Researchers and veterinarians are still on a noble quest for the Holy Grail of equine Cushing’s disease (PPID or pituitary pars intermedia dysfunction): a reliable diagnostic test that can detect early stage disease. Several tests and clinical signs can indicate later-stage disease, but still lack the ability to consistently and accurately determine whether a horse is developing the condition. So a group of Canadian researchers recently tested an innovative method for detecting early-stage PPID: hair cortisol levels.

Heidi Banse, DVM, PhD, Dipl. ACVIM, an assistant professor at the University of Calgary Faculty of Veterinary Medicine, in Alberta, shared her team’s findings at the 2015 American College of Veterinary Internal Medicine Forum, held June 4-6 in Indianapolis, Indiana.

“Pituitary pars intermedia dysfunction is the most common endocrine disorder of aged horses, affecting 15 to 30% of horses 15 to 20 years of age,” Banse said.

Caused by an enlargement of the pituitary gland’s pars intermedia (the central part of the pituitary gland located at the base of the brain; essentially, as the pars intermedia enlarges, the horse’s clinical signs become more severe), PPID affects all breeds and types of horses. Common clinical signs include hypertrichosis (abnormal hair growth), abnormal sweating patterns, polyuria and polydypsia (excessive urination and drinking, respectively), and muscle wasting with or without associated weight loss