Five Management Factors for Pregnant Mares

So your prize mare is bred and there is nothing to do but wait a year until the foal of your dreams is born. Wrong! Nutrition, exercise, parasite load, vaccinations, and pregnancy monitoring are a handful of factors that, when managed carefully, can improve your chances for a healthy pregnancy and equally healthy newborn.

"Throughout gestation, the pregnant mare should be maintained on a balanced ration that will allow her to say healthy and active," says Dr. Deborah Rowley, veterinarian at the University of Illinois College of Veterinary Medicine Teaching Hospital. "The average mare will consume about 1.5% to 2.0% of her body weight each day in quality feed. When quality feed is provided, additional vitamins and feed additives are usually not necessary."

Climate exposure can influence the nutritional requirements. The weather pregnant mares can withstand depends upon what the mare is acclimated to. "Any time an animal reaches the extreme of its thermal neutral zone, excessive energy is required to increase or decrease the animal's body temperature. If climate control is not an option, make sure you are meeting additional nutritional needs of the pregnant mare during extreme weather," explains Dr. Rowley.

"Excessive weight gain or loss should be avoided," Rowley adds. "Though you should be able to palpate the ribs, they should not be visible on a well-conditioned horse." Exercise can keep the excess weight gain down. "Moderate riding and work is usually safe up to 5 months gestation; moderate activity and free exercise are encouraged throughout pregnancy," says Dr. Rowley.

Protecting the mare from parasites protects the fetus. Age, housing, and exposure all contribute to the continual health threat of parasites. Always read labels and check with your veterinarian before deworming. Certain products are not safe for the various stages of pregnancy. Dr. Rowley has some additional tips about controlling mare exposure to parasites.

* All horses on the farm should be included on a scheduled deworming program.
* Pasture animals of similar age and uses together. Younger horses can carry large parasite burdens, populating pastures with parasites passed through fecal material.
* Avoid overstocking and feeding on the ground.
* Transient and newly acquired horses should be dewormed and isolated 1 to 2 weeks before turned out with resident horses.
* Have laboratory examinations of farm samples routinely examined by your veterinarian.
* Dose dewormers according to dosage recommendations.

Along with a scheduled deworming program, a scheduled vaccination program coordinated by a veterinarian is important for your farm. "Devise a vaccination program specific for your farm needs: locality, horse use, horse exposure, ages. It is especially important to immunize pregnant mares against Rhinopneumonitus at 5, 7, and 9 months and to administer pre-foaling immunizations about 3 to 4 weeks before her due date," Dr. Rowley says.

Pregnancies can be monitored via ultra-sound or manually by a veterinarian. Mares who have had problems with pregnancy and foaling are more likely to have problems again. High-risk pregnancies can be caused by twinning, poor vulvar conformation, colic, lameness, and exposure to toxic substances. "Mares exposed and infected with equine herpes virus accounts for the highest proportion of diagnosed causes of infectious abortion in the mare," informs Dr. Rowley.

Remember to be aware and prudently manage these five factors: nutrition, exercise, parasite load, vaccinations, and pregnancy monitoring. And if problems or questions arise be sure to consult your equine veterinarian.

By Sarah Probst, Information Specialist
University of Illinois - College of Veterinary Medicine