What Is Cushings Disease in Horses?

Cushing's disease is a condition in which the gland that produces hormones, the pituitary gland, malfunctions as a horse ages. The cause of Cushing's disease is not known, but it affects many of the horse's bodily functions. Horses develop numerous symptoms with Cushing's, a condition for which there is no cure.

  1. Significance

    • The pituitary gland is found in the brain, and produces hormones and other chemical substances that are released into the horse's body. Horses with Cushing's disease have a hyperactive pituitary that fails to shut down, producing too many of these hormones. The gland can start to grow and even press against the horse's brain, resulting in nerve troubles in severe cases. The pituitary gland also affects the adrenal gland next to the kidneys, which means more problems for the horse.

    Effects

    • Cushing's is suspected when an older horse suddenly grows a long coat that remains wavy and thick all year long. The horse will be very sluggish and tend to sweat very easily. Affected animals are subject to high fevers and will drink and urinate much more than normal. They can develop laminitis, a condition of the hoof that is quite painful. Immune-system troubles and sores and wounds that will be slow to heal are also signs of Cushing's disease in horses, as well as sinus problems and hoof and tooth abscesses.

    Time Frame

    • The majority of Cushing's cases occur when a horse is in its late teens or 20s. As the disease continues over time, the horse undergoes more changes. The animal will metabolize protein in a way that makes some muscles break down and others weaken. A pot belly can develop, and the legs can become stiff. Neurological symptoms are a distinct possibility if the pituitary gland becomes large enough. Many of those symptoms can be serious and lead to death.

    Prevention/Solution

    • A drug that humans take for Parkinson's disease has proven to be of use for horses with Cushing's disease. Pergolide tries to shut down the extra activity of the pituitary glands, and has few serious side effects. Other drugs are used to work on the adrenal glands. The horse's diet will need to be changed to limit sugars; the focus is to put weight back on the horse.

    Considerations

    • A common misconception about Cushing's disease in horses is that the thyroid gland is somehow involved--but it is not. Cushing's is not hard to diagnose, and if it is found early, the treatment, while unable to cure the condition, can allow the horse to have a somewhat normal life. Horses with advanced instances of Cushing's disease can still live a long time and have a decent quality of life.