter trained, so it can be easily managed during and after surgery.  Tetanus immunization is necessary before or at the time of surgery.  Postoperative care is usually needed for at least 2 weeks after castration, so schedule the surgery for a time when you will have the time to monitor the horse after the procedure.  Ideally, you should be comfortable handling the young stallion before having him castrated.  In some cases, it can take weeks to months for stallion-like behavior to decrease after castration.  Monitoring at home and caring for the colt according to instructions is essential for a smooth, uncomplicated recovery.  The period after castration is also a good time to begin daily training of your young gelding. THE PROCEDURE In our practice, we usually perform what is known as a recumbent (down) castration under short acting general anesthesia.  The colt lies on his left side with a hind leg tied up for positioning and access to the scrotum.  We perform the procedure in the field or at the clinic, and usually outside.  Some veterinarians prefer to perform the procedure standing but I prefer doing the majority down for a variety of reasons.  We use sterile surgical instruments for this procedure. I start by examining the colt to be sure that both testicles are down and that he is well enough for the procedure.  At that point, I give an injection of anti-inflammatories and antibiotics.  I feel that this increases comfort after castration and reduces the incidence of infection. I then give a sedative and loop a large, soft cotton rope around the colt’s neck.  Five minutes later I give a general anesthetic and the colt is laid down onto his left side.  The rope is brought around the hind leg and hock and the leg is lifted out of the way.  The scrotum is surgically prepared.  A large incision is made over one testicle, the testicle is exposed and sterile emasculators are used to crush the large vessels of the spermatic cord, preventing hemorrhage. The other testicle is similarly removed.  A surprise to some horse owners is that the incisions are left wide open.  Not only do I make very large incisions, I stretch the incisions even wider to improve drainage and reduce the chance for infection.  For the same reason, I remove extra skin, fat and connective tissue.  It usually only takes me 5-7 minutes to perform the actual routine castration procedure. We monitor the colt as he recovers from the anesthetic, which usually takes about 15 minutes.  At that point, he rolls to his chest and usually gets up easily with little assistance.  He will be unsteady on his feet for another 5-20 minutes, but after that he can be trailered or moved to a stall.  I also remove wolf teeth at no charge as part of our castration.  I feel that this is a great time to get this procedure done easily and without pain. POTENTIAL COMPLICATIONS Castration is a routine surgical procedure, but complications happen, and so those involved must take it seriously. It is nearly impossible to predict if postoperative complications will occur.  The most common complications include: BLEEDING:  Excessive post-operative bleeding after castration is more common in horses that have a clotting abnormality or very large testicular blood vessels.  It can also occur if the vessels are not properly crushed.  When properly performed though, most horses bleed very little. For older breeding stallions and those with very large testicles, we may choose to ligate (tie off) the large blood vessels to insure no hemorrhage.  This may add a few minutes to the procedure. INGUINAL HERNIA: In some horses, the opening in the abdominal wall (inguinal canal) through which the testicles descend into the scrotum is larger or more flexible.  In these horses, the intestines and other abdominal tissue can pass through the inguinal opening and come out the incision (called herniation).  Although inguinal hernias are uncommon, they are a life threatening complication and must be dealt with immediately and properly. INFECTION:  As mentioned, the incisions are not sutured and are allowed to heal from the inside out.  If the incision closes prematurely, infection can be sealed inside.  Post-castration infection usually causes excessive swelling of the scrotal area and sheath and a depressed attitude and appetite.  Horses with infections will often have a fever over 102.5 degrees.  This complication is most often seen 2-7 days after castration but can occur anytime. PREGNANCY: A recently castrated gelding can still get a mare in foal for some time after castration because of sperm remaining in the conducting system of the urogenital tract.  Recently castrated geldings should be kept away from females for at least 30 days. AFTER-CARE It is vital that you monitor your recently castrated gelding. For the first 24 hours after castration, keep the horse confined and calm in up to a 20’x 20’ stall or corral.  During the first 6 hours after surgery, look in on the animal every few hours, as directed. Look for streaming of blood from the wound.  Some dripping is to be expected for the first few hours after castration, but call us immediately if blood streams from the wound.  Also call us if you observe colic signs or any dramatic increase in scrotal swelling or pink/red tissue protruding from the wound. Exercise is important to help reduce swelling and facilitate drainage. We recommend starting the exercise program 24 hours after the procedure.  The exercise program should consist of 15 minutes of controlled exercise, once or twice daily.  Lungeing or ponying at the trot is best.  The horse may initially seem stiff, but this stiffness usually resolves with more exercise. Apply fly spray around the flanks and hindquarters.  Spray from the side.  Do not spray directly up into the wounds.  Fly spray can be very irritating to open wounds. The wound will heal over 2-14 days.  It will contract down over a few days to a much smaller wound and then fill with a bed of red tissue.  During the first few days to a week, any drainage will subside. During days 2 through 5, the scrotum may swell up to 3 times its original size.  This is normal.  This postoperative swelling is reduced with exercise.  The scrotum is usually back to normal size after 5 days but a bit of swelling may persist at the lowest part of the sheath. Clear, red tinged fluid draining from the wound is normal for the first few days.  If the drainage becomes yellow or pus colored, you should call our office. Any other recommendations, as directed by me or your equine veterinarian. PLEASE CALL US IMMEDIATELY IF: You have any questions concerning the castration and healing of the wound. Call us if you feel anything seems abnormal. Your horse acts depressed, or won't eat following the procedure.  This is probably the most important thing to watch out for.  He should always maintain a good appetite and attitude. You observe excessive swelling of the scrotum or sheath. Your horse's temperature in the morning, before exercise is greater than 102 degrees F. You observe excessive bleeding or drainage from the scrotal incision.  Bleeding is usually only a potential problem the first 24 hours after the procedure. You observe any tissue hanging out of the scrotal incision. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Thal Equine Client Handout: Common Diagnostic Tests for Equine Abdominal Diseases The purpose of this client handout is to describe some of the actions that I take in trying to determine the cause and severity of your horse’s abdominal illness.  If you have questions about any of the exam components or diagnostics performed, please feel free to ask me. HISTORY I usually start with a detailed history of the problem and your prior management of the horse, including any recent changes.  Questions involve things like symptoms shown, duration of symptoms, prior symptoms, past preventative health care, feed and management, and whether or not other horses are affected.  These pieces of information and others are critical to my understanding of the disease process. PHYSICAL EXAM In the physical exam, I evaluate the horse’s general systemic health.  I look at all major body systems from the outside, including the neurologic system, musculoskeletal system, cardiovascular system, respiratory system, digestive system, and reproductive system, etc...  General condition, attitude, coat and weight are noted.  Parameters such as temperature, pulse, respiratory rate and character, mucous membrane color, oral exam findings and many others are considered.  The specific body systems involved in the disease process are thoroughly examined. COLIC EXAM I assess the gastrointestinal tract.  Degree and duration of pain is an important factor in determining the best treatment options. Response to pain relievers is part of this evaluation. PASSAGE OF NASOGASTRIC TUBE One of the first steps in dealing with a horse in abdominal pain is to pass a naso-gastric or stomach tube.  This long, flexible plastic tube is inserted through one of the nostrils, goes through the nasal passages, pharynx, and follows the esophagus into the stomach. In the average adult horse the distance from the nostril to the stomach is 4 to 5 feet.  Passing a stomach tube can be tricky, as the veterinarian must be sure that the tube does not end up in the lungs. If fluid is pumped into the lungs, it will likely be fatal to the horse. Never try this yourself! Some horses tolerate this procedure well, while others resent it and require a twitch.  Occasionally, a horse will be extremely difficult and will require sedation in order to safely pass a tube.  Rarely, a horse will experience a bloody nose following the procedure.  This results from abrasion to delicate membranes in the nasal passages by the tube and is usually a minor problem. Passage of a naso-gastric tube is done for several reasons: As a diagnostic tool to assess whether or not there is fluid accumulating in the stomach. In a normal horse, there is little fluid accumulation in the stomach.  If there is significant fluid accumulation, it can mean that there is a blockage of the upper part of the intestinal tract, which is causing backup of fluid into the stomach.  We call this abnormal accumulation of fluid “reflux."  Knowing whether or not there is reflux is important diagnostic information. To relieve overfilling of the stomach and intestine with reflux in cases where this is causing pain or contributing to the disease process. To administer fluids and other medications into the stomach, when appropriate. RECTAL EXAM A lubricated and gloved arm is placed in the horse’s rectum in order to feel the anatomy of the back half to two-thirds of the abdomen.  The rectum is thin walled and with careful examination and lots of experience, an equine veterinarian can feel and evaluate many of the abdominal organs through it.  Structures such as the left kidney, the large colon and other parts of the intestine, the inguinal rings, the bladder and parts of the reproductive system can be evaluated.  A specific problem with the intestine or other organ is sometimes diagnosed. More often, I am able to determine what is going on by feeling gas or fluid distension patterns or a specific segment of intestine in the wrong position in the abdomen.  Sometimes the rectal exam findings are completely normal, and this in itself is very helpful information.  I may sedate or twitch your horse for this procedure for better relaxation of the horse and rectum.  A very rare complication of rectal examination is tearing of the delicate rectal wall.  While this is a very uncommon complication, it can be fatal.  It is important that you understand that there is a small risk associated with the procedure. ABDOMINAL ULTRASOUND In some cases, I may choose to use ultrasound of the abdomen as an additional diagnostic tool.  Abdominal ultrasound may be used either trans-rectally (through the rectum) or through the abdominal wall from the skin.  The ultrasound emits sound waves, which pass through tissue at various speeds depending on specific tissue characteristics.  The sound waves bounce back to the transducer and a picture is produced by computer analysis of the returning sound waves.  Ultrasound can give additional valuable information regarding the position and state of various parts of the intestine. It is also used for evaluation of the tissue characteristics of liver, spleen and other abdominal organs. BLOOD WORK/TESTS A complete blood count (CBC) includes a count of red blood cells and several populations of white blood cells.  A complete blood count gives me valuable information about the health of the horse, its hydration status and characteristics of the disease process.  A white blood cell count is especially helpful in supporting a diagnosis of bacterial infection.  I usually perform the complete blood count in our hospital. The serum chemistry is a battery of individual blood tests for levels of about 15 enzymes and molecules within the blood.  Serum enzyme level increases can indicate damage to specific organs. An example of one of these enzymes is LDH (lactate dehydrogenase).  This enzyme is found only in liver and muscle cells.  Large elevations in this enzyme can mean that either liver or muscle cells have been damaged and their enzymes released into the blood.  I use the rest of the exam and other blood work findings to interpret the significance of individual tests like this.  Examples of other levels measured are glucose (blood sugar), creatinine (an indicator of kidney function), and many others. I-STAT TESTING The I-STAT test is a complement to serum chemistry, which allows us to measure a group of other critical blood parameters like blood oxygen, carbon dioxide, electrolytes and others.  In certain cases, the ability to measure these quickly and accurately in our hospital can be the difference between life and death of a very sick horse. Serum chemistry and I-Stat tests are performed using sophisticated and expensive equipment in our laboratory.  We have chosen to purchase this equipment so that we may offer you the very best care for your horse.  Having this capability gives us the ability to make decisions quickly, rather than having to send samples away and wait for days for a result.  Sometimes we do choose to send blood away to a reference laboratory to have the testing done there.  This is usually because the lab may offer other specific tests which we cannot perform in our hospital, or there is less urgency in a specific case and so a longer turnaround time is acceptable. ABDOMINOCENTESIS  a/k/a BELLY TAP An important and common diagnostic test used in cases of abdominal illness in horses is abdominocentesis or belly tap. This involves collection of a sample of fluid from the abdominal cavity.  This fluid bathes the outside of the intestine and abdominal organs.  Changes in this fluid, both visible and laboratory results, give critical information regarding the health of these organs. Certain changes suggest presence of or severity of damage to intestine and so can help determine the need for colic surgery or intensive care. The procedure involves clipping a specific site on the lower belly.  This site is then carefully disinfected.  A needle is introduced carefully into the abdomen, using special care not to puncture intestine or other organs. The needle is maneuvered until fluid is encountered, and a small sample of this is caught in 2 types of tubes.  In our hospital, we are successful at obtaining fluid in about 70% of cases by using this technique.  In cases in which we are unsuccessful, we resort to using a larger tube and different, more complicated procedure.  Occasionally, we are forced to use the ultrasound to help us locate small pockets of fluid within the abdomen.  Unfortunately, there are cases in which it is just not possible to collect abdominal fluid.  This is usually because there is very little fluid in the abdomen.  In other cases, clots of inflammatory material can block the needle or tube. Once a sample is collected, it is analyzed in our lab for certain cell and fluid parameters.  Total protein is commonly measured. Total protein is very low in normal abdominal fluid.  As intestine is damaged, the intestinal vessels become leaky and allow protein to escape from blood and enter the fluid.  We then see an increase in total protein in the fluid, which is useful in determining progression of the disease.  Properly done, the risk of abdominocentesis is minimal.  However, this risk is somewhat greater in foals. As I gather all of the information from the diagnostics above, I begin to determine what is wrong with your horse, and begin to develop a treatment protocol.  In exigent circumstances, I work quickly to gather this information and present it to you for discussion.  If you have any questions, please do not hesitate to ask.  Sometimes it can be a confusing and complex process and I want to ensure that you fully understand what is going on with your horse and the treatment options so that you can make the right choice for your horse. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Thal Equine Client Handout: Equine Behavioral Workshop Some Take Home Points from our October 15, 2011 Equine Behavioral Workshop I owe the late and great Ray Hunt a debt of gratitude for first opening my eyes to a new way of seeing horses. It’s never the horse’s fault. Always look inward to find the reason (variation on RH). Be suspicious of anyone who tells you there is only one method or device needed for getting something done. You will form your own methods. Recognize all time with your horse as relationship time and all interactions as important. Your time with your horse doesn’t start and end when you might think. You will immediately establish a relationship. Make it one in which you are the leader. Set your horse and yourself up for safety and success (a variation on RH). Identify what you know about the horse (hear-say, past experience, etc.) then drop pre-conceived notions (labels) and be present with the horse. Show a boundary and show an open door. This is how you develop trust and respect. RH said “Make the right thing easy and the wrong thing hard." Manage your own fear and confusion. If you do get confused (and we all do) STOP. Manage it. Breathe. Break tasks into smallest components or steps. Achieve those individually, sequentially, and meticulously, and your task will be complete. Follow the "2 Minute - 30 Second Rule" i.e., if you aren’t able to describe the progress you are making, STOP, think, change. Have multiple tools in the toolbox. Use meticulous timing with pressure and release to achieve lightness and build trust. Use gradients of intensity in interaction, starting with the lightest. Maintain ongoing trust, progress and consistency by asking the right things and succeeding. Observe and respect the equine cost/benefit equation that horses live by (i.e. security). End every micro-interaction on a high note. See even the seemingly difficult as just one more opportunity to teach your horse. Seek those experiences rather than shunning them. Your time constraints mean nothing to horses. The horse is the ultimate arbiter. All of our notions ultimately don’t matter. Is the horse improving? Is the horse achieving what we are asking? That tells you how you are doing. Recognize that we all have blind spots. Always seek to improve and grow. See this not so much as a goal, but as a lifelong path. Have fun.  Developing a good relationship with horses is a life-long endeavor that I have always greatly enjoyed - as a horse owner and as an equine veterinarian.  Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated September 2011 
Thal Equine Client Handout: Giving Your Horse Oral Medications The most important part of any oral treatment is seeing that your horse or foal gets the total dose of medicine at the prescribed time for the total number of days, as directed by your equine veterinarian.  As discussed in greater detail in my article "How to Perform Veterinary Treatments on Your Horse Without Drama," envision this task within the context of your relationship with your horse.  It is simply another opportunity to train your horse to do something that you ask of it.  Likewise, it is good to practice this skill before it is necessary. TABLETS There are two ways to give tablet medication, mixing the tablets with feed or giving it by oral dosing, usually in a modified syringe.  The method you select depends on a number of factors, including the likelihood of your horse refusing the medication in the feed, and how effectively he or she can be orally-dosed. ORAL DOSING OR PASTING Oral dosing is similar to paste worming.  The best technique we have found for difficult horses is to first try to get a single finger in the corner of the mouth.  If your horse resents this, practice it until he accepts it.  If he accepts it, slide it in a little way and back, to stimulate his tongue.  He will usually open his mouth.  Be careful to keep your finger from going back far from the corner of his mouth. You can be bitten severely by the large molars that are further back!  I would be happy to show you this technique in person. Once the horse relaxes and opens his mouth, gently slide the syringe with medication as far back as possible, while trying to avoid upsetting the horse.  Push the plunger when the syringe tip is about at the base of his tongue.  For horses that tend to spit out medication, slide the syringe or your finger gently back and forth to stimulate tongue movement.  This will tend to stick the medication to the tongue and prevent the horse from spitting it out.  Holding the muzzle up after dosing will also discourage spitting out. Depending upon the medication, some tablets will easily dissolve in water, so just add pills to syringe, then water to fill syringe and shake it a bit.  Some tablets will not dissolve in water, so you must crush them first.  Ask your veterinarian for specifics.  He or she may also suggest that you also add molasses or Caro syrup to improve taste.  Some horses resent oral medication, but most tolerate it well.  Watch to see if your horse swallows the medication or if it comes back out of the mouth. MIXING WITH FEED Some tablets can be mixed with feed, supplements or grain.  Some tablets are so small that they can be mixed with the feed without crushing, while others need to be crushed.  Larger tablets or boluses can be crushed with a mortar and pestle, or a hammer can be used to crush the tablets wrapped in a small plastic bag.  A coffee grinder works well for crushing pills quickly and easily.  Mix the powdered tablets into the horse's feed, as prescribed. POWDERS & GRANULES Powders or granules should be mixed directly with the feed.  Dampening the feed with molasses makes the mixture more palatable for your horse and keeps powders, granules and small tablets from separating out. Check the bottom of the feed bucket 15-30 minutes after feeding to make sure the entire mixture has been eaten. Call me if you have any questions or you are having difficulty giving your horse oral medication. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
Thal Equine Client Handout: Intramuscular ("IM") Injections This handout is intended for clients that are comfortable and willing to administer intramuscular injections and have horses that are relatively well-behaved during this process.  It is only recommended when the client is fully advised by their veterinarian or has communicated with their veterinarian about the situation calling for such an injection.  If you are unsure or your horse is needle-shy, you need to consult with me or another equine veterinarian to develop an appropriate plan. Administering any type of medication to a horse by any route requires thought and attention.  Intramuscular  (“IM”) injections are no exception.  IM injections are very safe if done properly but if done improperly they can lead to serious complications.  Below are some suggestions for giving a safe IM injection.  Sterility is paramount in handling a needle, syringe, the bottle containing the medication, and the injection site. PREPARATION Use a new sterile needle each time.  Handle the needle by the hub only and don't touch the needle shaft.  Keep it capped until ready to inject.  Wipe off the rubber top of the medication bottle with an alcohol swab. Attach the covered needle to the syringe, remove the needle cap and fill the syringe with air.  Then insert the needle into the bottle.  While tilting the bottle upside down, inject air into it to produce some back pressure, then slowly withdraw the solution into the syringe.  Fill the syringe with a few more cc's than required.  Then inject that small extra amount back into the bottle with any obvious air.  This is all accomplished with the initial single needle stick into the inverted bottle.  Withdraw the needle from the bottle. Hold the syringe with the needle pointed upward, tapping your finger along the barrel of the syringe.  This moves any bubbles to the neck (needle end) of the syringe so you can push the plunger up a bit to force out any remaining air.  Now you have only the prescribed amount of injectable medication in the syringe.  Recap the needle. GIVING AN INJECTION Have the horse stand in a location where it would not hurt itself or you or damage equipment if a problem should arise.  Have another person hold the horse with a sturdy halter and rope.  The horse should be held and observed for 2 minutes after the injection for any signs of an unfavorable reaction. Select an injection site, see diagram below. The neck is a commonly used site and works well when giving only a few injections.  When giving a series of injections over several days or weeks, alternate among the 4 locations - 2 sites on each side of the horse.  Alternating locations helps to reduce local reactions and soreness. Brush off any dirt and debris from the injection site and swab the skin with an alcohol-soaked cotton ball.  If giving the injection in the neck, we recommend leaving the needle attached to the syringe.  Pinch the skin tightly near where you plan to give the injection.  Let the horse adjust to this for a few seconds.  While continuing to pinch with one hand, gently but firmly push the needle into the neck in the desired site at right angles to the skin and to depth of the needle hub. When injecting sites other than the neck, first detach the needle from the syringe and remove the needle cover.  Just before you insert the needle firmly tap the area near the insertion site with your finger so to reduce the chance that the horse will react to needle insertion.  Gripping the needle hub (do not touch the shaft), quickly plunge the needle into the muscle up to the hub.  Remember, rapid needle insertion is less painful than slow insertion.  If blood appears at the needle hub, withdraw the needle and reinsert it at a different location.  Re-attach the syringe to the needle and gently withdraw the plunger a short distance.  If any blood is withdrawn into the syringe, the tip of the needle is probably in a vessel.  If this happens, partially withdraw the needle and angle it slightly before reinserting it.  You need not remove the needle completely from the skin when redirecting it.  Again gently withdraw the syringe plunger to check for blood. If there is no blood at the needle hub, inject the medication very slowly.  When injecting more than 10 cc, it is preferable to spread the medication into a few injection sites.  To do this, inject the first 10 cc.  Rather than removing the needle completely from the skin, partially withdraw and redirect the needle and give another 10 cc. Remember to "pull before you push" at each site to avoid putting medication into a vessel. Repeat this in different directions until all the medication has been given. Try to avoid injecting air into the horse.  If for some reason you inject a small amount of air, it will not be of serious consequence, but is best to avoid injecting large amounts. Quickly withdraw the needle.  Recap the used needle and properly dispose of it.  You should return the used needles to us for proper disposal. ADVERSE DRUG REACTIONS If, as you are giving the injection, the horse stiffens its neck, becomes very alert in the eyes, flicks its ears, moves around, and increases its rate of breathing, immediately stop the injection.  This rare adverse reaction can progress to more agitated behavior, such as jumping forward, circling, stumbling and sometimes collapse.  Such reactions can last 1 to 10 minutes.  There is no treatment except to try to prevent the horse from injuring you, your assistant, or itself.  Most horses survive this unusual reaction.  Such a reaction may be a result of accidental injection into a vessel or an allergic reaction.  It is most commonly seen with penicillin injections. LOCAL SWELLING When giving a series of injections, alternating injection sites helps reduce post injection swelling.  If the horse develops swelling in an injection area, apply a hot pack to the site for 15 minutes twice daily.  Never use a swollen site for another injection.  If the site continues to increase in size and pain persists 1-2 days after the injection, please call our office immediately. Call us if you have any questions concerning the intramuscular injection procedure or if your horse has any adverse reaction to the drug or the injection. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
The Equine Eye: What Horse Owners Should Know The equine eye is a miraculous and delicate organ.  Veterinary problems relating to the horse’s eye are common, and should be recognized and treated appropriately.  There are many types of problems that affect the eye, but the purpose of this article is to touch on a few of the most common.  Injuries and disease involving the eye are usually considered veterinary emergencies.  Disease processes in the eye can progress rapidly, and can quickly lead to permanent loss of vision.  The cost of making a mistake is great.  Once the eye is severely damaged, restoration to a functional eye may be impossible.  The goal of this article is to discuss the basic structure and function of the equine eye, the common veterinary problems that affect the eye, diagnosis, and treatment. THE EQUINE EYE [caption id="attachment_6946" align="alignleft" width="384"] Equine Eye - Basic Anatomy[/caption] The eye is a fluid filled globe that sits in a protective bony socket within the skull.  It can be thought of as virtually an extension of the brain.  It is closely associated with the brain both in location and nerve connection.  The surface of the clear part of the eye is known as the cornea.  Just inside that is the anterior chamber, filled with thick clear fluid known as aqueous humor.  The colored part of the eye is the iris.  It is a thin ring of two layers of muscle that contract and relax to either open or close the pupil.  The size of the pupil determines the amount of light allowed into the back part (image forming part) of the eye. The pupil contracts under bright light conditions and enlarges in low light.  Just behind the pupil is the clear lens, which focuses an image on the back wall of the globe.  The projection screen of the eye is called the retina.  The posterior chamber is the back chamber of the eye and is also filled with a clear jelly-like substance.  The retina makes up the back wall of the posterior chamber and is made up of millions of light and color-sensing cells.  The projection of an image onto the retinal surface stimulates the retina cells, which translate their stimulation into nerve impulses.  This is communicated through the optic nerve to the brain, which produce an image.  The eyelids have tear glands that produce tears, keeping the eye moist.  A duct known as the nasolacrimal duct drains the tears to a small opening just inside the nostril.  Blockage of this duct causes a runny eye. The horse’s eye has some unique features.  It is very large and well adapted to the life of a prey species living in wide-open country.  Horses have excellent peripheral vision.  The third eyelid is a pink membrane which moves over the eye from the inside corner toward the outside corner.  Its function along with the upper and lower lids is to protect the eye from trauma.  An unusual feature of the equine eye is a structure known as the corpora nigra.  This knobby structure juts out from the top of the iris and functions to shade the pupil from glare, just as the bill of a baseball cap shades our eyes.  Horse owners are sometimes curious about this strange structure and call our office concerned that it is a problem. [caption id="attachment_6947" align="alignright" width="300"] Equine Eyelid Wound[/caption] EQUINE EYE PROBLEMS Because of their speed and tendency to move their heads violently, horses are predisposed to eye injuries.  Wounds often involve the eyelids and sometimes damage the eye itself.  Wounds that are near the eye or involve the eyelids should be seen by a veterinarian immediately.  Careful surgical repair of eyelid wounds is critical.  Failure to repair these injuries correctly can lead to an eyelid that does not function correctly, or actually irritates and damages the eye. [caption id="attachment_4516" align="alignleft" width="300"] Penetrating Wound to Eye/Eyelid[/caption] Corneal ulcers and injury are very common.  Corneal ulcers may be caused by trauma, fly irritation or foreign bodies (plant awns, burdock) that get into the eye.  This irritation can cause a small break in the thin outer membrane of the cornea.  Once a break occurs in this thin corneal surface layer of cells, bacteria can colonize and break down the corneal material, expanding the ulcer.  It is very important to treat corneal ulcers quickly and appropriately.  Many horses lose their sight as a result of owners failing to treat this problem.  Corneal ulcers can be difficult to see.  Horses often just appear to have a weepy eye.  On closer examination, a gray discoloration of the cornea can sometimes be seen.  Veterinarians usually use a fluorescent dye (fluorescein) to stain the surface of the eye to make the ulcers more visible.  This stain usually makes visible even tiny breaks in the surface of the cornea.  This is important because the approach to treatment is different depending on whether or not there is a break in the cornea. Another common equine eye problem is Equine Recurrent Uveitis (ERU), also known Moon Blindness or Night Blindness, and Anterior Uveitis.  This is an inflammatory condition of the front chamber of the eye including the iris and sometimes the cornea.  This chronic inflammatory disease is the most common cause of blindness in horses.  It is usually treatable but requires long-term management. Cataract occurs in horses and can cause partial or complete blindness.  Cataract is an opacity of the lens.  It can occur for a variety of reasons.  Trauma or injury to the eye is the most common cause of cataract.  Congenital cataracts are fairly common as well, especially in some breeds.  Mild cataract is common in very old horses. At our high altitude, squamous cell carcinoma (a type of skin cancer) is a very common disease of the eye.  It is caused by the effects of ultraviolet light on non-pigmented tissues.  It is thus especially common in paint horses and Appaloosas, or any horse with no pigment in the skin around their eye.  These tumors can be on the cornea itself, and appear as a pink to gray discoloration of that otherwise clear tissue.  Or they can also look like inflamed tissue or a pink growth on the skin of the lids, the white of the eyeball, or the third eyelid.  Prompt treatment is necessary because these tumors can spread to the deeper tissues behind the eye, where they are difficult or impossible to treat.  Horse owner should realize how common this problem is at high altitudes in these horses.  I consider any reddish tissue in horses with pink skin around their eyes as cancerous until proven otherwise.  There are also other less common tumors that involve the eye and the surrounding tissue. The most common eye problem in foals is known as entropion.  In entropion, the eyelids are rolled inward, causing the eyelashes to be in contact with the cornea.  This can cause severe irritation and damage.  There are simple veterinary treatments for this and breeders should be on the lookout for it.  It generally appears in a young foal as a runny, irritated eye.  Foals can have other congenital problems of the eye.  A post-foaling exam by your veterinarian usually detects these problems. Certain equine breeds are predisposed to eye problems.  The Appaloosa breed is predisposed to ERU.  Morgan Horses are predisposed to congenital cataract.  Paint Horses, Appaloosas and other horses with pink skin around their eyes are more prone to squamous cell carcinoma.  Other breeds have predispositions to other problems. DIAGNOSIS & TREATMENT Examining and treating the equine eye can be difficult, especially when it is painful.  It takes good horsemanship and technique to do it safely and effectively.  Your horse should be comfortable with you handling his eyelids and covering his eye so that if you ever are forced to treat the eye, you can do it easily and without drama. Veterinarians methodically examine the eye both with and without an ophthalmoscope.  Other instruments are less commonly used.  We sometimes paralyze the lids so that they can be held open easily, or anesthetize the surface of the eye with special topical local anesthetics.  As is done in human eye exams, at times we dilate the pupil with topical medication.  The treatment chosen depends totally on the diagnosis.  Often ointments or drops are prescribed. As I discuss in many of my articles, you should have a trusted veterinarian with whom you can discuss any equine health care question.  This is very important with respect to disease and injury of the eye.  Call your veterinarian early on when you suspect injury around or involving the eye.  From your description, he or she may choose to have you treat it, or may feel that it needs to be seen.  Prompt and appropriate treatment of eye problems usually results in positive outcomes.  Delay in diagnosis and treatment can cost a horse its vision. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011    Would you like to learn more about the equine eye on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:        Observation - Eye Looks Cloudy or Gray, All or Part       Observation - Eyelid is Wounded or Cut       Diagnostic - Opthalmic or Eye Exam       Diagnosis - Corneal Ulcer, Scratch or Abrasion       Skill - Assess Eye       
The Equine Hock: What Horse Owners Should Know The "hock" is a horseman’s term for the tarsus, an anatomic region of the horse’s hind limb.  Horses of all breeds, types, and disciplines can suffer from hock-related lameness problems, especially those that work heavily off of their hind limbs.  This article discusses basic hock anatomy and function, describes desirable hock conformation, and discusses common lameness problems associated with this area. WHAT IS THE HOCK? [caption id="attachment_6958" align="alignright" width="314"] Equine Hind Limb[/caption] A horse’s hock is the evolutionary equivalent to the human ankle.  When looking at a horse from the side, the point of the hock is the backward-pointed part halfway down the rear limb.  Over millions of years of evolution, the ankle and part of the foot of the early horse raised off the ground, leaving the horse walking on the tip of its third toe.  This evolved into the hoof.  The other toes and several of the metatarsals (foot bones) were lost in the process.  This lower limb change was part of the adaptation that allowed the horse’s lower limb to become lighter and better adapted for explosive speed.  Horses were heavily selected for great speed as they occupied the prehistoric plains.  At that time, there was a great assortment of effective predators that culled any individuals that were slow. The hock is complex, and consists of four basic joints and many bones, all joined by ligaments.  The topmost joint is the high motion joint and accounts for about 90% of the range of motion in the area.  The three lower joints together account for the remaining 10% of range of motion and consist of two rows of cube shaped bones lying on top of one another.  Below the lower row of these small bones is the cannon bone, which drops down to the fetlock.  The digital flexor tendons pass through and over the inside and back part of the hock, and are critical to supporting the horse’s weight.  The Achilles (gastrocnemius) tendon runs down the back of the limb above the hock and attaches on the point of the hock.  If this tendon is cut, the whole function of the hock is lost, the hocks folds, and a horse cannot support any weight. CONFORMATION Ideal hock conformation varies depending on the breed and intended use of a horse, but there are some basics that every horse owner should know about conformation in this area: A hock should appear stout and smooth, without obvious swellings.  The left and right hocks should look symmetrical.  The bones that make up the hock should generally be thick and heavy.  This is simple mechanics; there are massive stresses placed on the lower limb of working horses.  If this structure is too light, there is a greater chance for injury. When looking at the hock from behind, the limb should appear straight through the hock, without major angulation inward or outward. When looking from the side at a horse that is standing squarely, the cannon bone should be near perpendicular to the ground.  The angle between the limb above the hock and below the hock should not be too straight (post legged) or too angled (sickle hocked). Deviation from good hock conformation just means that there will be more stresses placed on the joints, tendons, and ligaments.   This may increase the chance for hock-related lameness. Major changes in hock conformation and rear limb conformation can limit performance in certain disciplines.   An example is found in cutting and reining horses, which are expected to stop and turn hard on their hind limbs.   Hocks that are placed too "high" (i.e. long cannon bones) create a mechanical disadvantage for this kind of work and are considered undesirable for this discipline. [caption id="attachment_6965" align="alignleft" width="307"] Equine Lower Hind Limb[/caption] COMMON HOCK-RELATED LAMENESS Lameness problems that commonly arise in the hock area have, through hundreds of years of observation by horsemen, been coined with various names including "bog spavin," "thoroughpin," and "capped hock."  These terms refer to swellings in various structures of the hock. The most common problem associated with the hock is arthritis and pain in the lower, low-motion joints of the hock.  Swellings and obvious lameness related to these joints has historically been known by horsemen as "bone spavin."  Even though these lower joints account for little range of motion, they are commonly the cause of hock-related lameness, especially in horses competing in disciplines that require more use of the hindquarters.  Deviations from normal hock conformation mean a higher likelihood of development of problems in this area. Many performance horses are routinely treated for pain in these lower hock joints. Injection of the joints with a steroid with or without other anti-inflammatory medication is a very common procedure in the performance horse world.  While joint supplements like glucosamine, chondroitin sulfate, and MSM may help overall joint health, they often do not drastically improve lameness from hock arthritis. The good news is that this problem can usually be managed to allow horses to continue to work.  For horses that do not respond to typical treatments and management, these low motion joints may be surgically fused, which, in many horses alleviates the lameness.  Relatively new, and potentially very effective therapies that we now use to treat pain in these joints include shockwave treatment, and injection of the low motion joints with alcohol to chemically fuse them. A common lameness in performance horses, which can be confused with bone spavin, is injury to the high suspensory ligament at the back of the hock.  This important ligament can be a source of low-grade chronic pain and can be difficult to diagnose and treat.  Another common lameness in this region is osteochondrosis (OCD), a problem of abnormal joint development.  OCD can be found in any joint but the top (high motion) joint of the hock is a common site.  The problem usually appears as lameness or swelling of this joint in young horses. Back soreness is often secondary to hock and other hind limb lameness.  Underlying lameness should always be considered and ruled out in a back sore horse.  It is unfortunate when horses are treated for a sore back for long periods of time, often with alternative therapies, without considering that a lameness-related problem is the source of the back soreness.  A more effective approach is to work with your veterinarian to diagnose specific lameness problems first, and then to treat and manage these problems appropriately.  Back soreness often improves when the lameness is alleviated.  That said, there are some back problems that are not related to underlying lameness. THE LAMENESS EXAM The lameness exam is a methodical process of elimination your equine veterinarian conducts to arrive at a diagnosis.  This exam begins with a careful history and physical examination.  In any lameness exam, it is important to know the type and amount of work the horse does.  In the exam, there may be obvious swelling or symptoms of a problem in the painful area, but more often there is not. A common procedure done in assessing hock lameness and hind limb lameness generally is the "Spavin" test (hock/stifle or upper limb flexion).  In doing this, the examiner holds the hock and upper limb in flexion for a given period of time and then evaluates the change in degree of lameness when the horse is asked to trot off.  While flexion of the upper limb often makes hock lameness worse, it also will accentuate lameness from other parts of the limb, and so must be thought of as just one piece of useful information and not a diagnosis in and of itself. In all lameness exams, the lameness is first narrowed down to an area using examination, flexion, nerve and joint blocks.  Once the lameness is narrowed down to a region, then x-ray, ultrasound and other imaging techniques are used to define the problem precisely.  Proper treatment always depends on making a correct diagnosis.  As I mentioned before, a very common treatment is hock injections performed on the lower hock joints.  Treatment of OCD might involve surgery or joint injection.  Treatment of suspensory ligament injuries usually requires ample healing time but can also being treated effectively with newer therapies like extra-corporeal shockwave application and injection of stem cells into the injured area. PREVENTION OF HOCK PROBLEMS The first step in preventing hock problems is to select horses that are the appropriate type and conformation for your intended use, and do not have preexisting lameness problems.  The most reliable way to do this is to have a pre-purchase examination performed by a qualified veterinarian.  Hock conformation is a very important part of a pre-purchase examination.  Breeders should select for horses with good hock and rear limb conformation. As a horse owner, you should be familiar with the basic anatomy of the hock and what your horse’s hocks look like normally.  This enables you to recognize swellings and other abnormalities that might suggest a problem.  Be aware of your horse’s normal behavior and movement.  If you suspect that your horse is lame or back sore, consult your veterinarian early for a proper diagnosis and treatment.  It is also very important to follow a program for conditioning performance horses to prevent overloading and injury of tendons and ligaments in this and other areas. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   Would you like to learn more about the equine hock or tarsus on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:        Observation - Swollen Hock, Generally       Observation - Excessive Bend in Hocks, Sickle Hocks       Diagnostic - Radiography, Hocks or Tarsus       Diagnosis - Bed Sores, Fetlocks or Hocks       Diagnosis - Bone Spavin, Distal Hock Arthrosis       Diagnosis - Osteochondrosis, Osteochondritis Dissecans, OCD       
The Importance of Pre-Purchase Exams For horse people, the purchase of a new horse is an exciting time.  Unfortunately, many horses are purchased that are not suitable for their intended use.  This lack of suitability is most often due to a lameness problem that was not noticed at purchase, but can result from anything from behavioral to general health issues. As an equine veterinarian, I often run into the scenario when a horse has already been purchased and then found to have a problem.  It is a great disappointment for a new horse owner to learn that they have just bought a horse with a handicap that will make it difficult or impossible for the horse to perform its intended use or at its intended level, and that it may now be impossible to return the horse to the seller or sell it. The goal of this article is to explain the goals, components and limitations of the pre-purchase exam and to encourage readers to have it performed before they buy a horse.  Even when the purchase price is low, the cost of horse ownership is always very high.  I believe that if you buy a horse, it should be one that is sound and in line with your needs.  In the horse business it is buyer beware!  A pre-purchase exam is a very smart investment in peace of mind. COMPONENTS & GOALS A pre-purchase examination is a thorough veterinary exam performed on a horse before a buyer agrees to purchase it.  After deciding on the specifics of what the exam will entail, the buyer pays a veterinarian for his or her objective evaluation of the horse, taking into account a balance of factors.  After the exam, the veterinarian usually provides a written report to the buyer detailing their exam findings and recommendations.  The goal is an educated buyer, who will be satisfied should they proceed with the purchase given their specific requirements. Clear and honest communication between the buyer, seller and veterinarian, before the exam is conducted is extremely important.  Examples of this include: A clarification of the buyer’s expectations and goals for the horse.  This means a discussion of the buyer’s experience level and intensity of intended use for the horse.  I generally ask the buyer if they have any special reservations or concerns about the horse at this time. The buyer’s expectations of the exam.  Pre-purchase exams can be very basic or can employ all sorts of diagnostic tests, depending on the buyer’s budget and their willingness to assume risk.   The exam is often radically different for a horse purchased as a trail horse for an inexperienced rider than for one purchased as a high level dressage or Western performance horse. A discussion with the seller.  Information I like to get from the seller includes the work history and prior performance level of the horse, and especially the horse’s recent work schedule and intensity of that work.  I also ask questions about general care and management, any special care given and any health problems the horse might have had, including prior lameness and colic. THE EXAM I offer a standard, core pre-purchase exam.  The price for this exam does not include any diagnostic tests.  These are added at the end of the exam as needed and depending on intended use, the buyer’s expectations and risk aversion, and my findings in the initial exam. I perform an initial quick assessment of the horse’s basic health at rest, which includes inspecting it to confirm that its age and general description match to the buyer’s understanding.  I then follow with a brief, initial lameness exam.  If the horse is found to be sick, unsuitable, or lame in this early part of the exam, then the exam is stopped and the buyer pays a minimum fee.  The rest of the examination is canceled or delayed. Lameness is the most common and significant problem encountered in a purchase exam.  Thus the lameness part is very detailed and makes up the bulk of the exam.  I start by carefully examining the musculoskeletal system.  I then watch the horse move through a variety of patterns both in hand and loose in a round pen and on different footings.  Next, I perform flexion exams and hoof tester application.  If I find that the horse is lame, I stop the exam. If my general sense is that the lameness is not chronic or severe, I might advise the buyer that they shift the burden onto the seller and his veterinarian to diagnose and treat the lameness for a period of time.  The seller must satisfy me that the problem is not serious and poses no threat to the goals of the buyer, and the horse must undergo a full recovery before the exam is rescheduled.  If, on the other hand, the lameness appears to likely be of a more chronic or debilitating nature I generally advise my client that they search for another horse. If the horse is sound from a lameness standpoint, then examination of all of the other body systems is completed.  If all of this is done, and the horse is sound and healthy, then I discuss other tests that might provide additional information and even greater security in the decision to purchase.  Additional tests are done depending on the buyer’s needs and budget, and my recommendations for that particular case. Additional tests include radiography (x-ray), ultrasound, reproductive tests, blood tests, and drug testing.  For performance horses, a series of radiographs on the front feet and hocks might be advised.  For a broodmare, reproductive ultrasound and other reproductive tests may be appropriate.  Sometimes, we perform drug screens to ensure that the horse is not medicated during the exam. Some veterinarians include radiographs, as a part of every purchase exam.  There are advantages to this approach.  Even if a horse is not lame, the horse may have an abnormality that would not have been found otherwise.  This problem may raise concerns about the soundness of the horse.  Radiographs and other diagnostics done at the time of purchase also serve as a baseline so that progression of a problem can be assessed. However, sometimes diagnostic tests complicate what was a clear picture.  An example of this is when a sound horse is found to have a subtle problem visible only on radiographs.  For each specific finding, there is a different risk that the problem will interfere with the intended use of the horse.  This is where the whole process becomes as much of an art as a science.  The significance assigned to a given problem depends on the veterinarian’s experience and knowledge of the problem and the typical outcome he or she has experienced for this problem, in a horse of this type, engaged in this activity, at this level. I do not “pass” or “fail” a horse in a pre-purchase exam.  It is always the buyer’s decision whether or not to proceed with the purchase.  My job is to objectively provide the buyer with all of the information needed to help him or her make an informed decision. PITFALLS & LIMITATIONS Accurate prediction of the future is impossible. Often, the buyer and seller are not present for the exam so communication among parties is difficult and can be strained. It is risky to examine a horse that has not been in work.  Lameness problems may not be visible during the exam but can show up when the horse is put back into work later. It is risky to perform a partial or incomplete exam.  Often the one area not examined ends up being a problem. There is a potential conflict of interest if the veterinarian ordinarily works for the seller or is perceived as working for both buyer and seller.  Ideally the seller’s veterinarian does not do the exam.  If they do, they often require the buyer to sign a document stating that they understand the risk inherent in hiring them to perform the exam and waive this conflict of interest. If the sale does not go through, one or both parties may be angry or disappointed. Different veterinarians perform the exam differently, and have different levels of expertise with horses of different breeds, types and performing different types of work. There are risks in examining a horse under less than optimal conditions.  I only perform the exam under conditions that I am comfortable with, and usually only at my facility.  It is risky to assess a horse in unfamiliar or irregular footing because it is easy to miss a subtle problem. Pre-purchase exams have been performed by veterinarians for a very long time but given today’s litigious climate, many veterinarians try to avoid conducting them.  They commonly form the basis of lawsuits against veterinarians. If you look hard enough, you will find a problem.  The question is not whether a problem exists, it is whether the problem will interfere with the buyer's intended use of the horse. CONCLUSION In my opinion, buyers should have a pre-purchase exam performed before buying any horse, regardless of cost.  It is a smart investment.  Prior to conducting this exam the expectations and communication among all parties must be very clear.  The limitations and variables inherent in the pre-purchase exam must be understood by all parties.  When these guidelines are followed, it can be a satisfying experience for everyone. It is very important to remember that no horse is perfect.  Sometimes the most unlikely candidates make up for their less than ideal conformation and physical potential with “heart” - that intangible quality that a few equine and human athletes have.  This is hard to evaluate in the pre-purchase exam and is a subjective assessment made by the buyer.  A familiar example of the importance of this is the story of Seabiscuit. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
The Late-Term Pregnant Mare, Foaling & Newborn Foal Care From the last trimester of pregnancy through the foal’s first month is a critical time.  It is extremely important for horse owners to know what to expect.  In this article I outline several important management points and concerns during this period. THE LATE-TERM PREGNANT MARE The average mare has a pregnancy of about 335 days, but normal pregnancies occasionally last over 365 days.  The defining aspect of the last part of the equine pregnancy is that the fetus gains size and weight most rapidly during this time, doubling in size and weight during the last 4 to 6 weeks.  This means that there are great physical demands placed on the late term pregnant mare during this stage.  During their last 30 days of pregnancy many mares are sluggish, act depressed, eat less and generally just look huge and miserable. As mares near foaling, there is often a plaque of swelling (edema) that develops from the udder forward along the under-belly.  This results from interference with the mare’s circulation from the large weight of the pregnancy.  Although this can become quite impressive as foaling approaches, it usually does not indicate a problem and resolves quickly after the mare foals.  Often mare's hind legs "stock up"  or swell with the added weight, but this also usually resolves quickly after foaling. FEEDING THE LATE-TERM PREGNANT MARE My recommendation is to feed a pregnant mare as if she isn’t pregnant until she reaches the last few months of pregnancy.  At that point, I recommend gradually increasing nutrition up to the time she foals.  This may involve increased feeding of concentrates (grains) as well as more hay.  I advise feeding a vitamin supplement as well as free choice access to salt and mineral. The specifics of feeding depend on the breed and age of the mare and her condition as she enters this stage of pregnancy.  The mare uses more energy - and requires more nutrition - from the last 6 weeks of pregnancy through the first 6 weeks after foaling than she does at any other time.  For a mare that enters the last months of pregnancy in poor condition, it can be very difficult to feed enough to improve her condition.  The best policy is to provide nutrition that allows the mare to enter this stage in excellent condition. OTHER HEALTH-CARE POINTS Maintain pregnant mares on a consistent and appropriate parasite control program.  I recommend deworming with a mild dewormer in the last 30 days before foaling. We recommend vaccination with at least Encephalitis/tetanus and West Nile Virus at the same time. The late term pregnant mare should also be in good dental health. PREDICTING FOALING [caption id="attachment_6999" align="alignleft" width="300"] Waxing of Teats - Often (but not always) seen just prior to foaling.[/caption] The appearance of the udder is important in estimating foaling.  The mare’s udder typically begins to enlarge at 4 to 6 weeks prior to foaling and gradually increases in size as foaling approaches.  Immediately prior to foaling, the udder and teats are large and tight.  The color and character of the milk is a good indicator of time to foaling.  Until a day or two before foaling, the secretions from the udder are usually a clear to honey color.  A few drops can be milked into your hand for examination.  Usually within the last 24 - 48 hours the milk turns grayish and then white. “Waxing” is often referred to as the formation of a tan waxy substance that forms on the tips of the teats.  It is true that most normal mares give birth within 24-48 hours after the formation of this “wax.”  However, many mares never form wax, and so it is not a reliable means of predicting foaling.   Another sign of impending foaling is softening of the ligaments around the tail head and elongation and swelling of the vulva. There are many commercial “tests” used to predict foaling.  Most of these rely on changes in the milk composition as foaling approaches.  They can be useful tools but should not be thought of as foolproof.  Ultimately, the best way to predict foaling is to combine all of the above factors with experience.  Even then, predicting when a mare will foal can be tricky. In our practice, we use the FoalAlert system, which consists of a transmitter that is sutured just outside the vulva.  When the mare enters into labor (and the vulva separates), the transmitter is activated and the autodialer calls our cell phones.  Since we live on site, we are able to walk down to our foaling stall, and monitor the foaling process from the beginning.  We have found this system to be a reliable way to alert us when a mare is foaling.  See for more details. FOALING I feel that mares do best when they are allowed to foal in a clean pasture.   Next best is a clean large stall (at least 12’x 20’) bedded with straw, not shavings.  The cleaner the environment, the better.  Over 90% of mares have a normal delivery.  While birthing can look dramatic, it is usually over within 20-30 minutes.  The key is that the foaling should progress quickly. [caption id="attachment_7000" align="alignright" width="300"] Attended foaling by a veterinarian can ensure success, particularly in cases of a difficult or delayed foaling (dystocia).[/caption] First stage labor occurs before the foal is pushed into the birth canal and is characterized by the mare pacing nervously, lifting her tail, circling, and getting up and down.  These symptoms usually last 10-30 minutes and can appear similar to colic.  There may be some vaginal discharge during this stage.  Next, the “water bag” (chorio-allantois) is presented as a clear sac containing a red wine-colored fluid.  This is a signal of second stage labor.  The foal is now in the birth canal and things start to happen fast. Most mares lie down and strain intensely as the foal is pushed out.  Once the front feet and head present, the foal is usually on the ground and struggling to gain its feet within 5-10 minutes.  The placental membranes are often draped over the foal initially. The foal usually breaks through these quickly but if an attendant is present, it does not hurt to cut or break the membranes to clear the foal’s face.  The umbilical cord remains attached until the mare breaks it when she gets up. FOALING EMERGENCIES Most mares foal normally and without incident.  That said, when there is an emergency, quick and correct action is essential.  For this reason, a good policy is to notify your veterinarian of the foaling so that if their help is needed they are prepared to arrive quickly. If the foaling does not progress quickly and smoothly or you have any questions, it is always best to call your veterinarian then rather than waiting. Foaling emergencies include, among others, “dystocia” (difficult foaling usually resulting from improper fetal presentation or position), and premature placental separation (red bag delivery). THE POST-FOALING PERIOD A normal foal is usually up within 45 minutes from delivery, and nursing within an hour and a half.  Meconium (the first manure) is usually passed within hours of foaling.  Any straining to defecate indicates that an enema should be gently administered. The mare’s uterus begins contracting almost immediately after the foal is born.  Many mares suffer from mild uterine cramping for a few hours after foaling and will show signs of mild colic.  If these symptoms become severe, call your veterinarian immediately.  If you treat the umbilical stump, only do it once and I recommend using a very dilute antiseptic solution.  Strong solutions do more harm than good. [caption id="attachment_7008" align="alignright" width="200"] Complete & Healthy Equine Placenta[/caption] The placenta is usually passed within an hour or two of foaling.  It is considered retained (abnormal) after 3 to 4 hours and you should call your veterinarian.  A retained placenta in mares is a veterinary emergency.  If the placenta stays in the uterus for too long, it will result in a life threatening uterine infection. THE POST-PARTUM EXAM I am a strong believer in a veterinary postpartum exam.  This involves the veterinary examination of the mare, foal, and placenta at about 12 hours after a normal foaling.  At that time, we perform a physical exam on the mare, paying special attention to her general physical health, normal lactation, and the area around the vulva and anus for birthing injuries.  An exam at this stage can detect problems that, if left unchecked, can become serious. Foaling trauma to the mare is not uncommon and can be important to detect early. Problems causing colic signs are especially common in post-foaling mares and so special attention is paid to the health of the mare's gut and reproductive tract. The placenta is examined for completeness and normal appearance. All of the foal’s body systems are checked, including limb conformation. Limb deformities are common in the newborn and are best identified and managed early. Blood is drawn from the foal for an antibody (IgG) test.  The results of this test show whether or not the foal has absorbed adequate antibody from the mare’s first milk (colostrum).  Failure of passive transfer is a common and potentially fatal problem that must be detected early. [caption id="attachment_7005" align="alignleft" width="240"] Post-Partum Exam of Mare and Newborn Foal[/caption] The post-foaling exam is a great time to discuss the future management and care of mother and baby with your veterinarian. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   Would you like to learn more about late term pregnancy and foaling on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.   A few records that may interest you include:   Observation - Edema, Firm Swelling on Belly of Pregnant Mare  Observation - Foaling, Red Sac Shown, Red Bag Delivery  Diagnostic - Placental Exam  Diagnosis - Metritis, After Foaling  Skill - Perform Whole Horse Exam on Late-Term Pregnant Mare  Skill - Perform Whole Horse Exam on Post-Foaling Mare       
The Use of Complimentary or Alternative Therapies: An Equine Veterinarian's Perspective Complimentary (or alternative) therapies are commonly practiced in the horse world.  These therapies include, but are not limited to acupuncture, chiropractic, massage, homeopathy, energy work, aromatherapy, magnetic therapy and cold laser therapy.  Equine health problems that don’t have easy solutions - such as equine back problems - naturally lend themselves to many different alternative therapies.   Usually these therapies are based on modes of thinking completely different from that which underlies Western medicine. MY CONCERNS I and many other equine veterinarians have historically hesitated to advocate the use of these therapies because many of them have not been subject to rigorous scientific verification.  Some of these practitioners are trained in these therapies for human application and lack a basic understanding of basic equine anatomy and physiology.  Many of them have little understanding of the diagnostic abilities and treatments available from a licensed equine veterinarian.  Likewise, it is often very difficult to judge the efficacy of these modalities in horses.   To me, it seems like the novelty and mystique that surrounds these approaches is often their greatest selling point. One of my biggest concerns is the way in which many alternative practitioners provide treatments without first identifying the underlying problem.  They simply skip or assume the diagnosis.  If the horse recovers, the therapy is credited but there is really no way to objectively discern whether it actually helped.  For recurring problems and ones that worsen over time, the failure to secure a diagnosis may prolong the problem, ultimately increasing the cost of treatment, and may even cause unintended harm. In fact, many veterinarians have been turned off to the value of alternative approaches because we have often had to face the disaster at the end.  Much pain and suffering in horses has occurred because an owner had too much faith in an alternative cure, and the veterinarian was not called until the very end.  Horse owners should understand how difficult it is for us to be brought into the crisis too late, when the costs to save the animal have increased and the prognosis may have worsened.  We were trained to help, and that is what we always want to do. I have met and watched a number of non-veterinary practitioners of alternative therapies work on horses. I am usually disappointed by their skill and on occasion, have witnessed situations where they have harmed a horse.  I have been surprised by their lack of basic knowledge, particularly equine anatomy.  Generally, the practitioners that have impressed me are fellow equine veterinarians that have added an alternative skill to their already strong medical training. It is important to note that there is also often no accountability for lay practitioners of these therapies.  If a non-veterinary practitioner of alternative therapies charges you for a treatment that is ineffective or even hurts your horse, you have little recourse to hold this individual accountable.  A veterinarian, on the other hand, holds a professional license to practice in a given state and must answer to their state licensing board.  There are also issues regarding the legality of practicing certain modalities on equines without a veterinary license.  You should check with your state veterinary board if you have any questions. NEW DEVELOPMENTS Nevertheless, things are changing.  More and more educational programs are providing equine veterinarians with training in these areas.  It is very important for horse owners to understand the qualifications of their practitioner and what these qualifications really mean.  The information available on the Internet varies wildly, and much of it is unreliable.  Horse owners should use a critical eye in reviewing claims and studies. As in human health care, there is a place for a traditional western-approach and a place for alternatives.  The key is in knowing how to integrate these approaches for the best outcome for your horse.  Questions I would ask an equine alternative health care provider before they treat my horse are: Are you a licensed veterinarian? Did you graduate from an accredited program that teaches this therapy for application in equines? What do you think is wrong with my horse and why? Why do you think your therapy will help?  How will we evaluate the effectiveness and outcome? Should I also call my local veterinarian so that you two can work together on this issue? I realize it may be difficult to bring this team together for the development of an integrated approach, but that is the ideal that we all should be working towards.  I still strongly recommend that you start with your equine veterinarian, because he or she is the one who should know your horse in health and is therefore able to discern disease. ACUPUNCTURE & CHIROPRACTIC THERAPIES Although I grouped various alternative therapies together in my opening paragraph, the two most commonly used alternative therapies are acupuncture and chiropractic, and they deserve additional discussion. Acupuncture involves the evaluation of points on the skin which correspond to the structure and function of organs and regions of the body remote from that site.  These sites are assessed diagnostically and are treated by needle stimulation with or without injection of substances or electrical or heat stimulation.  There is great variation in technique among practitioners.  It is stated that there is local pain killer release (endorphins) at the acupuncture sites.  I have mixed feelings about the efficacy of this therapy because, in my experience, the stated benefits of acupuncture are far more profound and longer lasting than can be explained by endorphin release alone.  Nevertheless, equine acupuncture has gained wide acceptance as an effective therapy in a wide variety of situations. The International Veterinary Acupuncture Society provides education and accreditation in acupuncture to veterinarians who want to complement their Western medical training.  I periodically refer my clients to licensed veterinarians who have such training, and sometimes there is a perceived benefit. Chiropractic involves the manipulation of bones in the vertebral column such that they are operating within their ideal and have pain free range of movement.  This theoretically involves the movement of these bones by intense manipulations of the hands, called adjustments.  There is controversy over the effectiveness of chiropractic in humans, despite its widespread use.  The controversy is heightened in horses because of the mass of equine back muscle, size of the vertebrae and toughness of the support structures of the joints. I am personally skeptical about the capability of a practitioner to know whether an equine vertebrae is “out” when it is buried by six inches of dense muscle and connective tissue.  Also of concern is whether the practitioner is then able to make the adjustment, i.e., actually move the bone so that it is now fully in “in adjustment."  Finally, it is often difficult to discern whether the primary complaint has been resolved for any reasonable duration of time.  Although I remain skeptical, I do not rule out chiropractic treatments where it may be indicated as an additional complementary approach. The American Veterinary Chiropractic Association  provides education and accreditation in chiropractic therapies to veterinarians who want to complement their Western medical training.  Occasionally, I refer my clients to licensed veterinarians who have such training, and sometimes there is a perceived benefit. CONCLUSION There is so much left for the equine veterinary profession to learn.  Western medicine cannot solve all equine health care problems.  As veterinarians, it is our responsibility to help horse owners navigate the complex world of equine health care, which is constantly expanding. In cases where a traditional Western approach is insufficient, I consider alternative approaches provided that they are practiced by qualified professionals.  In my experience, that has often been by another equine veterinarian.  I am not opposed to meeting and even referring my clients to a competent lay person that has proven their knowledge and skill to me first-hand.  Keep in mind, however, that I will continue to be highly critical of the majority of these practitioners until I see more than smoke and mirrors. If you are a practitioner of equine alternative therapies and you have more information for me to consider regarding your work or any comments about my article, please contact me.   I am happy to begin a dialogue with you in the interest of improving and expanding my knowledge of equine health care. By Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
The Value of a Diagnosis Jake, a 20 year old Hanoverian gelding, showed signs of colic (looking at his side, not eating) and also seemed to be having difficulty urinating (based on his stretching out, dropping his penis as if to urinate, but having only a few drops of urine dribble out.) Jake’s owner, after doing a Google search, and armed with powerful drugs provided to her by a friend with an extensive equine pharmacy in her tack room,  treated the “colic” with Banamine® (flunixin meglumine) and administered a shot of furosemide (a prescription diuretic) to stimulate urination.  A few hours later, Jake appeared to feel better but still was not quite right, so she administered another dose of Banamine®. Jake urinated and his appetite returned, but 24 hours later his condition had worsened.  Soon he was showing more serious signs of abdominal pain, and he was admitted to an equine hospital for care. “Stretching as if to urinate” is commonly seen in horses in abdominal pain, and is often not caused by a problem with the urinary system at all.  In this case, the horse owner administered large doses of anti-inflammatories and dehydrating diuretics without understanding that there was an underlying cause (a large colon impaction). This approach allowed the impaction to worsen over time, and through dehydration and overuse of flunixin meglumine, set up another life-threatening condition, kidney failure.  In this case, there was no communication with a veterinarian and no diagnosis was made until it was almost too late to save the horse. Variations on this scenario are common throughout the horse world today. Horse owners are trying to manage problems themselves, and they delay calling a vet in order to avoid emergency visit costs. They often use the Internet to inform their decision making, and horses sometimes suffer as a result. A Medical Diagnosis is defined in Wikipedia as “an attempt at classification of a patient’s condition into separate and distinct categories that allow medical decisions about treatment and prognosis to be made.”  In a 2005 article on the process of veterinary diagnosis, Dr Carl Osborne states:“Just as no two individuals are exactly alike in health, so neither are any two alike in disease.” In one horse, infection with the Strangles organism may cause a high fever and severe depression but only mild cough and swelling under the jaw. Another horse may only have a mild fever, but have very swollen lymph nodes and a severe cough. Veterinarians observe these different manifestations frequently, and must still be able to diagnose in the face of this uncertainty. This is the “art” of practice.  Veterinarians use the method of “differential diagnosis”, which is based on identifying a list of candidate diseases or conditions that might possibly be causing a clinical sign. They then eliminate possibilities through the use of diagnostic tests, or by judging response to symptomatic treatment. Upon reaching a diagnosis, veterinarians consider the potential treatments for that diagnosis, and select the most appropriate. There is generally a body of knowledge associated with a diagnosis that supports using particular treatments. Today, we all have access to the same vast body of information on a subject via the Internet. The problem is how to use that content most effectively. Horse owners often begin the search by inputting their own observations as search terms. Google might return a million search results, but these are not organized based on relevance to a situation (and all of them aren’t necessarily from reliable sources either).  In contrast, there is a lot known and a lot written about equine diagnoses.  Once your vet provides an accurate diagnosis (a name for the problem), and some guidance, then the Internet can be used to deepen your understanding of your horse’s condition. Here are some suggestions that should increase the likelihood of making a correct diagnosis and treating your horse effectively. Communicate with your vet soon after you observe a problem. They can guide you as to whether you can treat symptomatically or need to pursue a diagnosis.  Together, you can discuss your options and their associated costs. Be observant, and communicate your observations to your vet effectively. Photos and videos can help your vet quickly determine the best course of action and whether the horse needs to be seen. Learn to perform basic treatments so you can provide required follow-up care. Once you and your vet have chosen a treatment plan, talk to them about how to assess its effectiveness and how to monitor and communicate your horse’s progress. Ask your vet to recommend further Internet resources that might help you expand your understanding. The Internet, when it is used appropriately, is a wonderful tool for enlightenment on equine veterinary medicine. But to do your horses justice, recognize the value of a diagnosis, and differentiate it from your own observations. The person that can bridge the gap between your observations and a diagnosis is your veterinarian. Jake survived, but ironically, his veterinary bills were much higher than they would have been if he had been properly diagnosed and treated early in the course of disease. He will live out his life with only one jugular vein, and only about 25% of his original kidney function. He is maintained on a special diet and strict management to prevent worsening of his kidney problems, and he will always require periodic veterinary monitoring. Douglas O. Thal DVM  Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCOriginally published in The Horse Magazine, October 2012 First Place Winner in Personal Single Column, Circulation over 20,000 (Print) Category - American Horse Publications Annual Award Program 2013   
Understanding & Managing the Rising Costs of Equine Veterinary Care This article addresses a subject that I deal with on a daily basis – the rising cost of providing quality equine veterinary care.  It is a topic many horse owners and veterinarians find uncomfortable, and is too rarely addressed. These days, most services provided by modern and well-equipped equine veterinarians (from routine care to an unanticipated crisis) are costly.  How can you, the horse owner, obtain the very best veterinary care for your horse without being financially overwhelmed? The answer lies first and foremost in educating yourself and in maintaining good communication with your equine veterinarian.  As discussed below, these points go hand in hand. WHY IS EQUINE VETERINARY MEDICINE SO EXPENSIVE? The overhead costs associated with running a full service equine veterinary facility are higher than for small animal practices and rise each year. To keep businesses running and be compensated fairly, equine veterinarians must pass these costs onto clients.  Let’s start with the basics: Veterinary charges for horses are much higher than those for small animals simply because of their size.  The same amount of medicine necessary for effective treatment of a small animal must be multiplied on a scale of 10 to more than 100 times for an effective dosage in a horse. Likewise, the facilities needed must be much larger and specialized to handle horses.  Equine veterinarians that offer full-service care must invest in real estate large enough to host a hospital and associated structures, including stalls, round pens, turnouts, and more. For mobile vets, the cost of being on the road is high, mostly in terms of travel time. As for any small business, the basic operating cost of doing business (overhead) is high for veterinary practice and continues to increase.  Equine veterinary practice has especially high overhead. Relatively large inventory, higher rates of liability insurance, utility expenses for complex and large facilities, fuel and maintenance costs for mobile units, specialized staffing, and all other costs are high and continue to increase. Unlike small animal practice (in which many regions have 24-hours emergency centers), most equine vets handle their own after-hours emergencies. Vets and support staff must be compensated for their extraordinary accessibility and availability. Dedicated, highly trained equine professionals are hard to find and demand higher wages for their higher level of equine training, and commitment to after-hours emergency care. As is the case in human healthcare, the trend toward increasing specialization in equine veterinary care results in increased cost. Equine dentistry, surgery, anesthesia, imaging, and treatments have all reached new levels of sophistication in private practice, and new levels of cost.  Highly sophisticated and costly MRI, nuclear medicine, and other specialized are increasingly becoming the standard in private practice.  While all of these advances mean more options for horse care, they also account for greatly increased cost. This trend toward specialized and expensive services in private practice is driven to a great extent by better-informed horse owners that demand the best health care for their horses. However, as in human healthcare, there is a Catch-22: Someone has to pay for this higher level of care. Drugs purchased through your equine veterinarian are typically more expensive than those purchased through veterinary supply catalogs.  This difference relates to the costs of inventory, labor, administrative costs and quality control, which are relatively much higher than for a large supply company.  A responsible equine veterinarian is constantly trying to maintain a delicate balance by anticipating his or her client’s needs, keeping certain drugs available for immediate dispensation, yet trying to keeping the overhead cost for unused inventory at a manageable level. Several real advantages in buying products from your veterinarian are convenience and 24-hour support and consultation.  Likewise, emergency services provided by equine veterinarians reflect the fact that being available 24/7/365 requires major lifestyle compromises that require appropriate compensation. 10 WAYS TO ENSURE YOUR HORSE'S GOOD HEALTH & REDUCE YOUR COST Given these high and rising costs, what can you do to control the cost of keeping your horse healthy and performing at a high level? 1. EDUCATE YOURSELF.  The single greatest reason why clients spend excessively on their horse is lack of knowledge and preparation.  Your equine veterinarian can help you choose the right products and services and can direct you toward reliable educational resources.  In a complex world of expensive "miracle" supplements and bogus claims, your veterinarian can guide you in basic care, preventative medicine, and the healthcare that your horse really requires.  Many expensive equine products actually have no benefit and some may even be harmful. Vendors can make any claims they want about their products. There is almost no regulation and many promote their products shamelessly and misleadingly.  View these products with a critical eye and when in doubt, ask your vet for advice. 2. PROVIDE GOOD BASIC CARE.  Invest in the basics, including a clean and safe environment, proper fencing, shelter, turnouts, quality hay and grain, water, and hoof care.  I can’t tell you how often complicated and expensive health care issues arise simply because good basic care has not been provided. 3. ROUTINE & PREVENTATIVE CARE.  Ideally, your veterinarian sees your horse twice a year for spring and fall work. Vaccination is only a small part of this. The real value lies in the consultation that your vet provides during that visit. Your veterinarian performs a dental exam (and dentistry only if needed), and becomes familiar with your horse in health and with your needs and desires.  It is important that a veterinarian know your horse in health, so they can better evaluate your horse when a health care issue arises. 4. COMMUNICATION.  Establish good communication with your veterinarian right away when you perceive a problem. Contact them even when you have general questions about your horse’s care. Always promptly call if your horse has received recommended treatment and is not responding or seems to be doing poorly.  A minor adjustment in treatment may be all that is needed to turn things in the right direction. In today’s world, you can effectively communicate so much through a good photo or short video taken with a smartphone. Use this technology to help you communicate efficiently and effectively with your vet. 5. RECOGNIZE THE VALUE OF A DIAGNOSIS. When you observe a problem with your horse, prompt consultation with a knowledgeable professional is usually less expensive in the long run than purchasing expensive supplements or utilizing alternative therapies without a diagnosis. A diagnosis gets to the heart of the problem, and is essential to choosing the correct and most efficacious treatment plan. 6. ACT QUICKLY.  Contact your equine veterinarian the moment you notice a problem.  They can help you determine whether examination is necessary.  If you don't call, your horse may well improve on it’s own, but the problem might also worsen.  This gamble could increase the final veterinary bill and worsen the prognosis. Recognize signs of common emergency conditions: Always call your veterinarian immediately if you suspect your horse has colic, choke, foaling problems, eye problems, severe lameness, and wounds located near joints or that seem otherwise complicated or deep. With early veterinary contact, some of these problems may be successfully managed with a simple phone call or simple treatments rather than life saving, expensive heroics later on. The key is communication and mutual trust. 7. OPTIONS & ESTIMATES.  There is rarely a single solution to an equine health problem.  Ask your veterinarian for different treatment options and an estimate for the cost of each.   Although expensive treatments exist and are becoming more and more available, they are not necessarily the best option in all circumstances. One of your vet’s most important jobs is to inform you of the range of options available to you and the costs and benefits of these options.  It can be difficult to make these decisions in the moment of crisis. For that reason, I encourage horse owners to consider their general approach to this question before such a moment arrives. Become informed by reading articles such as "Colic Surgery: What Horse Owner's Should Know," which encourages horse owners to consider what they would do when faced with this difficult decision beforehand. 8. CLINIC VS. FARM CALLS.  Transporting your horse to an equine veterinary facility can be less costly than a farm call, which includes the veterinarian’s driving time, vehicle mileage and the ever-increasing cost of fuel. If you don’t have a trailer, make a friend with someone who does.  Many specialized services can often only be delivered in a clinic situation. On the other hand, recognize that a farm call is a luxury that is becoming more and more expensive to provide. 9. EQUINE MEDICAL & MORTALITY INSURANCE. There are a number of insurance companies that provide equine insurance, which can be a lifesaver in a moment of crisis. The equine supplement company Smartpak provides colic treatment and surgical compensation programs to customers feeding their supplements, if they conform to certain guidelines, including basic services provided by a vet.  See 10. SPECIALIZED FINANCING.  Several companies offer a line of credit for health care expenses that can be used for veterinary care.  Given how difficult it is for veterinary practices to finance their clients, we encourage horse owners to consider securing this financing instead. You can apply for a line of credit at the time it is needed or beforehand.  Nevertheless, it is important to fully understand the terms of repayment and compare the fees, penalties (especially for late payments), and interest rate to your other available funding sources. Carecredit is an example CONCLUSION Horse ownership is expensive and proper veterinary care accounts for a significant percentage of that expense.  Ultimately, the relationship you have with your equine veterinarian will guide you and your horse down a balanced path.  Use them as a sounding board to help you determine the level of care you are comfortable with, and discuss the costs of these services frankly and openly. By Douglas O. Thal DVM Dipl. ABVP   Board Certified in Equine PracticeThal Equine LLC Last Updated August 2014   
Vesicular Stomatitis: What Horse Owners Should Know Vesicular Stomatitis ("VS") is a viral disease that affects horses, and less commonly cattle, pigs, llamas, alpacas, and other livestock. We see periodic outbreaks of Vesicular Stomatitis in our region of the Southwest.  VS is a reportable disease, meaning that when a case is suspected by a veterinarian, we are required to involve the United States Department of Agriculture: Animal and Plant Health Inspection Service (USDA: APHIS). Reporting is required because VS resembles "Foot and Mouth Disease" in cattle, which is greatly feared in the livestock industry.  When VS is confirmed in the United States, non-affected states and most foreign countries initiate transport embargoes to prevent spread into their territories.  Movement of livestock is hindered and affected premises are quarantined.  The entire livestock industry is adversely affected.  After reporting a potential occurrence of the disease the animals in question must be inspected by USDA:APHIS.   Laboratory work is performed to determine whether or not the animal has VS. Premises that have confirmed VS are quarantined for a specific period of time after the lesions and clinical signs resolve. VS  occurs exclusively in the Americas.  The last severe outbreaks in the Southwestern United States occurred 2004, 2005, and 2006, and smaller outbreaks occurred in 2009 and 2010.  The disease is more common in southern Mexico and Central and South America.  It is likely that a warmer climate in the last 15 years has favored the presence of the disease here and is at least partly responsible for more frequent outbreaks. SIGNS OF VS The classic sign of VS is ulcers and blisters of the mouth, lips and tongue.  Lesions are occasionally seen on the coronet bands (the hairline of the hoof) and on the udder or vulva of females and on the penis and sheath of males.  The mouth lesions generally are associated with salivation, loss of appetite, and depression.  If you inspect the mouth, you might see these ulcerated areas. VS is thought to be spread by direct contact between saliva of infected animals and other horses, as well as by biting insects.  The precise means of spread is not known.  Following exposure to the disease, it usually takes 1-3 days for signs to appear.  The disease process is fairly short and once lesions appear, there are usually no new lesions formed after 3-4 days.  Lesions usually resolve in 10-14 days. VS is generally not a very serious disease in horses. That said, the lesions are often very painful and can cause difficulty eating.  Virus shedding (contagiousness) is usually limited to the first 6-7 days after exposure.  Despite this, regulations usually dictate that horses are quarantined for 30 days after the last lesions heal. OTHER IMPORTANT POINTS Horses are more susceptible to infection than other livestock species. Pastured horses have a much higher rate of disease than stabled horses.  It is unclear why this is but may relate to exposure to the infecting insects or to grazing itself. The infection rate is high in a group of horses but many horses do not show signs of disease.  This relates to the immunity of some horses versus others.  Usually 20%-30% of horses in a group will show signs of disease. Horses less than one year of age have a lower incidence of infection than older horses. WHAT YOU SHOULD DO IF YOUR HORSE IS SHOWING SIGNS OF VS Call your veterinarian if you see suspicious signs in a horse, including salivation or ulceration of mouth, lips or tongue.  Your veterinarian will either come out to see the horses or put you in contact with the State Veterinarian’s office.   Any nursing care necessary for affected animals should be handled by you and your regular veterinarian. It is important that a licensed veterinarian see horses showing signs.  Other problems may mimic VS and it is important to tell the difference between these.  Grass stuck in the mouth, certain toxins, and blister beetle toxicity from hay can cause oral ulcers too. There is no vaccine and, as with many viral diseases, there is really no treatment other than time.  If your horses cannot eat or drink, supportive nursing care may be necessary.  In the event that your horses are not eating or drinking, please call your vet right away to ensure that your horse gets the care it needs. Practice good fly control, both during the day and evening.  Stable horses as much as possible to reduce chance of infection. To prevent spread of disease, disinfect tack, equipment and premises that have come into contact with affected horses.  Use 1:10 bleach and water sprayed on all surfaces.  Let stand 15 minutes and rinse. VS is generally a summer-time problem.  Colder weather in fall and early winter usually ends an outbreak. Keep in mind that VS is transmissible to people and generally causes flu-like symptoms.   Although the signs are usually mild, it is important to take precautions.  Wear gloves when handling animals affected by the disease or showing compatible clinical signs.  Wash your hands and arms with disinfectant soap following contact with affected animals. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011  
What? You are going to ROLL my horse? Non-Surgical Correction of Left Dorsal Displacement with Nephrosplenic Entrapment Case Report from Thal Equine LLC January 2015   Friday, an 11-year-old Thoroughbred gelding, arrived at Thal Equine showing signs of abdominal pain (colic).  He had not responded to pain relievers and fluids by stomach tube given by the veterinarian at the farm. Upon arrival at our clinic, Friday still exhibited mild signs of abdominal pain; occasionally pawing, stretching and looking at his side.  He looked visibly bloated, and he had poor intestinal motility, especially on the left side of his abdomen.  While we continued to treat him for pain and dehydration, our most important task was to identify the Condition Causing Colic (CCC), i.e. the diagnosis. COLIC DIAGNOSTICS When a horse is experiencing abdominal pain (colic), it is the veterinarian’s job to identify the underlying cause, the Condition Causing Colic (CCC). Only if we understand the nature of the CCC, can we best identify the treatment options. Depending on the diagnosis, the appropriate treatment may be simple, such as pain-relief and fluids by nasogastric (stomach) tube. Cases that don’t respond to these treatments might require more aggressive treatment such as hospitalization with IV fluids and ongoing pain relief and careful monitoring. About 5-10% of horses showing signs of colic require colic surgery. The colic exam is a special physical exam veterinarian's do to look at certain aspects of the horse’s health that reflect the intestinal and cardiovascular systems. It considers the complex anatomy and function of the 30-meter (100 feet) long equine gastrointestinal tract. The goal is to determine which anatomic region(s) are affected, and how. We also also use a group of standard diagnostic procedures and tests to gather more information and reach a diagnosis (or at least have a better understanding of the problem) so that we can recommend the most appropriate course of treatment.  The amount of and quality of information gathered during a colic exam depends on the veterinarian’s knowledge and experience, and the diagnostics available. An important factor that we always consider is the severity and duration of the horse’s pain. The rectal exam is a very important diagnostic test for horses showing colic. The veterinarian inserts their gloved arm into the horse’s rectum and feels the abdominal organs, including the regions of intestine, through the thin rectal wall. In Friday’s case, the results of the rectal exam were abnormal. We could feel the left colon caught in the space between the kidney and the spleen, hanging on the ligament that joins those two organs.  Based on this finding, we believed that he was suffering from a condition called Left Dorsal Displacement of the Large Colon, with a Nephrosplenic Entrapment. Only a small percentage of horses suffering from colic have this condition. WHAT IS A LEFT DORSAL DISPLACEMENT WITH NEPHROSPLENIC ENTRAPMENT? In a normal healthy horse, the spleen rests against the left abdominal wall and is connected to the left kidney by a short, thick sheet of connective tissue, called the nephro-splenic ligament. Sometimes, however, the very mobile, left part of the large colon (a bulky double horse-shoe shaped organ that weighs about 100 lbs) slides between the spleen and the body wall (called a left dorsal displacement), and can further become entrapped on top of this ligament, within the nephro-splenic space.  When the colon is trapped in this position, it is known as a “nephrosplenic entrapment. No one really knows why this or many other intestinal displacements take place in horses. In this case, the prevailing wisdom is that abnormal movement (motility) of the colon causes dysfunction and gas accumulation within the colon, which then floats up or is pushed up into the abnormal position. Another hypothesis is that a feed impaction starts the abnormal movement of the colon. Abdominal ultrasound is another very useful test for supporting this diagnosis. In this case, we used abdominal ultrasound to help us visualize the left upper region, and this confirmed our diagnosis. Friday’s spleen could not be seen in its usual position against the body wall. In fact it was pushed well over to the right of his abdomen, and his left kidney was hidden behind a gas and feed-filled colon. TREATMENT PLAN – JOG, ROLL OR SURGERY? In many cases of intestinal displacement, surgical correction is required. In some “mild” displacements, medical therapy (IV and oral fluids and nursing care) may allow the colon to move back into position. But when we diagnose nephrosplenic entrapment, we usually try one of several special treatments to get the colon unhooked from the ligament. One common approach to correcting a nephrosplenic entrapment is sometimes called the “drug and jog” approach.  A veterinarian administers medication (phenylephrine) to shrink the spleen, and then the horse is jogged and exercised for about 10 minutes.  The theory is that this movement helps to jostle the colon back into its proper position.  Although some veterinarians favor this approach, and it has been reported to have a high success rate in the veterinary literature, I personally have had mixed results with it. But I do often try this approach first because it is easy.  If correction does not take place within a very short period of time though, I move on. In Friday’s case, the “drug and jog” approach did not work, so I recommended the rolling procedure next. The “Rolling Procedure” is a non-surgical treatment that, when performed correctly, is thought to return the colon to its proper position within the abdomen in about 70% of cases. In our practice, the rolling procedure has been a great tool for treating nephrosplenic entrapment. Before we performed the rolling procedure on Friday, I was careful to explain to his owner the potential limitations and complications of the procedure: There is a very small risk associated with short-acting general anesthesia and recovery. In some cases, the rolling procedure simply does not work. The colon stays trapped and must be manually repositioned at surgery. In some cases, other intestinal problems are also present. These are not helped by the rolling procedure and so they persist.  There is a small chance of rupture of the tight, distended colon as the abdomen is jostled around. In rare cases, this procedure may actually convert the simple entrapment of the colon to a twist. In these cases, the horse becomes more painful, and we immediately proceed to colic surgery if it is an option. NON-SURGICAL CORRECTION – A/K/A THE “ROLLING” PROCEDURE Before I describe how veterinarians do this, understand that this procedure is only to be performed by a qualified veterinarian who is confident in their diagnosis of left dorsal displacement of the large colon.  It is not a proper treatment for any other condition or diagnosis and could even be harmful. First, we medicated Friday with phenylephrine to shrink his spleen.  Theoretically, this gives the large colon more space within the abdomen within which to move back to its proper position.  Next, we anesthetized him using short-acting general anesthesia and gently lowered him to the floor of our padded stall.  Starting with his right side down and using an electric hoist to help us move him, we rolled his body through a certain sequence. This sequence is intended to move the colon out of its trapped position and back to its proper position. Although the image above does not show it, we usually continue to roll a horse back over their chest and until they are left side up again, so we can examine the abdominal space on ultrasound while a horse is still lying down. We leave the horse in each position about 1-2 minutes, and we gently but firmly jostle their abdomen during each stage of the rolling. After the sequence is done, we determine whether or not the problem is fixed using repeat ultrasounds and rectal exam performed while the horse is still down. In this case we rolled Friday three complete times! We almost gave up after two failed attempts, but decided to try it one more time. We were committed to trying to save Friday from colic surgery, if possible.  The third time was a charm! In 15 minutes after the end of the rolling procedure, Friday was back on his feet. Once he became stable, we walked him to a hospital stall and gave him IV and nasogastric fluids. He rapidly improved. He started passing large quantities of gas, his abdomen quickly deflated, and his intestinal motility improved. He quickly began searching the stall floor for feed. He continued to do well and returned home two days later.  Had the rolling not been successful, the only alternative would have been colic surgery. THE RISK OF RECURRENCE & PREVENTATIE ABLATION SURGERY Although treatment was a short-term success, the problem is that this displacement/entrapment recurs in about 10% of horses. In this case, there were factors in Friday’s history and exam that we felt made it even more likely that it would happen again. After discussing this risk of recurrence with the owner, I recommended a surgical procedure to prevent entrapment in the future. A week later, Friday was transported to the Colorado State University Veterinary Teaching Hospital, where he had a special standing surgical operation performed to close (ablate) the nephrosplenic space. This surgery is performed through several small incisions in a horse’s left flank, using a laparoscope to visualize the repair. The space is actually stitched closed, completely closing it, to prevent the colon from becoming entrapped there again. The word ablation means removal or destruction of something, the nephrosplenic space in this case. After the procedure, the left colon can, however, still freely move between the body wall and spleen CONCLUSION Friday is now happy and doing well at home. He will recuperate for about 6 weeks and should be able to return to full work soon. In this case, with a rapid and correct diagnosis we were able to successfully perform a specific non-invasive treatment. It saved Friday from undergoing traditional colic (abdominal) surgery, a much more invasive and costly procedure that would have required a much longer lay-up period. Now, with the nephrosplenic space closed, there is very little worry of recurrence. [caption id="attachment_7263" align="aligncenter" width="300"] Friday and his owner, Erin[/caption] Coauthored by Doug Thal DVM DABVP & Sophia Krajewski DVM of Thal Equine LLC, January 2015 
Winter Health Care Basics for Horses Generally, horses are not used as heavily during the winter months, but their proper care is every bit as important as in other seasons.  Winter provides different stresses on horses than they experience during the rest of the year, and horse owners should know the basics before winter arrives. HOW COLD TOLERANT ARE HORSES? Given some protection from the wind and wet (shelter), a healthy horse can easily tolerate -40 degree Fahrenheit temperatures.  The single greatest factor allowing horses to be so cold tolerant is their size.  There is a simple scientific reason for this: The larger an animal is, the lower the surface to volume ratio. In other words, the heavier the animal, the less skin surface area per pound is exposed to the outside world, so the slower the body temperature responds to changes in air temperature.  Young foals lack this surface to volume ratio, but have much higher metabolisms that compensate otherwise. The horse's winter hair coat is a very important barrier against cold.  It is a surprisingly sophisticated system that traps an insulating layer of air against the skin.  The hair coat functions well as long as it is “fluffed” and stays dry.  Wind and rain act to flatten this system and reduce the barrier to cold.  Muscle and fat also play very important insulating roles. A horse that goes into winter in good flesh is more able to tolerate cold weather than one that goes into winter thin.  A fit horse of good body muscle mass and a normal layer of fat has advantages over an unfit horse who has a thick layer of fat and less muscle. There is a critical temperature at which healthy horses must produce extra heat to maintain their body temperature.  This critical temperature depends on many factors, but is around 15 degrees Fahrenheit.  Horses with health problems, thin horses, and those with little coat have higher critical temperatures.  The extra heat required to maintain body temperature uses extra energy, which must come from extra feed. FEEDING HORSES IN WINTER There is a lot of confusion regarding how much more feed horses need during the winter months.  Horses do not need more feed until the temperature averages at or below their specific critical temperature, which depends on the factors discussed above.  Generally, horses need about 15-20% more feed for every 10 degrees average the environment is below their critical temperature.  In many areas, the average 24-hour temperature is above the critical temperature for a healthy horse, meaning that extra feed is not necessary.  Unless it is an unusually cold winter, here in the desert Southwest horses generally do not need much more feed in the winter. TIPS ON WINTER FEEDING Less mature, high quality grass or mix hay should form the basis for the healthy horse diet.  Less mature hays are more palatable and hold water better in the gut.  Over-mature, straw-like hay may create problems with intestinal impaction. A simple and safe bet for winter feeding is to simply increase grass or mix hay in the diet 20% over warm weather feeding amounts.  Make any feeding changes gradually, over a few days. Whatever method of feeding you choose, do not vary it with daily weather changes.  If you do choose to change it, simply feed a little more hay, not grain. Once cold weather sets in, it is difficult to put weight on horses, especially thin ones.  It is easier to maintain a horse’s good flesh in the winter than it is to put weight on a thin horse. A long winter hair coat makes it more difficult to assess body condition visually.  Regularly check condition by using your hands to feel fat and muscle cover on your horse’s ribs and bones of the pelvis and spine, through his winter hair coat. Winter pasture is much lower in nutrients and is often sparse.  Horses must work harder for less nutrients.  Keep this in mind when wintering horses on pasture. Easy keepers may do well on grass hay alone.  Hard keepers or those in work will require alfalfa hay or concentrated feeds (grains or pelleted feeds) as a supplement.  How much of these supplements required depends on that horse’s specific needs. Only feed as much grain as needed for maintenance. One way to increase energy in feed without increasing grain is with high-fat rice bran or corn oil.  Feeding a few ounces of corn oil, top-dressed on a small amount of grain, can provide as much energy as another scoop of grain, without the carbohydrates. All horses should have access to a mineral block or loose minerals. WHAT ARE "HOT FEEDS"? It is a misconception that a “hot feed” (like corn) produces extra body heat and therefore should be fed to wintering horses.  A “hot feed” is a horseman’s term for a feed with high caloric content.  The term generally refers to grains (especially corn) or rich hay.  Corn has a large number of calories per unit weight.  High caloric content means high energy but does not translate to body heat production.  Irregular feeding of “hot feeds” may cause other health problems, like colic or laminitis.  The best feed for heat production through digestion is hay.  Hay is broken down in the hindgut by the process of fermentation.  This directly produces heat, which is an important part of body heat maintenance. WATER Winter is a critical time to provide plenty of access to clean water.  Certain types of colic are more common in winter.  This may relate to decreased water consumption during the winter.  Snow does not provide adequate water for horses.  Horses fed hay drink more water than pastured horses because of hay’s low water content.  Horses will drink more warm water than ice-cold water.  Water can be kept warm with electric tank heaters, or different designs of insulated watering tubs. If you do not provide warmed water, you should break ice at least twice daily.  Horses often drink right after a hay meal, so their water source should be available to them then.  Electrolytes added to feed or supplemented in paste form may increase water intake, but are usually not needed. GENERAL HEALTH CONSIDERATIONS Horses should be properly vaccinated, because the incidence of certain diseases can be higher during winter. Horses should be current on dentistry.  Proper dental function is critical to proper feed utilization, which is especially important for wintered horses. Winter is an important time for maintaining proper parasite control. Winter often brings alternating wet and frozen footing, which can mean a higher incidence of foot problems like sole abscesses. Slick, frozen footing can result in slips and falls.  Because of this, we see a higher incidence of certain fractures and other injuries during the winter. Most horses (those that won’t be used heavily) should have their shoes pulled for winter. Snow-covered cattle guards are a real risk.  Horses try to cross cattle guards obscured by drifting snow and fall through, suffering severe trauma.  Keep your horses away from cattle guards during the winter months. SPECIAL CONSIDERATIONS Late term pregnant mares, growing youngsters, old horses, and horses with health issues must receive extra attention during winter for the reasons we have discussed.  Older horses are less able to resist winters stresses in general.  Be sure that they go into winter in good condition, and that their condition is monitored carefully.  Once an older horse loses condition it is difficult to regain, especially during the winter months.  A healthy horse over 20 years old should be fed about 25% more than a horse in its prime.  Pregnant mares generally only require special nutrition in their last trimester of pregnancy.  The key for managing foals in cold weather is to ensure their general health and nutrition and to provide some shelter from wind and moisture. HORSES KEPT IN USE OR WORK DURING WINTER If horses are used through the winter, then using rim pads or special snow pads may prevent buildup of ice on the soles.  Horses can be exercised intensely even at very cold temperatures, but warm ups and cool downs should be about 50% longer to account for cold muscles, tendons and ligaments.  Exercised horses should be dried and brushed well after use. BLANKETING HORSES IN WINTER Healthy horses do very well without blankets, even in the very coldest weather. The major exception to this is horses that have been clipped for performance or work during the winter months. Think of blanketing as a commitment to take over the horse’s intricate control of its own body temperature.  Blankets have the potential to cause problems, so the blanketed horse must be carefully monitored.  Horses can become tangled in their blanket straps or blankets can shift, causing problems. It is important to remove the blanket routinely to monitor condition and watch for skin problems.  Overheating under blankets is a common and potentially serious problem. CONCLUSION There is still much science that remains to be learned about winter horse care. The bottom line is that each horse must be managed according to its individual needs and with common sense.  A good guideline is to provide excellent basic care, keep things as simple and regular as possible, and let nature do the rest. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCLast Updated August 2011   
Worms vs. Drugs: The Fundamentals Research over the past 10 years has confirmed that indiscriminate deworming leads to selection for worms resistant to common deworming compounds.  Because of this, “targeted deworming” based on fecal analysis results has become the industry standard. This approach reduces the total amount of chemical used and better matches drug to worm.  But when it comes to equine parasite control, controversy and confusion remains, and there are still many people still “doing it the old way”. In order to be part of the solution to the resistance problem, and at the same time to give your horses the best care, it is important that you know the basic characteristics of the common equine parasites, as well as the basic mechanism and effects of the common deworming compounds. THE ‘CLASSIC’ PARASITE LIFE CYCLE While there are great differences among the important internal parasites, they share a fundamentally similar life cycle. They all spend part of their lives in the horse, and part of their lives in the environment. The adult worms live in the intestine of the horse, where they lay their eggs. These eggs are passed from the horse into the environment in the manure. On pasture, the eggs hatch over time into larvae. The larvae develop to a point at which they are “infective” and are once again ingested by a horse. The infective larvae mature within the horse into adult worms, and the cycle repeats itself. Martin Nielsen, DVM PhD, a leading researcher in equine parasitology, and assistant professor at the University of Kentucky Gluck Equine Research center says: “In the environment, parasite eggs flourish and develop into infective larvae when temperatures are between 45° and 85° Fahrenheit.  When these conditions exist during the year depends on location but one thing we know is that eggs actually survive much better in cold than hot conditions. There is no such thing as a killing frost for these parasites.” THE WORMS LARGE STRONGYLES. Historically, large strongyles were considered the most important equine parasites. They were common, and they caused a particularly severe problem in horses called thrombo-embolic colic, in which worms enter, damage and block the arteries that supply blood to segments of intestine. Over the past 40 years, much of our parasite control effort went into eliminating these worms, and to a great extent, we were successful. Thrombo-embolic colic, and these parasites, are now rare in managed horse populations. But those same efforts have caused severe drug resistance in other worm populations. SMALL STRONGYLES (Cyathostomins). These worms are common in almost all horses. They are small, threadlike worms that can sometimes be seen in manure after deworming. Small strongyle and large strongyle life cycles have similar “classic” life cycle as described previously, but small strongyles show one important difference. Their larvae can burrow into the wall of the intestine and stay there for extended periods in a dormant state, until the environment is optimal for reproduction, at which time they emerge. This makes the species more adaptable. It also protects them from most of our worming compounds, which cannot penetrate the intestinal wall well enough to kill the larvae there. Small strongyles are now resistant to many of our common worming compounds. The only good news is that these parasites do not cause severe disease unless they are present in very large numbers. ASCARIDS. The most important Ascarid roundworm in horses is Parascaris equorum, a large, pale worm that looks like a large bean sprout. Ascarids can grow to 15” long but are usually smaller. They are considered the most important parasite of growing horses. Ascarid eggs are extremely resistant in the environment, living for years on pasture. When temperatures warm above 45 degrees, the larvae develop within the egg to an infective stage.  The horse then ingests these infective eggs. The eggs are coated with a sticky substance that enables them to adhere to all types of surfaces, including the mare’s udder.  Mouthy, curious foals pick them up from these surfaces. The eggs hatch in the small intestine, and the larvae penetrate the intestinal wall there and enter the bloodstream. They enter the liver, then go to the lungs, then back to the intestine, where they grow to be adults and lay eggs. The whole cycle takes about 2½ months. In large numbers, these parasites can cause ill thrift and poor growth. When a de-wormer is given to a heavily parasitized youngster, large numbers of these worms can die suddenly in the intestine and drift downstream, forming a tangled mass that blocks the intestine and causes severe abdominal pain. This life threatening episode is known as “Ascarid Impaction”. Cleaning up the environment helps reduce the number of eggs a foal ingests, but it is almost impossible to prevent infection in young horses. Craig Reinemeyer, another internationally respected equine parasitologist and researcher says: “The de-wormers used against ascarids are not effective against early stages of the parasite; they only kill adults, so it is important to wait until 60-70 days before worming young horses.” Foals should receive about four anthelmintic treatments their first year, probably all benzimidazole.  Ascarids are showing increasing resistance to the ivermectin class and so it may be inadvisable to use it in youngsters. PINWORMS. Unlike the worms discussed above, pinworms do not cause serious disease. Pinworm adults live in the large intestine near the anus. Instead of laying eggs that are passed into the environment in the manure, female pinworms actually leave the intestine and lay the eggs on the skin of the anus. The eggs are irritating to the skin there and cause itchiness. In rubbing their tail base and anus on stall walls, fences, trees, etc, horses deposit the eggs in the environment. The next horse to lick the object will ingest the eggs and the cycle will repeat itself. Historically, pinworms have been more of a problem in younger horses, but today they are seen much more in adult horses too.  According to Reinemeyer “There is evidence that pinworms are developing drug resistance and new approaches to managing them are needed.” TAPEWORMS.  These are very different from other equine internal parasites and are not affected by most of the common de-wormers. One important difference is that tapeworms have an indirect life cycle. To complete their life cycle, they must spend some time within a second “indirect host”, a tiny Oribatid mite. These mites live in large numbers on pasture and are regularly eaten by horses when they graze. The mites ingest the tapeworm eggs shed by the horse. These eggs hatch into larvae within the mites, and the larvae grow. Grazing horses eat the mites containing what are now infective larvae. The larvae are released in the intestine as the mites are digested. They travel to a specific location within the horse’s intestine, the point at which the large and small intestines meet (called the ileo-cecal valve). Here the larvae mature into adults over 6-10 weeks, and begin shedding segments containing eggs which again are passed in the manure. Our ability to diagnose these parasites is poor. “They are usually not diagnosable using fecal floatation techniques and the available blood tests have some problems too.” says Dr. Reinemeyer. The mite hosts are found only on moist, growing pasture. Tapeworms are thus more common in these areas and should not be a problem in dry lot situations and arid environments. Tapeworms are thought to contribute to a condition causing colic- irritation and blockage of the ileo-cecal valve area where they gather. But they can live in small numbers there and usually not cause a problem. BOTS.  Bots are not actually worms, but are the larval stage of a fly that at first glance looks like a honeybee.  Bot flies buzz around horse’s legs and lower bodies, depositing their sticky pale eggs on the hair. The adhered eggs irritate the skin, causing the horse to lick the area and ingest the eggs. Once eaten, the eggs quickly hatch within the mouth, and the larvae stay there for several weeks until they are swallowed and attach to a very particular location within the stomach. The bot larvae spend the winter months attached to this location in the horse’s stomach. When conditions are right in the spring, the larvae release and are passed into the environment in the manure. They burrow into the soil and pupate, finally emerging later as adult flies to lay eggs and repeat the cycle. The internal larval stages of bots probably cause no real problems for horses. It is not uncommon to find hundreds of the larvae attached to the stomach in a healthy horse. Probably the biggest problem associated with bots is the annoyance caused by the egg-laying adult flies. The only wormers that control bots are moxidectin and ivermectin. But aggressive use of these drugs to eliminate bots probably also increases resistance in other parasites. THE DRUGS Management techniques are the true cornerstone of effective parasite control - even more important than drugs. The most important aspect of management is prompt removal of manure from the environment, before worm larvae can be ingested by horses. There are many other management points to consider, but they are discussed elsewhere. Here are the common drug types used in horses. BENZIMIDAZOLES. A class of compounds called “Benzimidazoles” have been a mainstay of equine parasite control for over 40 years. These chemicals interfere with a worm’s energy metabolism on a cellular level, causing a slower kill of the parasites than the so-called “paralytic compounds”. Familiar examples of benzimidazoles are fenbendazole (Panacur®) and oxibendazole (Anthelcide® EQ). These continue to have good activity against Ascarids, but small strongyles are now mostly resistant to this class.  For this reason, these drugs should probably only be used in young horses. Another class of de-wormer includes pyrantel pamoate and pyrantel tartrate (the familiar trade name Strongid®). These drugs act at the junction between nerve cells and muscle cells, again causing paralysis and rapid kill of worms. Pyrantel does not penetrate the intestinal wall and so will not kill encysted strongyles. There is now significant resistance to pyrantel among strongyles. Pyrantel comes in several forms, a paste, suspension for tube worming, and at low levels in a pellet (continuous wormers like Strongid-C®). Pyrantel at very high dose may have activity against tapeworms. It is generally very safe for all age classes of horse. While continuous wormers have been implicated in resistance, they still may have a niche role in Reinemeyer’s estimation “for selected horses on the farm, for a selected time period, but never for life.” MACROCYCLIC LACTONES (Ivermectin & Moxidectin). Ivermectin has been around for about 30 years and has been our most relied upon wormer, but there is evidence now that certain parasites are developing resistance. Ivermectin and Moxidectin are potent at even low levels. They work by blocking nerve transmission and paralyzing worms. Unlike the other drug classes, macrocyclic lactones also kill external parasites like lice, mites, and larval skin forms involved in summer sores. They kill bots very effectively. Moxidectin is a more recently developed drug, and has the ability to penetrate into the intestinal wall and kill encysted strongyles. It probably is the most effective compound for this purpose.  This drug is not recommended in horses less than 2 years of age, and for smaller equines.  One to two treatments of macrocyclic lactone per year will probably control both large and small strongyles, bots and other important parasites in most horses. PRAZIQUANTEL.  This drug only kills Tapeworms.  It is currently marketed only in combination with either Ivermectin or Moxidectin . Praziquantel is probably also being overused, especially in regions that have very few tapeworms. According to Reinemeyer “Diatomaceous earth and other “natural” products have to date not been shown to effectively kill parasites.” If you rely on these products, you may be putting your horses at risk. CONCLUSION With these basics in mind it may be helpful to consider your own unique circumstance and ask yourself some questions.  What is your current deworming program and how do you evaluate its efficacy?  Have you changed your approach as the industry has become more aware of drug resistance? Have you done all you can do to reduce the number of worms ingested by your horses? What worms are likely to be a problem for your horses, given your geographic region and management? With a stronger understanding of the worms and their life cycles, and the drug used to combat them, you can take a smarter approach to parasite control and help slow the onset of drug resistance while still ensuring the health of your horses. Work with your veterinarian to develop a targeted parasite control plan that is tailor made for your situation. By Douglas O. Thal DVM Dipl. ABVPBoard Certified in Equine PracticeThal Equine LLCOriginally Published in The Horse Magazine April 2014  


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