Many pleasure horses can easily survive and prosper off hay alone. Elite athletic horses, however, need their diets customized to meet their specific dietary requirements, as hay alone often does not provide enough energy (calories).

"As with all types of horse, forage is the foundation of a performance horse’s feeding program," said Joe Pagan, PhD, president of Kentucky Equine Research in Versailles, Ky. Pagan was scheduled to present at the 12th Congress of The World Equine Veterinary Association, held Nov. 2-6, 2011, in Hyderabad, India, however a last-minute change prevented him from attending. caught up with him after the fact to discuss supplementing performance horse diets.

"Typically, performance horses require about 1.5% of their body weight per day as good quality grass or grass-legume mixed hay," he said. "This quantity of forage will promote digestive tract health, but most likely will not meet the performance horse’s energy requirement."

Thus, his energy requirements will need to be supplemented. But with the myriad of supplements that tantalize trainers and owners alike, how exactly does one avoid unnecessary supplements and only purchase what is really needed?

"An effective supplementation strategy for performance horses hinges around understanding what is missing from the primary constituents of a ration," advised Pagan.

The first level of supplementation includes an energy-dense concentrate mix that is fed to meet the horse’s energy requirement. An easy way to know if a horse’s energy requirements are being met is by assessing body condition; according to Pagan, most performance horses should have a body condition score of 5-6 on the Henneke body condition scale.

"Ideally, the concentrate will be fortified with a broad spectrum of vitamins and minerals that cover the performance horse’s requirements," he noted. "With only these two feedstuffs–forage plus concentrate–approximately 90% of a performance horse’s nutrient needs are satisfied."

What is the remaining 10% of a performance horse’s ration?

Pagan said every high performance horse that produces copious amounts of sweat needs a supplemental source of electrolytes such as a free choice salt block or a commercial electrolyte containing sodium, chloride, potassium, magnesium, and calcium.

Other supplements for specific needs could be required, he noted. Popular supplements in this category include joint supplements that generally contain glucosamine, chondroitin sulfate, and methylsulfonylmethane (commonly known as MSM), or high molecular weight hyaluronic acid.

Newer classes of supplements address gastrointestinal health and include protected buffers to reduce hindgut acidosis, antacids, and coating agents to reduce the severity of gastric ulceration. Finally, supplements that address hoof and skin problems, which usually contain biotin as well as various other keratin-promoting ingredients such as zinc and methionine, are also extremely popular. (For more on the efficacy and science behind nutraceuticals, take a look at The Science Behind Equine Nutritional Supplements.)

Finally, he added, deodorized, flavored fish oil contains a high concentration of long chain omega-3 fatty acids, which have a range of beneficial effects for performance horses.

While forage should remain the basis of the equine diet, performance horses typically need additional supplementation to meet their increased energy requirements, Pagan suggested. To ensure a horse is receiving adequate but not excessive supplementation, consult a veterinarian or equine nutritionist.