It’s spring, yet your aging equine has failed to shed his long, shaggy, winter coat. Furthermore, he’s developed a saggy belly coupled with loss of muscle over his croup and rump. He’s gulping down far more water than he used to, and his stall is always wet. All these are the classic signs of pituitary pars intermedia dysfunction (PPID), more commonly known as equine Cushing’s disease or Cushing’s syndrome.

Cushing’s is a disorder that likely affects more than half the population of horses aged 14 years and older, according to studies performed by Frank M. Andrews, DVM, MS, Dipl. ACVIM, professor and section chief of large animal medicine, and his research team (Nicholas Frank, DVM, PhD, Dip. ACVIM, assistant professor of large animal internal medicine; Carla Som-mardahl, DVM, PhD, BS, Dipl. ACVIM, assistant professor of equine medicine and pathology; and Hugo Eiler, DVM, PhD, MS, professor in the department of comparative medicine with a specialty in physiology) at the University of Tennessee (UT) College of Veterinary Medicine. If unmanaged, affected horses are at risk for laminitis, disordered glucose homeostasis (a “pre-diabetic” condition), and hoof soreness, and they are immune-suppressed, increasing their risk of numerous infections.

Clearly, this is a disease to be taken seriously.

The term “Cushing’s” is broadly used to represent any clinical situation attributed to the action of excess glucocorticoids (any group of steroid hormones involved in metabolism), such as administration of glucocorticoid drugs and adrenal gland tumors, explains Philip J. Johnson, BVSc (Hons), Dipl. ACVIM, Dipl. ECEIM, MRCVS, professor of equine internal medicine at the University of Missouri at Columbia (UMC) and spokesperson on behalf of the UMC equine endocrinology team (including Nat T. Messer IV, DVM, Dipl. ABVP, associate professor of equine medicine and surgery, and Venkataseshu Ganjam, DVM, PhD, professor of veterinary biomedical sciences). PPID speaks specifically to the common pituitary disease in horses–it is one form of Cushing’s in this species, and it is by far the most common