Broodmare Care Schedule: Winter Health Checks

Broodmare Care Schedule: Winter Health Checks

Double-check your broodmares in early winter for the health and safety of mares and their foals.

fall broodmares and foals (Credit: Kathleen Nicholson)

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Now that cold weather has moved in, most broodmares are out to pasture, gestating until their expected foaling dates next spring. It’s a good idea this time of year to recheck all of your broodmares by ultrasound or palpation to confirm that their pregnancy is progressing normally. 

Too often, a mare owner doesn’t know a mare lost her pregnancy until she doesn’t foal in the spring. Unfortunately, each year, up to 15 percent of broodmares that were checked safe in foal at 45-60 days lose their pregnancies by late fall. This is often so late in the breeding season that there is not sufficient time for a veterinarian to determine the cause of the lost pregnancy, treat and correct the problem, and rebreed the mare. As a result, the owner loses an entire year.

There are a number of things you can do to protect your investment and improve the odds of producing a healthy foal next spring. 

Broodmare Body Condition Score

Many mares drop in body condition at the start of fall and winter, because of decreased availability of good pasture and the onset of cold weather. The demands on the mare by the fetus won’t require an increase in feed until the last one-third of pregnancy, but the energy required to keep warm will increase. 

  • A mare in moderate to fleshy condition will be better prepared to provide adequate milk for her growing foal and will breed back quicker than a thin mare. 
  • A mare should have at least a body condition score of 5. She should have a level back and slight fat cover over the ribs, and fat should be evident along the sides of her neck and behind her shoulder. (Learn more about body condition scores.)
  • A mare should not be rolling fat, because fat mares tend to produce less milk than moderately fleshy mares, and their foals gain less weight. 
  • In the last trimester, a mare’s nutritional requirements accelerate, as does the unborn foal’s growth. Her feed ration should increase accordingly. 
  • A healthy mare in good flesh will gain 9-12 percent of her original body weight during pregnancy. For example, an 1,100-pound mare should gain roughly 100-130 pounds during the course of her pregnancy. She should gain roughly two-thirds of the weight in the final three months prior to foaling.

Vaccinating and Deworming Schedule for Broodmares

Once your mare is in good flesh, check her vaccination and deworming schedule

  • Deworm: The American Association of Equine Practitioners recommends fecal egg count testing as a basis for parasite control. Consideration should also be given with respect to the grazing seasons in your climate. Your veterinarian can help you design a deworming program for your broodmares. In general, a minimum of spring and fall treatments should be considered for all of your pregnant mares.

  • Four to six weeks prior to the expected foaling date: Mares should be vaccinated for tetanus, Eastern and Western Equine encephalomyelitis (sleeping sickness) West Nile virus, Rabies, Equine influenza and equine herpes virus This not only benefits the mare but also the foal, as the mare will pass antibodies to these diseases through her colostrum to the newborn.

  • Mid-to-late pregnancy: Pregnant mares should receive rhinopneumonitis (EHV-1) vaccinations. A typical rhino vaccination schedule is to vaccinate pregnant mares during their fifth, seventh and ninth months of pregnancy with a EHV-1 vaccine that is labeled for abortion protection due to EHV-1. An alternate program is to vaccinate every other month once the mare becomes pregnant. 

  • Other common vaccinations that might be necessary: Strangles, Potomac horse fever, and botulism. Contact your local veterinarian about a good vaccination program for your area of the country. 

Using Lights to Shorten Broodmare Gestation 

If you want to hasten the transition to estrus in open mares or slightly shorten the gestation period in bred mares, start lighting programs on or before December 1. 

  • The lights should be bright enough so that you can easily read a newspaper in the stall. 
  • Lights should provide at least 16 hours of total daylight. 
  • Mares will begin to shed their hair after about 90 days under lights. 
  • Be prepared to blanket your mare if you live in a cold climate.

Other Broodmare Health Concerns

Transporting Broodmares

  • If your mare will be on her way to a broodmare farm or across state lines to be rebred, now is a good time to ask your veterinarian to draw blood for a Coggins test for equine infectious anemia. 
  • A negative Coggins test and current health certificate are required by most states and broodmare farms. 
  • Too often, mare owners are not aware of this requirement and learn of it only when they are ready to ship their mares. 

Broodmares on Fescue Pastures

Make decisions now regarding management of your mares if they are on tall fescue pasture or are being fed fescue hay. Fescue is a common pasture forage in most parts of the country and is relatively harmless to adult horses. However, keep these considerations in mind: 

  • Fescue is frequently infected with an endophyte fungus (Festuca arundinacea) which produces a mycotoxin that can cause prolonged gestation, lack of milk production and foaling problems in pregnant mares. 
  • Remove pregnant mares from fescue pastures 60-90 days prior to their anticipated foaling date. If removing the mares isn’t possible, provide them with plenty of good-quality fescue hay the last few months of pregnancy and consider administering domperidone daily. 
  • Domperidone helps counteract the effects of fescue toxicosis during the last 25-30 days prior to foaling. 
  • Because an affected mare, even following preventive treatment, might not produce adequate amounts of colostrum, it’s a good idea to have some frozen colostrum on hand for the newborn foal. 
  • Talk to your veterinarian if your mare will be on fescue pasture during the last trimester of pregnancy.

Preparing for Foaling: Readying Your Plan and Supplies

Finally, now is a good time to inventory foaling- and breeding-related supplies and equipment to ensure that they are available when your mare foals: 

  • Develop an emergency plan with your veterinarian for your foaling mares. (See this plan and supply checklist.)
  • Review the three stages of the normal foaling process to ensure that you are able to recognize problems early enough to get help. 
  • Place emergency phone numbers near the phone in your barn or on your cell phone, and evaluate foaling areas to make sure there are no hazards that might injure the mare or newborn foal.