A Horse's Gestation and Foaling

The typical length of a mare's gestation is 340 days plus/minus 20 days. Pregnancies lasting longer than 360 days are considered prolonged and the foal may be "over developed." However, there's a record pregnancy length of 419 days that resulted in a healthy foal.

Mares should receive their normal diet during the first two trimesters of pregnancy. During the final months, the mare's feed should be slowly increased to provide the nutrition her rapidly growing foal is taking out of her body. A high-quality mare and foal feed is an excellent source of nutrition as well as green, leafy hay and a vitamin supplement. Fresh, clean water should be available at all times. The mare will need to drink large quantities of water to produce milk to feed her foal. Many mares will easily drink more than 30 gallons of water everyday in the first few weeks their foals are nursing.

Maintaining a mare's fitness level during pregnancy can make delivering the foal much easier for her. Mares should continue being ridden and worked normally until the last few months of their pregnancy. At that time the mare starts to become heavy with foal and her energy levels may begin to decrease. This is a good time to allow the mare to spend her days in the pasture where she can move freely and at the slow speed she's likely to favor. Other exercises that are good for the late-term mare include hand walking, lunging and ponying.

While you can continue to ride a mare up until the time she foals, you may find that your saddle no longer fits your mare properly and that she shows little interest in moving any faster than a trot. This is an excellent time to work on riding bareback.

Photo Courtesy: kcblanchett

Preparing for the birth of your foal is an important step to start his life out right. Keep your veterinarian's phone number handy so you can call him or her in case of an emergency and because they'll need to come out and administer the foal's first shots if you're unable to. Oftentimes, the newborn foal has trouble passing his first bowel movement and will need an enema. Your vet may also want to inspect the placenta to make sure it has been completely passed. If any of the placenta remains inside the mare she can suffer from placental founder.

When you discover that your mare is starting to develop an udder you will need to purchase some straw bales to bed her stall with. Start by mixing a little straw in with her regular bedding every time you clean her stall, adding more straw every day. Your mare will probably consider the straw a snack at first, but she will become used to it and eventually stop eating so much of it. Straw is the ideal bedding for a mare to foal in because it won't stick to the foal as much as other types of bedding. Bales of shavings are also important to have on hand for when the foal starts trying to stand. Straw is extremely slick footing and makes it difficult for the foal to stay on it's feet, so you'll want to start dumping shavings in the stall when you notice the foal trying to get up.

Ideally, your mare will foal out in a grassy pasture. However, not everyone has that luxury. If you do, make sure your fences are in good repair and foal-safe. Barbwire fencing is not appropriate for foals, or any horses for that matter. Many horses die each year from injuries sustained when they became tangled in barbwire. I have personally seen a gelding who became tangled in barbwire and ripped 1/3 of his front hoof off and had an extremely deep laceration on his hind leg. He lived, but it cost his owner well over $3000 in vet bills. It would have cost less than $300 to replace the fence.

Photo Courtesy: pickle

Approximately 4-6 weeks before a mare foals her udders will start to develop and produce colostrum. Colostrum is the highly nutritious first milk that's packed with the mare's antibodies to all of the illnesses she's encountered or been vaccinated for. It's absolutely essential that the foal is able to get the colostrum because his body has no immunities to any diseases and will not start developing antibodies until 6 months of age.

Keep track of the color of your mare's milk and watch for the development of wax on the end of the teats. As your mare gets closer to the end of her pregnancy her milk will have larger and larger amounts of calcium in it, turning it from a clear, watery liquid to a white and slightly thicker milk. Wax starts forming in the last few weeks, building up more quickly as the mare comes closer to foaling. Strip the wax off of one teat every day and note how quickly it reforms. When I took breeding classes we were taught to: StRip the Right, Leave the Left.

If you want to test the calcium levels you can buy a calcium test kit from a pool store. Collect some milk in a container and dilute it with 5 parts water. Use a test strip and record the results. Once the mare starts having high results with 5 parts water you should start diluting the milk with 10 parts water. When those results become high you should start keeping a close eye on your mare for other signs of foaling.

Photo Courtesy: taliesin

Weeks or hours before the mare gives birth the foal will rotate and get into the proper position for delivery. This makes a noticeable change in the mare's body. You'll notice that the mare suddenly has the upper part of her ribs showing near the spine and her spine may become more prominent as well. This is because the skin is stretched tight over those areas from the weight of the foal. She'll also look like the foal's weight is settled down and back towards her hind end versus her previous appearance which was starting to look overweight.

The muscles around the croup will relax to allow the sacral vertebrae to lift as the foal is pushed out. This results in what I fondly call "jello butt" because the muscles are so soft that your finger will sink in significantly when you push on them.

The mare's vulva will also start to length as the final days go by. It will be much longer right before the foal is born.

Photo Courtesy: taliesin

A mare in early labor might not show any signs, especially if she's had more than one foal. However, the following symptoms are signs of impending birth (the first signs are also common symptoms of colic):

Sweating

Nervousness

Biting at sides

Rolling more than usual

Getting up and down

Dripping milk

Contractions

Discharge from the vulva

Photo Courtesy: pambenn
I do have pictures of a mare foaling, but some people consider them "graphic" so I haven't put any up here.