Horse PPID Pituitary Pars Intermedia Dysfunction

PPID (equine Cushing disease) is common in older horses and causes a wide range of welfare problems. Early diagnosis and treatment significantly improve quality of life.

Key Facts

PPID results from dysfunction of the intermediate lobe of the pituitary gland causing excess ACTH production
Clinical signs include a long curly coat that fails to shed (hypertrichosis), laminitis, muscle wasting and PU/PD
Diagnosis is confirmed by elevated resting ACTH or TRH stimulation test results
Pergolide mesylate effectively controls clinical signs in most horses when dose is correctly calibrated
ACTH levels show a seasonal autumn rise requiring dose adjustment to prevent clinical deterioration

Welfare Considerations

Unmanaged PPID causes significant suffering through laminitis pain, immune suppression leading to recurrent infections, and failure to thermoregulate due to abnormal coat. Many horses suffer for years with untreated or inadequately dosed PPID. Annual screening of horses over 15 and twice-yearly dose adjustment during autumn surge significantly improves welfare outcomes for this common disease.

What You Can Do

Screen horses over 15 annually with ACTH blood testing before autumn to guide treatment
Ensure pergolide dose is adjusted upward before the autumn ACTH seasonal surge in August-September
Clip hypertrichotic horses to prevent overheating and skin disease from retained abnormal coats
Feed a low-sugar low-starch diet and monitor closely for laminitis signs throughout the year
Work with a vet experienced in PPID management for dose titration and seasonal adjustment