Certain feeding strategies can help your horse weather equine Cushing’s disease.

Your horse has equine Cushing’s disease, for which there’s no cure. You’ve consulted your veterinarian for advice and have a good handle on routine care and medical management, but you might still be missing a key component to his care: his diet. Nutritional management can make a measurable difference in how your Cushing’s horse thrives.

First, Some Background …

To understand the science behind nutritional management of Cushing’s, it’s important to first grasp the condition’s essential mechanisms. Cushing’s is more correctly referred to as pituitary pars intermedia dysfunction, or PPID–a condition of the pituitary gland, which is located at the base of the brain. In the healthy brain, the hypothalamus produces a neurotransmitter called dopamine, which regulates the pituitary gland’s production of adrenocorticotropic hormone (ACTH). A tumor in or hypertrophy (enlargement) of the pituitary gland exerts pressure on the hypothalamus, causing a reduction in dopamine secretion; consequently, the pituitary pars intermedia cannot stop releasing ACTH.

Since ACTH stimulates the adrenal gland to produce the hormone cortisol (which at high levels elevates blood sugar), uncontrolled ACTH release can cause tissues to become insulin resistant (IR), or unable to control blood sugar levels with normal amounts of the hormone insulin. Thus, insulin levels rise in the bloodstream. The result is often laminitis–inflammation of the sensitive laminae that connect the horse’s hoof to the coffin bone–but the exact mechanism is still unclear.