Broodmares Require Fall And Wintertime Attention

By Frank J. Buchman
Foals are weaned and broodmares are generally out in the pasture waiting with their owners for new babies come spring.
While daily feeding and observation are customary, most owners often become relaxed in broodmare attention during the fall and winter.
Yet, additional management has been suggested by Dr. Laurie Lawrence, animal scientist specializing in equine reproduction.
“It’s a good idea to check broodmares by ultrasound or palpation to confirm that their pregnancy is progressing normally,” Lawrence recommended.
Often, a horse breeder doesn’t know a mare lost her pregnancy until she doesn’t foal in the spring.
“Unfortunately, about 15 percent of broodmares safe in foal earlier lose their pregnancies each fall,” Lawrence said. “This is too late in the breeding season to determine the cause of the lost pregnancy and rebreed the mare. As a result, the owner loses an entire year.”
Still, there are a number of things broodmare owners should do for mares that are safe in foal, Lawrence indicated.
Many mares drop in body condition each fall due to decreased good quality pasture and the onset of cold weather.
“Demands on the mare by the fetus won’t require increased feed until the last one-third of pregnancy,” Lawrence explained. “However, the energy required to keep warm will increase.”
A mare in good condition will provide adequate milk for her foal and breed back quicker than a thin mare.
“Mares should have a level back and slight fat cover over the ribs,” Lawrence described. “Fat should be evident along each side of the mare’s neck and behind her shoulders.”
However, a mare should not be overweight. “Fat mares tend to produce less milk than moderately fleshy mares, and their foals gain less weight,” Lawrence pointed out.
A healthy mare in good flesh will gain 9-12 percent of her original body weight during pregnancy. For example, a 1,100-pound mare should gain roughly 100-130 pounds during the course of gestation.
“She should gain two-thirds of the weight in the final three months before foaling, often requiring supplemental feed,” Lawrence said.
The American Association of Equine Practitioners recommends fecal egg count testing as a basis for parasite control. “In general, a minimum of spring and fall deworming treatments should be considered for all pregnant mares,” Lawrence advised.
Four to six weeks prior to the expected foaling date, mares should be vaccinated to prevent diseases. Recommended vaccinations include: tetanus, Eastern and Western Equine encephalomyelitis (sleeping sickness), West Nile virus, Rabies, Equine influenza and equine herpes.
“This benefits both mare and foal as the mare passes disease antibodies through her colostrum to the newborn,” Lawrence explained.
Mid-to-late pregnancy mares should receive rhinopneumonitis (rhino) vaccinations. “Typically pregnant mares are vaccinated during their fifth, seventh and ninth months of pregnancy for rhino abortion protection,” Lawrence said. An alternate program is to vaccinate for rhino every other month once the mare becomes pregnant.
Other common vaccinations that might be considered include Strangles, Potomac horse fever, and botulism.
Lights can be used to hasten transition to estrus in open mares and shorten the gestation period in bred mares. “A bright lighting program should start in December for at least 16 hours daily,” Lawrence said. “This may cause mares to shed hair early requiring blanketing during cold conditions.”
If a mare is to go across state lines for breeding or rebreeding, a health certificate is typically required. “Early winter is a good time to draw blood for equine infectious anemia testing,” Lawrence suggested.
Fescue pastures and hay can be a problem for broodmares. Fescue is sometimes infected with an endophyte fungus producing a mycotoxin causing prolonged gestation, foaling problems and low milk production.
“Remove pregnant mares from fescue pastures 60-90 days prior to their anticipated foaling date,” Lawrence recommended. “The medication Domperidone can help counteract effects of fescue toxicosis during the last 25-30 days prior to foaling.”
However, an infected mare, even following preventive treatment, still might not produce adequate colostrum. “It’s always a good idea to have some frozen colostrum on hand for the newborn foal,” Lawrence said.
Now is a good time to inventory foaling and breeding related supplies to ensure they’re available when the mare foals.
“Evaluate foaling areas to make sure there are no hazards for the mare or newborn foal,” Lawrence recommended. “Develop an emergency plan with your veterinarian for your mares, and place emergency numbers near the phone.”

Broodmares require more attention during fall and winter than most horse breeders often think they do.