It’s an unusual horse over the age of 20 who doesn’t have some degree of pituitary pars intermedia dysfunction (PPID, also called Cushing’s disease). PPID causes the pituitary gland to produce less dopamine, leading to excessive secretion of the hormone cortisol by the adrenal gland. This leads to a variety of physical changes, including a thick hair coat, abnormal sweating and increased thirst. Some of these, such as lowered immune function, muscle wasting and an increased risk of laminitis, can shorten a horse’s life.
But as with so many other conditions, it’s wise to consider the possibility of PPID well before old age sets in. “We think of Cushing’s as a disease of older horses, but you need to be on watch for it in a horse’s mid-teens,” says Judd. “Some horses develop it at 14 or 15, and the earlier you can catch it and control it, the better. Even if they don’t yet have an obviously thick coat, the condition is taking a toll on the horse, and you don’t want to wait until the horse founders to consider the possibility he might have Cushing’s.”
Judd starts asking owners questions specific to PPID when horses are about