Dietary Decisions for Horses with Metabolic Disorders

A number of equine health disorders—severe muscle cramping, laminitis, obesity, Cushing’s disease, skeletal defects—have been found to be caused by or related to dietary management. Though each problem has its own characteristics, they can all be set in motion or aggravated if the horse eats too much starch, either from hay or grain or both. These general guidelines may help horses stay healthy and avoid serious illness.

Equine Cushing’s disease, or pituitary pars intermedia dysfunction, can be managed best on a diet that produces a low glycemic response, limiting or slowing the rate at which carbohydrates enter the bloodstream. Avoid unlimited grazing, feed little or no grain, and base the diet on low-carb hay and a ration balancer pellet. Vegetable oil, rinsed beet pulp, or rice bran are safer ways to provide extra energy for thin horses with Cushing’s disease. Senior feeds often contain high-carbohydrate ingredients and should not be used.

Horses with equine metabolic syndrome are often insulin-resistant, obese, and at high risk for laminitis. Using a forage-based diet, limiting pasture access, and feeding a concentrated balancer pellet should help these horses lose weight while providing necessary levels of protein, vitamins, and minerals.

Two syndromes that can bring on severe muscle cramping, recurrent equine rhabdomyolysis and polysaccharide storage myopathy, have different causes but respond well to the same type of dietary management. These horses tend to do well on a high-fat, low-starch feed rather than a more traditional starch-laden grain mix. Fermentable fibers such as beet pulp and soy hulls are also excellent choices for horses with these types of tying-up.

Managers who are looking for maximum growth often feed large grain meals to young horses. Research has tied bone disorders like osteochondrosis to the high blood levels of sugar and insulin caused by this feeding practice. While the young horses may grow at an astounding pace, they pay the price a few months later when they develop lameness due to defects in the process by which cartilage matures into bone. Choosing concentrates that produce a low to moderate glycemic response is a safer way to produce well-grown, sound horses.

Avoiding or managing metabolic disease involves more than just dietary tweaking. Owners of horses with these conditions can get more specific recommendations from a veterinarian or an equine nutritionist, who will also suggest that any change to a horse’s diet should be made gradually over a period of several days or weeks.