Feeding Stallions and Broodmares

Dr. Katie Young, Equine Nutritionist, Purina Mills, LLC

According to Dr. Lon Lewis, author of Feeding and Care of the Horse, a well-managed breeding farm should attain or exceed a foaling rate of 70 to 80% of mares bred or on pasture with a stallion. However, in the United States, only 55 to 60% of mares bred annually produce live foals. There are many factors that affect breeding performance of horses, but perhaps the first issue to be addressed should be the feeding program.

STALLIONS

In many situations, the stallion is the star of the breeding farm. Mare owners spend thousands of dollars on breeding fees, veterinary care, and possibly on A.I. (artificial insemination) shipments. The stallion is then expected to be in excellent physical condition, able to perform on demand when a mare arrives for breeding or when semen is artificially collected. Nutrition is certainly a factor in maintaining the stallion in top health before, during and after the breeding season

For optimal performance, stallions should be maintained in a moderate condition score (Body Condition Score 5-6). Stallions require additional energy during breeding season since they are working harder, and a thin stallion may not have the energy store to make it through the season without compromising performance. On the other hand, obese stallions may have increased risk of laminitis, aggravating arthritis, or even causing a heart attack. There have also been reports of obese stallions exhibiting lowered libido. (see Body Condition Scoring)

Since a stallion works during breeding season, he should be fed similar to a performance horse. A stallion with a heavy breeding schedule may require 25% or more energy (calories) during the breeding season than the non-breeding season. The increased energy needed for the act of breeding is small, but the increased physical activity associated with breeding such as nervousness and pacing may increase the stallion’s energy needs up to 1/3 above the energy required by a horse at maintenance. Protein, vitamin and mineral requirements may also increase during the breeding season, but the increased needs are usually met when the diet is adjusted to meet the increased energy requirements. Some breeders feed Vitamin C and E supplements to enhance the stallion’s reproductive performance, but research has shown that even large doses of these vitamins are not beneficial for this purpose. Purina Strategy or Omolene 200, fed as recommended with good quality hay, would meet the stallion’s nutrient requirements without additional nutritional supplements.

BROODMARES

When feeding broodmares, the feeding program must meet the requirements of the growing foal as well as the mare herself. As the mare progresses through the various Stages of gestation, her nutritional needs change.

During the present time of the year, most mares are either getting close to foaling, or have recently foaled and are in early stages of lactation. Therefore, this article will concentrate on the nutritional needs of mares in late gestation and lactating mares. For more information on feeding open mares or mares during early gestation, please refer to the article “Feeding Broodmares for Optimum Performance.”

Late Gestation

Sixty percent of the unborn foal’s growth occurs during the last three months of pregnancy, so the mare’s protein, energy, vitamin and mineral requirements increase greatly to meet these needs. In fact, the foal’s growth rate increases to about 1 pound per day during this period. In order to meet the mare and foal’s needs, highly fortified feeds such as Strategy and Omolene 200 should be fed along with good quality hay and /or grass. Therefore, during the last months of pregnancy, the mare’s diet should be gradually adjusted to meet the increased nutrient demands, and also to prepare the mare for the increased nutritional stress of lactation, as well as maintain the mare’s body condition for rebreeding.

Lactation

Nutrient requirements for digestible energy in lactating mares depend on the composition and quantity of milk produced. Mares with greater milk production will need more energy (total calories) in their diets. Mares produce an average of 3 gallons of mild daily during a 5-month lactation period. Digestible energy requirements are highest for lactating mares for the first three months after foaling. Depending on the mare, energy requirements may increase up to double the maintenance requirements. Protein requirements are also highest during the first three months of lactation. Early in lactation, the foal requires milk that is rich in energy, protein, calcium and phosphorus, so the mare must be fed appropriately. Keep in mind, however, that a sudden change in feed to meet the mare’s increased need may result in digestive disturbances such as colic. Increases in the mare’s feed should be made gradually over 7 to 10 days to allow the mare’s digestive system to adjust. Either Strategy or Omolene 200 are appropriate to meet the mare’s needs, however, if the foal is allowed to nibble on the mare’s fee, Strategy or Omolene 300 will best meet the needs of both the mare and the foal.

In the fourth, fifth and sixths months of lactation, the mare’s milk supply decreases, therefore her need for additional nutrients declines, and her feeding level should be reduced proportionately to maintain her body condition score for the next breeding season or to support the new pregnancy.

For mares that will be rebred for next year, research has shown that the body condition of a mare at the time of breeding can influence conception rate. Thin mares gaining weight at breeding time are twice as likely to conceive as thin mares maintaining weight. Mares in good to fat condition (Body Condition Score 5.5 to 7.5) have high conception rates even when losing or maintaining body weight. Therefore, dietary energy requirements for reproduction depend on the body condition of the mare. Increasing energy intake 10 to 15% above the requirement should result in weight gain and a higher condition score.

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