Managing Insulin Resistance Through Diet and Exercise

Insulin-resistant horses are prone to laminitis, but owners and veterinarians can often successfully manage them through strict diet and exercise regimens so that they don't develop laminitis. Ray J. Geor, BVSc, PhD, Dipl. ACVIM, professor and Chair of the Department of Large Animal Clinical Sciences at Michigan State University, outlined some of those regimens at the Sept. 17-18 Laminitis West Conference in Monterey, Calif.

"We've got two opportunities for intervention," said Geor. "First, we've got animals that we know have had laminitis and also show evidence of obesity and insulin resistance (also called equine metabolic syndrome, or EMS). Second, we may identify a horse or pony with clinical features of EMS, even though laminitis has yet to be detected—in both situations, the goal is to manage the obesity and insulin resistance so that episodes of laminitis are avoided."

In designing a diet and exercise program, Geor first stressed the importance of a thorough baseline clinical assessment. That includes not only checking body weight and body condition score and blood-insulin levels, but also evaluating the horse's current feeding program, its level of physical activity, and whether or not it is sound for exercise.

Set realistic goals for weight loss and develop a monitoring plan. Geor indicated that weight loss of 0.7-0.8% of initial body weight per week over a three- to four-month period is a realistic target. However, he also emphasized that there is wide variation in response between animals and this target might be a little ambitious for some horses and ponies. So, every horse should be treated individually, he noted, and it is often necessary to adjust the feeding and exercise program based on responses measured over the first four to six weeks of a weight-loss program.

For weight loss, Geor recommended that the horse have no access to grain, treats, or uncontrolled pasture grazing. Hay or the equivalent is the diet cornerstone, initially fed at about 1.2% of body weight a day, which for a 1,100-pound horse is 13 pounds daily. Decrease the caloric content by feeding hay that was harvested at late maturity. Hay can also be soaked to reduce its sugar content. A ration balancer that provides essential vitamins and minerals can be fed along with the hay, typically no more than 1-1.5 pounds a day.

Although there isn't much data available yet from studies evaluating the effects of exercise in obese, insulin-resistant horses, Geor said that exercise most likely helps these animals. He emphasized that an exercise program must be combined with dietary restriction. However, "starting an exercise program in a horse or pony that has had a recent episode of laminitis is tricky because there is a risk of causing more damage to the feet," he noted. Your veterinarian needs to give the all-clear, and the horse must be monitored closely.

Lastly, Geor recommended increased turnout for confined horses in a large dry lot along with structured exercise. Begin with light exercise, perhaps 10-15 minutes a day, three to four days a week. Be sure the horse works on a good (forgiving) surface, and monitor his feet carefully. Then gradually increase the frequency and duration if he is comfortable.

About the Author

Tracy Gantz

Tracy Gantz is a freelance writer based in Southern California. She is the Southern California correspondent for The Blood-Horse and a regular contributor to Paint Horse Journal, Paint Racing News, and Appaloosa Journal.

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