From AAEP’s Ask the Vet: Feeding the Race Horse

In your opinion, what is the best feed combination for a race horse in racing season and during rest period? Should it be different due to the different energy demands? Is there need for supplementation? Thank you! – Edward

Dear Edward,

Absolutely a race horse should be fed differently during race season than during the off season! Racing constitutes “very heavy work” according to the NRC Nutrient Requirements of Horses and is one of the categories where hay alone cannot meet the horse’s energy, or caloric, requirements. When a horse is working hard, he needs his diet to become more calorie-dense because he needs more calories but is still volume-limited to that 2.5 maybe 3% body weight of feed intake per day. Hard-working horses can get to the point where they need more calories but simply can’t take in any more food so the food they eat needs to have more calories per pound.

With some horses, this can be accommodated by reducing hay and increasing fortified grain. Look for a grain that is specially developed for very active horses or horses in hard work and be sure not to feed more than 0.5% body weight in grain per meal (that’s 5 pounds for a 1000 pound horse). Studies have shown that more than this amount of sugar and starch given at one time overwhelms the stomach and small intestine, winds up in the hindgut, and can cause all sorts of problems like colic and even laminitis.

Be forewarned, even if you are under the 0.5% per meal limit, many horses are unable to handle such high amounts of sugars and starches from traditional grains. These horses can develop behavioral issues, exertional rhabomyolysis (tying up) or other conditions. In these cases, fat has been shown to be an excellent source of calories! Nowadays there are many choices for adding fat to the diet, whether it’s a grain with a higher percentage fat, a supplement made from rice bran or other high-fat ingredient, 100% powdered fat supplements, or oils. Just keep in mind that all fats are not created equal so try not to imbalance your horse’s omega 3:omega 6 fatty acid ratio with an oil or fat that is loaded with the pro-inflammatory omega 6s (like corn oil). Good luck (in the feed room and on the track!).