Broodmare Management

 

Rachel Gardner, DVM, DACVIM
Internal Medicine Specialist, B.W. Furlong & Associates

The average gestation length of the mare is 340 days. This gives you about 11 months to monitor the development of the foal and the health and condition of your mare. Below are some general guidelines to help ensure a healthy pregnancy in your broodmare.

Vaccinations

Rhinopneumonitis is the leading cause of infectious abortion in mares. It is caused by Equine Herpes Virus type 1. It is generally recommended to vaccinate your mare against Rhinopneumonitis at months 5,7, and 9 of pregnancy. On endemic farms or farms with heavy traffic of horses on and off the farm, you may want to begin the vaccinations at month 3.

Pre-foaling vaccinations should be given at month 10 of gestation. This allows the mare time to develop antibodies to be delivered in high concentration in the colostrum. Pre-foaling vaccinations should include: eastern and western encephalitis, Rhinopneumonitis (respiratory form), influenza, tetanus, rabies, botulism, potomac horse fever, and West Nile Virus.
Also, if your mare ill be moved to another location to foal, we recommend moving the mare at least one month before the expected foaling date. This new location is likely to have different environmental pathogens, and the mare needs time to develop antibodies to these new pathogens so she can pass the protection on through the colostrum.

Caslicks

Your mare should be evaluated for a caslick at month 10 during the visit for pre-foaling vaccinations. Caslick refers to the surgical procedure of suturing a portion of the vulva lips together as an added defense against contaminants gaining access to the mare’s reproductive tract. This will need to be opened prior to foaling too prevent injury in the mare during parturition.

Nutrition

No additional nutrients are needed to sustain fetal growth during the first 8 months of pregnancy. During this time, the pregnant mare can remain on her normal plane of nutrition as long as she maintains good body condition. Fetal growth accelerates rapidly during the last three months of pregnancy as does the mare’s nutritional requirements. During the last trimester, the mare’s energy needs increase 10-20% and protein requirements increase 30%. Supplementing with alfalfa hay at this time is a good idea as alfalfa is higher in energy and protein than grass hay and is also a good source of calcium.

Lactation produces an even greater demand on the mare. During the first 3 months of gestation, the mare produces 3% of her body weight in milk each day. Because of this, her energy requirements increase 80% and her protein needs increase 120%. Depending on the condition of the mare at foaling, these needs can generally be met with a grain of at least 12% and good quality hay. Again, alfalfa is a good supplement if needed.

The most important thing is to monitor your mare’s weight closely and adjust the nutritional plane as needed.

< Return to News & Articles