Horse Pituitary Pars Intermedia Dysfunction and Welfare

PPID (formerly known as Cushing's disease) is the most common endocrine disorder of older horses. Early diagnosis and treatment significantly improve quality of life for affected animals.

Key Facts

PPID affects an estimated 20-30% of horses over 15 years old in the UK
The condition results from dysfunction of the pars intermedia of the pituitary gland, causing hormonal imbalance
Classic signs include a long, curly coat (hypertrichosis), pot belly, muscle wasting, and increased thirst
PPID dramatically increases laminitis risk — affected horses should be managed as high-risk for this painful condition
Pergolide medication effectively controls PPID in most horses, improving coat shedding and energy levels
TRH stimulation tests have improved early diagnosis before classic external signs develop

Welfare Considerations

PPID causes progressive deterioration in quality of life that is easily misattributed to normal ageing. Affected horses suffer from chronic laminitis, muscle weakness, and immune compromise that increases disease susceptibility. The stoic nature of horses means significant suffering often occurs before owners recognise the problem. Early diagnosis and medication access substantially changes the welfare trajectory for affected horses.

What You Can Do

Discuss PPID screening with your vet for any horse over 15 showing coat, weight, or energy changes
Monitor summer coat shedding — persistent long coat after May in a temperate climate warrants investigation
Implement laminitis prevention protocols for any horse diagnosed with PPID
Ensure diagnosed horses receive pergolide at the correct dose and that this is reviewed annually
Adjust diet to low non-structural carbohydrate hay and feeds appropriate for metabolic horses
Arrange twice-yearly dental and weight assessments for horses with PPID