Cushings disease occurs in horses, dogs and even people. However, the symptoms are different, depending on the species. In horses it results in increased hair growth (longer, thicker, curly) whereas in dogs it results in hair loss and even bald spots. The horse version of this illness is called ECD (Equine Cushings Disease).

As a horse ages, there is an increasing tendency for the pituitary gland to develop tumors or to grow too large, resulting in it producing more hormones. This in turn stimulates the adrenal glands to produce additional steroids and when the level of steroids becomes excessive it results in cushings. Since these changes are age related, ECD is most often found in horses over 15 years but has been found in horses as young as seven.