Feed Requirements Depend on the Physiological Status of Your Mare

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The relationship between nutrition and reproduction has been one of extreme interest to the animal science community.

The various gestational stages of the mare necessitate different nutritional requirements. What she eats prior to breeding may not be as important as what she eats when lactating (just an example). It is important to know and understand the differences in physiological status and how to feed accordingly; it is essential in providing proper nutrition for both mare and foal. The mare’s breed, age, stage of pregnancy, and the nutrient content of the feed/forage supplied must be taken into account when determining your proper feeding plan.

Gestation in the horse is approximately 11 months, or 338-345 days from the last breeding date. In the first two trimesters, the foal is not growing much at all. In fact, at month 7 the foal is only about 20% of its birth weight. The mare’s requirements in the first 7 months do not differ much from that of an adult horse at maintenance—about 1.5-2% of body weight, provided as good quality hay. It is important to make sure you don’t overfeed your pregnant mare; overly fat animals, of most species, have an increased rate of birthing difficulty (dystocia).

Late pregnancy, from month 7 to foaling, is the crucial time when you should ensure your mare is getting all the nutrients she needs. The foal is gaining about 0.75-1 lb. per day in this stage of gestation and the mare’s protein and mineral requirements increase dramatically. The energy requirements only increase by about 15% so again, it is important not to overfeed. Concentrated feed—formulated for gestating mares—will usually supply the appropriate increased amount of protein, calcium and phosphorous that she needs. Trace minerals are also necessary to the health of the mare and foal, most of the gestating mare feeds have this added (a “free choice” supplement may also be used).

Lactating mares also have increased requirements for proteins and minerals. She will also need an additional 10-14 lbs. of grain and forage per day. Be sure to increase the grain in her diet gradually over the last few weeks of pregnancy. Grain amounts can be decreased as the foal approaches weaning, approximately 6 months old, since she will no longer be needed for producing milk.

It is important to have your veterinarian do a nutritional assessment on your mare before every breeding season. This will help you determine what to feed your mare and when, to ensure she has a healthy foal and can be rebred successfully.

Stefani Garbacik is the Livestock and Forage agriculture extension agent for North Carolina Cooperative Extension in Wayne County. If you need further assistance with livestock, animal waste, horse, or forage concerns please contact her at Stefani_garbacik@ncsu.edu or (919) 731-1525. Livestock information can be found at http://wayne.ces.ncsu.edu/.