As they gain a better grasp of what to look for, veterinarians are diagnosing endocrinopathies (disorders of the endocrine system) in horses more frequently. Chances are, you’re already familiar with some of these diseases: The horse with pituitary pars intermedia dysfunction (PPID, or equine Cushing’s disease), for instance, probably has a shaggy coat, decreased muscle tone, and abnormal sweating. The horse with equine metabolic syndrome (EMS) likely has a cresty neck, fat buildups in abnormal places, and a predisposition for laminitis.

But do you know what a horse with another common endocrinopathy, hyperinsulinemia—HI, otherwise known as insulin resistance—looks like? If the answer is no, you’re not alone. Researchers are still in the process of learning what to watch for to suggest a horse has HI.

At the 2016 American College of Veterinary Internal Medicine Forum, held June 8-11 in Denver, Colorado, Steve Grubbs, DVM, PhD, Dipl. ACVIM, shared the results of a study in which he and colleagues examined the characteristics associated with HI in horses. Grubbs is the equine technical manager for Boehringer Ingelheim Vetmedica Inc., in St. Joseph, Missouri.

Specifically, Grubbs and his coworkers hoped to identify epidemiological characteristics of horses with hyperinsulinemia. Epidemiology simply refers to a study of the patterns, causes, and effects of health and disease conditions, along with risk factors and preventive approaches.

To accomplish this, they collected data on horses of varying ages, sexes, and breeds that exhibited at least one of the following clinical signs:

  • Hypertrichosis (abnormal hair growth);
  • Musc