Equine Gastric Ulcer Syndrome: Prevalence, Pain, and Prevention

Gastric ulcers affect an estimated 60-90% of performance horses and cause chronic pain and behavioural changes. Understanding causes and prevention is essential for equine welfare.

Key Facts

Equine Gastric Ulcer Syndrome (EGUS) affects 60-90% of racehorses and 37-60% of non-racing performance horses
Horses' stomachs produce acid continuously; without constant forage, the non-glandular region is vulnerable to acid damage
Intermittent feeding, stabling, high-intensity exercise, and NSAID use are major risk factors
Signs include poor appetite, reduced performance, girthiness, colic, and weight loss
Omeprazole (GastroGard) is the gold-standard treatment, typically effective within 28 days
Prevention through forage management — ad libitum hay, forage before exercise — is more cost-effective than treatment
Recurrence rates are high if underlying management factors are not addressed after treatment

Welfare Considerations

Gastric ulcer disease causes chronic pain that significantly impairs equine welfare and performance. The condition is largely iatrogenic — caused by management systems that prioritise convenience and tradition over horses' physiological needs. Horses evolved as continuous grazers; the equine stomach produces acid around the clock regardless of feeding schedule. When horses are stabled and fed twice daily, acid pools in the non-glandular stomach without the buffering effect of saliva and fibrous feed, causing erosion and ulceration. The prevalence rates in performance horses — approaching 90% in racehorses — indicate a near-universal welfare failure in these populations. Prevention through providing ad libitum forage, ensuring horses receive hay before exercise, and reducing NSAID use where possible addresses causes rather than treating consequences.

What You Can Do

Provide ad libitum hay access as the most important single gastric ulcer prevention measure
Feed forage or chaff before exercise to buffer gastric acid during high-intensity work
Ask your vet about EGUS testing if your horse shows reduced appetite, girthiness, or poor performance
Minimise stabling and maximise turnout to reduce EGUS risk through natural continuous grazing
Use omeprazole treatment as prescribed but address underlying management factors to prevent recurrence