What to Expect When Your Mare is Expecting

By Anna O'Brien, DVM on Jun. 14, 2013

An equine pregnancy lasts eleven months, which means there’s almost a full year to get excited and be as prepared as you can for the arrival of a foal. Let’s take a closer look at what to expect when your mare is expecting.

The majority of fetal growth occurs in the last trimester of pregnancy. For the mare, this means her nutritional requirements will increase and she will begin to actually “look” pregnant starting around her seventh or eighth month of pregnancy. Every mare is different, so be sure to talk regularly with your veterinarian about your mare’s specific dietary needs.

Regular exercise and routine hoof maintenance should be kept up during pregnancy, and the mare should receive booster vaccines for a contagious virus called equine herpesvirus, which can cause abortions if contracted by the mare. Mares in early pregnancy can still be ridden, but riding should stop when she is in her third trimester. However, she should still be allowed out on pasture to graze.

One vital aspect to a pregnant mare’s health is the type of grass she is grazing. Pregnant mares in their third trimester should not graze in pastures containing fescue grass. Some types of fescue are infected with a certain fungus that causes a variety of very serious complications, such as prolonged gestation, agalactia (meaning the mare cannot produce milk for her foal), and premature separation of the placenta, a term called “red bag,” which causes oxygen deprivation for the foal.

As the anticipated date of foaling nears, the mare will begin to “bag up,” meaning she will begin producing milk and her udder will swell. Waxy plugs will begin to form on her teats and some mares will even begin to drip some milk. There are commercial kits available for purchase that will test a mare’s milk for levels of calcium. These numbers are fairly good predictors of when the mare will foal.

As the mare gets close to foaling, make sure you have the necessary supplies. A properly equipped basic foaling kit should include, but is not limited to, the following items:

veterinarian’s phone number

flashlight and batteries

plenty of clean, cotton towels

tail wrap

iodine

Ivory soap

clean bucket for water

KY jelly

gloves (preferably long-sleeved OB gloves)

large trash bags

thermometer

stethoscope

In the hours before actual foaling occurs, the mare will exhibit certain behavioral patterns. She will become restless, look at her flank, get up and down repeatedly, and may pass small amounts of manure. These clinical signs are similar to when a horse has colic. For a mare about to give birth, these signs are produced because of the start of uterine contractions.

The process of foaling proceeds in three stages. Becoming familiar with each stage will help you monitor progress and know when to call your vet for help. Stage 1 occurs when the mare’s water breaks. This signifies the rupture of fetal fluids called allantoic fluid, which surrounds the fetus in the placenta.

Almost immediately after Stage 1, the mare will begin having very strong abdominal contractions. This is the beginning of Stage 2. During Stage 2, the foal has moved into the birth canal and is ready to be delivered. Normally, the foal is positioned with the front feet first, followed closely by the nose.

Ideally, when in proper alignment, the first thing an assistant should see is two front feet with the soles facing downward, one hoof slightly ahead of the other, followed closely by a nose. If any of this is not seen, the vet should be called immediately, as this indicates the foal is in an incorrect position which may lead to problems with delivery.

Stage 2 happens quickly. A foal’s birth is often described as “explosive” because it happens so fast, usually less than twenty minutes. Most mares will lie on their side when pushing, and then the strong contractions stop after the foal’s hips are out. Stage 2 is finished when the foal is completely delivered. If Stage 2 takes longer than roughly forty minutes, or if it appears no progress has been made at any point during this stage, the vet should be called.

Within an hour of birth, the foal should be standing or making strong efforts to stand. The mare will normally lick and nuzzle the foal to dry him off and encourage him to get up and start nursing. Stage 3, the final stage, occurs when the mare passes the placenta. This normally occurs within a half hour of birth, and should occur no later than three hours after the foal is born.

The mare will have mild contractions during expulsion of the placenta. As the mare is passing her placenta, do not try to help by pulling it out. This may result in tearing it, leaving a piece still inside the uterus, which can make the mare very sick. If you are worried about the mare stepping on the placenta, you can tie it in a knot above her hocks. Once the placenta is passed, place it in a trash bag and keep it in the refrigerator for the vet to examine when she arrives to check on the newborn foal.

If the placenta is not passed within three hours, call the veterinarian. Retained placentas in mares are very serious, as they can cause life-threatening infections of the uterus, which can result in blood infections and severe hoof inflammation called laminitis.

Once the foal has arrived, make sure his nose is free from any membranes so that he can easily breathe. The umbilical cord usually breaks on its own and within a few hours of birth, should be dipped with dilute iodine in order to keep it clean. The umbilical area is a common area of infection in foals.

Your veterinarian should come out within about 24 hours of birth to examine the foal and mare. In the meantime, during the foal’s first few hours, make sure he is nursing. It is imperative for newborn foals to consume adequate amounts of the mare’s first milk, called colostrum. This milk is filled with antibodies that the foal needs for immune protection.

Some mares are not able to produce colostrum with enough antibodies. To determine if your foal has consumed enough colostrum for sufficient immune protection, your vet can draw a blood sample from the foal and measure antibody levels. If these levels are low, the foal can receive a plasma transfusion to bolster his immune system during the first few weeks. As the foal grows, he will then start producing his own antibodies.

Once your foal and mare have received a check of health from the vet, you can relax and enjoy the newborn! Foals grow quickly and are a joy to watch as they learn to run on their long legs and explore their environment. Careful monitoring will help ensure your foal has a strong start at life.