Insulin Resistance in Horses

If youve been around horses a while youve probably seen the following a horse that isnt a stallion with a really thick crest and fat pads along the withers at the base of the tail and virtually anywhere along the trunk. The horse may also have fat deposits in the fossae above the eyes. While we could think a horse like that is just obese he could also be suffering from a serious condition that needs medical management
Approximately 10 percent of horses in the United States have been diagnosed with insulin resistance. Insulin resistance is a type of equine metabolic irregularity that falls under the umbrella of equine metabolic syndrome EMS. In addition another 10 percent of horses who have Cushings disease or pituitary pars intermedia dysfunction PPID are also insulin resistant.

What is Insulin Resistance?
The term insulin resistance has only become well recognized in the last 15 years. With a horse like the one described above there are internal forces at work that cause these clinical signs.
Insulin resistance is a state where insulindependent cells of skeletal muscle fat and liver dont respond normally to insulin requiring higher levels of insulin to get them to take up glucose from the blood says Eleanor Kellon VMD. Kellon is currently the staff veterinary specialist of Uckele Health and Nutrition based in Blissfield Mich. She is also the owner of the consulting business Equine Nutritional

 Solutions and the owner and volunteer veterinary advisor for the Equine Cushings and Insulin Resistance ECIR Group Inc. which provides the latest research diagnosis and treatment information for horses with these conditions.
Although there are some situations where a horse may only be insulin resistant for a short time generally the condition has a genetic component and is one that the horse will face longterm. While Thoroughbreds Standardbreds warmbloods Quarter
Horses and fullsized draft breeds are generally at the most risk for IR if they are diagnosed with PPID the Morgan Arabian Andalusian and other Spanish breeds Miniature Horses gaited breeds Fjords Icelandics and most ponies are automatically considered high risk.

Things like some drugs and serious infections may cause temporary insulin resistance but otherwise the cause is genetic Kellon says. Because it is genetic the tendency to have high insulin will always be there but most horses can be well controlled by diet and exercise.
Outside of the genetic component or potentially a diagnosis of PPID mares in the last half