Pregnancy in Horses

Pregnant mare

What to Expect When Your Horse Is Expecting

Are you eagerly awaiting the addition of a new foal to your stable? Familiarizing yourself with equine pregnancy basics can help you keep your mare healthy throughout the entire pregnancy.

The First 30 Days

An ultrasound examination can usually show evidence of pregnancy about two weeks after breeding or insemination. Pregnancy can also be confirmed by trans-rectal palpation performed at approximately 30 days. During trans-rectal palpation, your equine veterinarian inserts his or her arm into your horse's rectum and feels the cervix, ovaries, and uterus.

Keeping your horse healthy during the first month is particularly important, due to the 10 to 15 percent chance of pregnancy loss, according to the American Association of Equine Practitioners. Vigorous exercise, illness, stress, and uterine infections can cause spontaneous abortions (miscarriages). It's a good idea to schedule another ultrasound a month or two after the first one to confirm that your mare is still pregnant.

Is Your Horse Eating for Two?

Most horses can continue their usual diets during the first seven or eight months of pregnancy and only require minor feeding changes during the last three or four months. During those last months, you may need to increase feed amounts slightly and choose high-quality feeds, forage, and grains. Commercial feeds intended for pregnant mares can simplify the feeding process.

Although your horse may need a little more hay or forage, be careful not to overfeed. Overfeeding can cause fat deposits that narrow the birth canal or lead to laminitis, Aime Johnson, DVM, associate professor of theriogenology at Auburn University of Veterinary Medicine told Horse Magazine. Laminitis is a hoof disease that can be fatal in some cases.

What About Exercise?

Most mares don't need exercise restrictions after the first 30 days. You'll probably be able to ride your horse up until the eighth month of pregnancy. As the fetus grows, it may press against the horse's lungs, making breathing more challenging. Vigorous exercise may not be recommended during the final months of pregnancy, but your horse still needs to stay active. Hand-walking can help her meet her exercise needs.

Protecting the Mare's Health

These steps will help keep your horse healthy and reduce the risk of embryo resorption or abortion:

  • Provide access to an ample supply of clean water. Stagnant water may contain bacteria that could sicken the mare and the fetus.
  • House competition horses or other horses that travel often in another area of the stable. Separating these horses will prevent the spread of disease.
  • Ask your equine vet to update your mare's vaccinations and make deworming recommendations. These simple health measures protect the mare and the foal.
  • Schedule regular sessions with the farrier to prevent overgrowth of the hooves. Even if your horse isn't particularly active, regular trimming may still be needed.
  • Look for signs that foaling is approaching, including a swollen abdomen and enlarged udder. These signs usually occur about a month before delivery. If you see dried secretions on the udder, a few drops of milk, or notice that your horse's tail is higher than normal, birth may occur in a day or two.

Know When to Call the Veterinarian

After nearly a year of pregnancy, labor, and delivery proceed fairly quickly. In the first stage, your horse may seem agitated and struggle to find a comfortable position. During the second stage, the mare's water breaks, signaling that birth is imminent. Foals are usually born about 30 minutes after the water breaks.

The amniotic fluid should be clear yellow. If it's brown, let your veterinarian know, as this could mean that the foal has inhaled meconium. Meconium is the first stool produced by the foal. If it's inhaled, pneumonia can threaten the newborn's health.

Call the equine vet if stage one takes more than two hours, the placenta isn't expelled within an hour of the birth, or if you don't see any signs of an emerging foal after 15 minutes during stage two. Normally, you should see two hooves and the head. If you see any other combination or notice that a hoof is protruding from the mare's anus, let the vet know immediately.

Is your horse pregnant? Regular veterinary care can increase the chances of a healthy pregnancy. Contact our office to schedule an appointment for your horse.


American Association of Equine Practitioners: Expectant Mare: Assuring the Health and Well-Being of the Pregnant Mare

The Horse: Managing Pregnant Mares, 5/15/20

EquiMed: Horse Gestation Timeline, 5/717

University of Minnesota Extension: Caring for Your Mare During Breeding and Foaling


Find us on the map

Office Hours

Our Regular Schedule


8:00 am-5:00 pm


8:00 am-5:00 pm


8:00 am-5:00 pm


8:00 am-5:00 pm


8:00 am-5:00 pm


9:00 am-2:00 pm




Read What Our Clients Say

  • "Kath, thank you so much for being Greyson's vet, your gentle hand, compassion and great skill made all the difference for my buddy."
    --Deirdre Dekking, Portland
  • "Dr. Mertens is a very friendly, knowledgeable equine veterinarian (and a friend to the rest of the farmyard, including the chickens!). Always up to date on the latest in equine health, and even though Mertens Mammals is a small clinic giving you the personable experience, Dr. Mertens also has equipment for more advanced diagnostics and procedures!"
    —Ari Gordon, Boring
  • "I have been a client of Mertens Mammals for 10 years. Kath (Dr. Mertens) is the most kind, thoughtful and caring Vet I have ever had for my animals. I have 3 horses: my Appy "Breeze" who turns 30 this year, my Paint " Rocket " 14 and my other Paint "Fergie " 3 are all under Kath's care. I also had a dog "Cowboy" who I lost to cancer last July. Kath took care of him also. Dr.Mertens came out on Mother's Day about 7 years ago to treat Breeze for a cut above her right eye. After a few weeks of recovery we were happy to not have a huge scar. Kath also spent 2 hours with me 3 years ago when Rocket had a small case of colic. (Thank God). I couldn't ask for a better person to take care of my girls. Kath always calls to check in on the patients. When people ask who I use for my veterinary needs for my horses, I'm always proud to refer them to Mertens Mammals. I am so thankful for an honest and caring Vet. Thank you, Kath!"
    --Michelle Schatz, Portland
  • "I got looking at Sassy’s records and it will be 6 years in July when you first met Sassy—I feel so fortunate that you became her vet and have looked after her all these years. You are such a wonderful and caring doc and I know you always have Sassy’s best interests at heart. I also know I can always rely on you to help me or Sassy when needed. Thanks for all you do for both of us—will keep you posted on Sassy.”"
    —Judy Becker, Eagle Creek
  • "My horse, Pester, would have lost her eye had it not been for the great care and dedication by Mertens Mammals. They are truly there for you any time you need them. I could go on and on. Kath Mertens has been so good to us!"
    --Troy and Wendy Mohr, Estacada
  • "She has always been there for us. She is forever in my thoughts as the best vet. She saved our hours old filly from certain death. She knew exactly what to do in an instant after just seconds in seeing her. We are forever in your debt...thank you!"
    Barbara T.
  • "Thank you Dr Mertens for such a thoughtful and careful job with our sweet Daisy the Donkey this morning! She is well on her way to health again after that abscess!"
    Suzi C.