Equine Cushings disease, also known as pituitary pars intermedia dysfunction (PPID), is a hormonal disease caused by changes in the pituitary gland, which is located at the base of the brain. The disease is most commonly found in horses over 15 years of age. The cause of the condition is not completely understood, but it is thought that as part of the aging process, some horses develop enlargement of part of the pituitary gland, which produces excessive hormones that are important in controlling various body functions. These hormones are known as POMC hormones (pro-opiomelanocortin-derived peptides) and include MSH (melanocyte stimulating hormone), CLIP (corticotropin-like intermediate lobe peptide), beta-endorphin, and ACTH (adrenocorticotrophic hormone) . As the abnormal functioning of the gland produces an excessive amount of a range of different hormones, clinical signs can be variable from horse to horse. Some of the clinical signs of Equine Cushing's disease include:

• Excessive coat length
• Weight loss
• Increased sweating
• Excessive drinking and urination
• Laminitis

It can be hard to make a firm diagnosis in the early phase of the disease. There are a number of medical treatments that can control the disease, but it is incurable.