Horse Cushings Disease: Recognition and Management

Pituitary Pars Intermedia Dysfunction (PPID), commonly called Cushings disease, is a common and progressive condition in older horses requiring lifelong management.

Key Facts

PPID affects an estimated 15-21% of horses over 15 years, making it the most common endocrine disorder of older horses
The disease results from loss of dopaminergic inhibition of the pituitary, causing excess ACTH and cortisol production
Clinical signs include a long, wavy coat that fails to shed, weight loss, muscle wasting, increased thirst, and laminitis risk
The ACTH test is used for diagnosis, with seasonal adjustment of reference ranges required for accurate interpretation
Pergolide (Prascend) treats the underlying hormonal dysfunction and dramatically improves clinical signs when administered daily

Welfare Considerations

PPID causes substantial suffering through the progressive loss of normal physiological function. Laminitis secondary to PPID is the most serious complication and can be severely painful and life-limiting. Horses managed without medication progressively deteriorate, developing muscle wasting, recurrent infections, and poor wound healing. Early diagnosis and treatment with pergolide restores quality of life and reduces laminitis risk significantly.

What You Can Do

Screen horses over 15 years annually for PPID using the ACTH test, particularly before the autumn seasonal rise
Begin pergolide treatment promptly upon diagnosis rather than delaying due to cost or uncertainty
Implement a low-starch, low-sugar diet for PPID horses to reduce laminitis risk
Trim PPID horses more frequently if they fail to shed their coat, as a long coat causes significant heat stress in warmer months