A long, curly coat that fails to shed normally is the classical clinical sign of Cushing’s disease in horses, which is more correctly known as pituitary pars intermedia dysfunction (PPID).
In PPID, the pituitary gland, which is a located at the base of the brain and produces hormones in response to brain signals, suffers damage to the mechanisms that control the levels of these hormones. This leads to an excessive production of specific hormones, which enter the horse’s circulation and affect the whole body.
All breeds and types may be affected, but ponies appear to be at greatest risk. It is usually seen in horses and ponies over the age of 15 years. Mares and geldings are equally affected.
PPID typically develops slowly over a period of several years. It is now thought that many horses and ponies have PPID to some degree, even if they do not show the most obvious signs.
While there is no cure, treatment may extend or improve the horse’s quality of life, but medication is expensive and once started, it is best if it is maintained.
Signs of PPID
The signs of Cushing’s/PPID are often vague and variable, and may easily be confused with other diseases or simply put down to “old age”.