If the horse or pony has a long shaggy hair coat and a history of shedding late or not at all, it is often assumed that they have Equine Cushing's Disease also known as Pituitary Pars Intermedia Dysfunction (PPID). Cushing’s Disease is a hormonal disease of older horses caused by a benign growth of the pituitary gland at the base of the brain.
More than a shaggy haircoat?
If the horse or pony has the long shaggy hair coat and a history of shedding late or not at all, it often assumed that they have Equine Cushing's disease also known as Pituitary Pars Intermedia Dysfunction.
These horses generally are around 20 years of age, but the disease has been recorded in horses as young as seven years old. A number of hormones are involved, all of which act to cause the loss of the regular cortisol circadian rhythm, resulting in chronically increased cortisol levels.
One of the complexities of knowing whether or not a horse has Cushing's disease relates to the fact that some horses do not always shed their haggy winter coats as expected. Sometimes long hair, which can sometimes be quite shaggy or wavy has other causes, but it is extremely important to have a veterinarian diagnose the problem.
Usually the first thing owners notice when their horse has a pituitary tumor is that the horse fails to shed its hair in the spring. Affected horses develop an excessively long, shaggy hair coat that is often curly or matted.
According to Dr. Tom Lenz, about 60 percent of these horses with pituitary tumors sweat excessively and over 30 percent of them develop secondary diabetes known as Cushing’s disease. The diabetic horses will drink massive quantities of water and will urinate frequently, making it difficult to keep their stall dry.
The horses’ feet grow too long and too rapidly, just like the hair coat, and 25 percent of the affected horses experience unexplained bouts of laminitis. The horses may experience repeated infections. Their skin is often scaly or greasy and susceptible to secondary skin infections.
Despite the fact that the horse’s hair coat continues to grow and does not shed, the mane and tail remain normal. As the tumor enlarges, the horse may become swaybacked and develop a “potbellied” appearance. Many of the horses have unusual deposits of fat behind the eyes, which cause them to bulge slightly.
Pituitary tumors are diagnosed on clinical signs as well as the results of blood and urine tests. Because the signs exhibited by horses suffering from pituitary tumors are varied and may mimic a number of other diseases, a veterinarian should be called upon to give the horse a thorough examination.
The horse’s cortisol and blood glucose levels are helpful in confirming the existence of the tumor. Thyroid-releasing hormone response and dexamethasone suppression tests are also helpful in diagnosing the condition.
Read more about Cushing's disease