Horse Gastric Ulcers: Prevention in Working Horses

Equine gastric ulcer syndrome (EGUS) is extremely prevalent in performance horses and causes chronic pain. Prevention through management is the most effective welfare strategy.

Key Facts

EGUS affects 60-90% of racehorses and 40-60% of performance horses
The equine stomach produces acid continuously regardless of feeding — prolonged fasting allows acid accumulation
Training, transport, and stress all increase ulcer risk significantly
Omeprazole (GastroGard) is the gold standard treatment, resolving most ulcers within 28 days
Without preventive management, ulcers recur rapidly after treatment cessation
Horses should have continuous forage access (at least 1.5% body weight daily) to buffer gastric acid

Welfare Considerations

EGUS causes chronic pain that affects behavior, performance, and quality of life in working horses. Affected horses show signs including girthiness, reluctance to work, subtle behavioral changes, and weight loss. Because horses mask pain effectively, ulcer-related discomfort is often attributed to behavioral problems and addressed with training pressure rather than veterinary investigation. The welfare imperative is to consider EGUS whenever a performance horse shows unexplained behavioral changes.

What You Can Do

Provide continuous access to hay or turnout to maintain forage in the stomach at all times
Avoid prolonged periods without forage — overnight fasting significantly elevates ulcer risk
Feed a small amount of forage or chaff before exercise to buffer the stomach
Minimize unnecessary stress from transport, stabling changes, and social disruption
Investigate behavioral changes in working horses for underlying pain, including gastroscopy if indicated
Implement preventive omeprazole treatment during high-stress periods such as competition travel