How to care for a pregnant mare
A mare's gestation period lasts for over 300 days.


Mares gestate for approximately 345 days, according to TheHorse.com, but equine pregnancy isn’t a year full of fragility. On the contrary, most horses do relatively well when pregnant, and you’ll only need to make a few minor adjustments toward the end of term to have a safe delivery. The fetus doesn’t start to fully develop until the final three months, so the mare is more or less similar to the rest of the herd beforehand. Still, leaving a pregnant horse to fend completely for herself spells disaster for mother and unborn child. Here’s what you need to know about the various aspects of pregnant mare health:


“Healthy mares can continue their original training regimen.”

Physical fitness is important for a healthy pregnancy. Luckily, since most of the physiological changes occur towards the end of term, healthy mares without a history of birth issues can continue their original training regimen. Some can even compete throughout the beginning and middle stages. There is a slight risk that the fetus will damage or rupture the abdominal wall if the exercise is too strenuous, but this is incredibly rare.

That said, Aime Johnson, associate professor at Auburn University College of Veterinary Medicine in Alabama, told TheHorse.com that it’s a good idea curb to physical activity during the first month of pregnancy. This way, you or your veterinarian can spot any signs of current or future health issues.

“Those first 30 days are really critical, so she shouldn’t be doing any high-level exercise, especially in the hot summertime, until that pregnancy is more well-established,” Johnson told the publication.

Training should be scaled back, but not fully eliminated, when the mare’s pregnancy hits the eight-month mark. At this point, the fetus’ development will prevent the mother from performing to her normal abilities and put too much stress on the body. Notably, the growing foal causes the mare’s diaphragm to shift, so she won’t be able to take in as much oxygen as she used to.


Pregnant mares are eating for two, so you must take care of both her nutritional needs and those of the unborn foal. According to Equisearch, foals need lots of proteins, minerals and energy to assist their rapid development. However, the amount of each nutrient you give to the mare is not even across the board. Pregnant horses need 80 percent more calcium and phosphorus, but they only need 42 percent more protein and 28 percent more calcium. Therefore, simply adding more feed results in a nutritional imbalance.

To support a healthy pregnancy, feed your mare a grass hay diet with little to no grain. Look at the origins of the feed and consult with your veterinarian on any nutritional deficiencies. You may also want to add equine supplements to boost specific vitamins and minerals. Even if the feed itself is nutritionally satisfactory, your mare will still need a boost. Finish Line has several daily supplements blended with calcium, something she definitely needs more of. Try our Vitamin B1 Blend, Vitamin C Blend or Thia-Cal.

A horse in a stable.


Keep your mare up to date on her vaccines, as many of these carry over to the fetus. The American Association of Equine Practitioners recommended mares be immunized at the beginning of a pregnancy for the following conditions:

  • Influenza.
  • Tetanus.
  • West Nile virus.
  • Eastern and Western encephalomyelitis.

At five, seven and nine months, pregnant mares should be immunized against equine rhinopneumonitis. Finally, the mare should receive a booster of the first set of vaccines about a month before she’s due. These shots increase the amount of antibodies in the initial milk she produces, protecting the foal from serious diseases.

Your mare might also benefit from additional vaccines depending on your location. Consult your veterinarian for advice on protecting the mother and foal against regional diseases.

Finally, make sure your horse is dewormed so parasites don’t transfer during pregnancy, birth or nursing. Most deworming medications are safe for pregnant mares, but contact your veterinarian first to choose the right one and set up a schedule.

The birth

Keep your mare at home during the last two to three weeks of pregnancy, as the stress of traveling can trigger labor. If you must move her, make sure she has plenty of space in the trailer. Before she’s due, make sure her vulva hasn’t been sewn shut. Otherwise, the resulting damage can prevent her from foaling ever again.

Observe the mare’s udders during the last few weeks, as early leaking could be a sign of infection. When the horse is close to delivering, check on her every hour. If she’s lying down, she’s ready to give birth. Make sure she does so inside if the weather is cold – foals can easily contract hypothermia.

Finally, start timing how long the mare is in labor. If the process lasts for more than 20 minutes, call a veterinarian.



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