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 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.


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.


  • 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.


Waxing of Teats – Often (but not always) seen just prior to foaling.

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.


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.

Attended foaling by a veterinarian can ensure success, particularly in cases of a difficult or delayed foaling (dystocia).

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.


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).


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.

Complete & Healthy Equine Placenta

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.


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.

Post-Partum Exam of Mare and Newborn Foal

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. ABVP
Board Certified in Equine Practice
Thal Equine LLC
Last Updated August 2011 

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