Ensuring A Healthy Pregnancy for Your Mare

 

Sarah Gold , DVM

Associate Veterinarian, B.W. Furlong & Associates

As foaling season approaches, it is imperative to maintain proper mare management to ensure the birth of a strong, healthy foal. The average gestation length in the mare is 340 days, or approximately 11 months. With the exception of a high-risk mare, maintaining a good plane of nutrition and overall health status sare the major concerns for ensuring a healthy pregnancy.

Your mare should receive inoculatino against Equine Herpes Virus-1 (Rhinopneumonitis), which is a disease that causes abortion in mares. Vaccinations should be performed at 5, 7, and 9 months of gestation ( a vaccination at 3 months is recommended in higher risk mares or farms with a history of herpes virus or abortion). It is imortant to remember that this vaccination program is only one component of the prevention and control of abortion caused by EHV-1 infection, as vaccination provides partial protection against viral shedding and of the disease. Good broodmare management is also an important consideration, i.e. minimizing stress, reducing contact with transient horse population, and good hygiene.

A good deworming program should be in place throughout the pregnancy and should include ivermectin, pyrantel pamoate, and fenbendazole. Although most commercial products are safe to use in pregnant mares, always read the precautions on the package insert of any deworming product and DO NOT use any product containing organic phosphate. The deworming program should be suited to the individual needs of the farm upon which the mare is stabled. Some owners choose to administer ivermectin to the mare on the day of foaling to minimize transmission of infective larvae ti the foal by nursing beginning around day 4 after birth.

Pregnant mares should be kept in good body condition, although not obese, as this has been associated with the birth of weak, small foals. During the first 8 months of pregnancy, nutritional requirements are not affected by pregnancy. Additional maternal nutrition is recommended for months 9, 10, and 11, as 60-65% of fetal groth occurs at this time; the mare's energy requirement increases 10-20% and protein requirements increase 30%. A good rule of thumb is that after month 8, her feed should be increased to 1.5 times maintenance, and after foaling, her feed should be increased to twice maintenance during lactation. Alfalfa hay is a good source of protein for pregnant and lactating mares. Also, as the fetus takes up more room in the abdomen, feeding grain as well as good quality hay high in digestible energy is important. The amount of calcium and phosphorus needs to be considered (as well as the ratio between these two minerals, sa phosphorus content should not exceed calcium content in the feed) to avoid osteochondrosis of the fetus. Alfalfa and other legume hays are substantial sources of these minerals; otherwise it may be necessary to consider supplementation of these minerals in the grain. Finally, fresh clean water and salt licks should be available to the mare at all times. The take home message is to monitor your mare's weight closely and adjust nutritional plane as needed.

Approximately 4 weeks prior to the expected foaling date (10 months of gestation), your mare needs to receive vaccination boosters to ensure adequate antibodies in colostrum for the foal. In this geographic region, the mare should receive vaccinations for Eastern and Western Encephalomyelitis, Rhinopneumonitis (respiratory), Influenza, Tetanus, Rabies, Botulism, West Nile Virus, and Potomac Horse Fever. If your mare has a caslick, this needs to be opened 2-4 weeks prior to birthing, and this can be done at the same time as her pre-foaling vaccinations.

Please do not hesitate to call us to set up a time to discuss any concerns or issues regarding your pregnant mare. This is a good time to discuss any issues concerning pregnant mare management, the birthing process, and immediate aftercare of both mare and foal. Also watch for our popular Mare and Foal Seminar offered in early Spring 2007.

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