Albeit from the same genus, donkeys and horses have distinctly different physical characteristics, from their ears to their hair coats. But they differ internally, too.

Researchers recently determined, for instance, that when it comes to diagnosing endocrine and metabolic disturbances, such as insulin resistance, metabolic syndrome, and pituitary pars intermedia dysfunction (PPID, or equine Cushing’s disease), donkeys and horses have significantly different test parameters.

In the past, relatively little research has been conducted on donkeys. But because these hardy animals play an important role in developing countries’ economies, researchers have begun to evaluate how owners and veterinarians can better care for them, including testing for and diagnosing endocrine and metabolic conditions.

Francisco Mendoza, DVM, PhD, MSc, Dipl. ECEIM, and colleagues from University of Córdoba, in Andalusia, Spain, recently took a closer look at how donkeys regulate blood glucose (blood sugar, the body’s most important fuel molecule). Specifically, they aimed to establish normal glucose-insulin values in healthy adult donkeys, as well as evaluate the efficacy of two tests that are commonly used to diagnose insulin resistance in horses:

  • The intravenous glucose tolerance test (IVGTT), in which the veterinarian administers glucose intravenously, then measures the animal’s blood glucose levels over the next several hours; and
  • The combined glucose-insulin test (CGIT), in which the veterinarian administers both glucose and insulin intravenously and measures both levels over the