Management of Pregnant Mares

Management of your pregnant mare

The goal of any equine breeder is to keep your mare healthy throughout pregnancy and to have a normal, healthy, full-term foal as the end result.  There are several things to remember during the gestation period that are essential in keeping both mama and growing baby healthy.

First and foremost is nutrition for the pregnant mare.   It is important for the health of the mare and growth and vigor of the fetus for the mare to have not only and adequate calorie intake but also the proper amount of vitamins and minerals.  A mare should receive a diet of about 8% crude protein during the first eight months of pregnancy and then be bumped up to around 10-12% in the remaining  three months.  She should receive a general mineral supplement but you should pay special attention to the amount of calcium and phosphorus the mare is getting.  Mares should receive calcium at a rate of 0.2% of diet for maintenance and early pregnancy and 0.4% for late gestation.  To maintain proper phosphorus:calcium ratios for bone health, phosphorus levels should not exceed calcium levels in any stage of life, pregnant or not, but this is especially critical in late gestation.  Because legume hays such as alfalfa are high in both calcium and protein, feeding these in late gestation may eliminate the need for calcium and protein supplementation in the diet but you would want to have your hay tested to determine exactly how much of each the horse is getting.

Proper deworming and vaccinations are also very important in the health of both the mare and the fetus.  Internal parasite control relies on a combination of pasture and grazing management, manure disposal and strategic use of dewormers.   Most modern dewormers are safe for use in pregnant mares, but always check the label first and consult a veterinarian.  

There are also certain core vaccines that are recommended for the pregnant mare.  These vaccines not only protect mom during pregnancy but also offer protection to the baby through the colostrum while its immune system is still developing.  Below is a chart of the recommended vaccines and when to administer them:

Vaccine	Schedule for Broodmare
Eastern/Western Encephalomyelitis	Every 6 months, boost 30-45 days before foaling date
Tetanus	Annually, boost 30-45 days before foaling date
Rhinoneumonitis	Every 3 months, boost 30-45 days before foaling date
Influenza	Every 3 months, boost 30-45 days before foaling date
Rabies	Annually, boost 30-45 days before foaling date
Potomac Horse Fever	Not routine in this area, if traveling check with you Veterinarian
Strangles (intranasal)	Ask your Veterinarian
Pneumabort-K	At 3rd, 5th 7th and 9th months of pregnancy
Influenza (intranasal)	Every 3 months, boost 30-45 days before foaling date
EPM	Ask your Veterinarian
West Nile	If Open: Initially 2 vaccines 3-6 weeks apart, then every 6 months. If in Foal: THIS VACCINE IS NOT LABELED FOR USE IN PREGNANT MARES

** Each horse should be evaluated based upon his/her use and potential exposure to other horses and wildlife. All pregnant broodmares should be booster-vaccinated at approximately 10 months of pregnancy to insure colostral immunity. They should also receive pneumabort-k vaccines at months: 3,5,7 and 9 months of pregnancy. There is also a new intranasal influenza vaccine available. This can be given in conjunction with the intra-muscular version.

Preparing for a new baby on the farm is exciting but there are lots of important details to keep in mind to ensure the arrival of a healthy, full term foal.  Consult your veterinarian to tailor a program that meets the needs of your mares and your local extension agent with any questions you may have about care of a pregnant mare.  

Adapted From:

1.       Scott Madill, DVM, College of Veterinary Medicine, University of Minnesota. Care of the Broodmare. University of Minnesota Extension Service. 2007. Available at: http://www.extension.umn.edu/distribution/livestocksystems/DI8462.pdf. Accessed: October 10, 2011.

2.       Kim Marie labak,  Veterinary Extension/Office of Public Engagement, University of Illinois College of Veterinary Medicine. Management of Pregnant Mares. 2005. Available at: http://www.thehorse.com/articles/15068/management-of-pregnant-mares

3.       Southern Pines Equine Associates P.L.L.C.- http://www.spequine.com/horse_health.htm