February 01, 2021

Several sessions during the American Association of Equine Practitioners’ 2020 Virtual Convention & Trade Show, held Dec. 1-18, focused on the nutritional needs of performance horses and what veterinarians need to know when feeding an equine athlete.

Krishona L. Martinson, PhD, a professor and equine specialist at the University of Minnesota, said during the session “How to Select Forages for Equine Athletes” that defining a performance horse is important.

An equine that does moderate, heavy, or very heavy work three times a week, with an elevated heart rate of more than 90 beats per minute with some specialized training is considered to be a performance horse, Dr. Martinson said.

The intensity of work will also determine a horse’s required calorie intake. For example, a horse doing moderate to very heavy work requires 23-34.5 Mcal of digestible energy a day, whereas an idle horse only requires about 15 Mcal a day.

It’s all in the hay

Dr. Martinson said performance horses are under a lot of stress, so veterinarians must maximize intake of forages such as long-stem hay or pasture grasses for healthy digestion.

Ideally, forages should make up at least 50% of digestible energy.

Dr. Martinson said that to select the best forage for a performance horse, you need to start with a physical evaluation of the forage.

“It can’t tell you everything, but it is a really important first step,” Dr. Martinson said.

The following are key factors in a physical forage evaluation:

• Species of plants. Legumes are more nutrient dense than cool-season or warm-season grasses. 
• Maturity as determined by the number of seed heads and stem size of the plants. 
• Color or vibrancy. The forage should be greenish.
• Smell and touch to determine if the forage is free of mold and dust.

Dr. Martinson said the next step is chemical analysis, which helps to determine the moisture level of the hay and its nutrient values.

From a forage perspective, when horses are in training or performing, it may be necessary to add in legumes, reduce the maturity, increase the foraging time, and increase the amount fed, Dr. Martinson said

Concentrated nutrients

Stephen E. Duren, PhD, an equine nutritionist with Performance Horse Nutrition, said during his session, “How to Select Concentrate for Performance Horses,” that the goal is to feed the smallest amount of concentrate that will satisfy the nutrient requirements and maintain body condition score. But the challenge for equine practitioners is determining which concentrate is best for each horse.

Dr. Duren said the mathematical formula, which subtracts the nutrients provided by the forage from the nutrient requirement of the exercising horse, is the best way to determine which concentrate to feed. The deficit amount represents the amount of nutrients the horse must get from a concentrate.

Several software programs will do the calculation, such as FeedXL, KER MicroSteed, and PHN EquiBalance.

Dr. Duren’s standard recommendation for feeding a performance horse is to provide free-choice access to hay and look for a concentrate specifically intended for performance horses.

Healthy gut

Dr. Kelly R. Vineyard, a senior nutritionist of equine technical solutions at Purina Animal Nutrition, discussed digestion during “How to Feed Performance Horses for Optimal Digestive Health.”

Reduced pasture feeding and increased stabling is a part of the modern-day management of horses, but these conditions are not optimal for the equine athlete, Dr. Vineyard said. The stressful conditions can increase digestive disturbances such as gastric ulcers, recurrent colic, and conditions that involve inflammation of the bowel.

“With these athletes, we create sort of the perfect storm of poor conditions for digestive health in the horse,” Dr. Vineyard said. Those really come down to these key points: reduced access to forage; an increased reliance on meal feeding, feeding high-starch, grain-based meals; increased confinement in stalls; stressful training environments; and overuse of nonsteroidal anti-inflammatory drugs.

Dr. Vineyard suggested the following strategies to counteract potential gastrointestinal disturbances:

• Feed quality forage, and use small-hole hay nets, which require horses to eat in a way that mimics grazing behavior.
• Select concentrates to avoid a starch overload, and feed hay before any concentrate to extend the intake of a meal.
• Feed transition should be done gradually to promote digestive health. For example, hay changes should, at a minimum, take a few days to two weeks.