Horse Gastric Ulcer Prevention in Performance Horses

Understanding why equine squamous and glandular gastric ulcers are endemic in performance horses and evidence-based prevention strategies.

Key Facts

Equine gastric ulcer syndrome (EGUS) affects over 90% of racehorses and 60–80% of other performance horses in active training
Two distinct syndromes exist: squamous ulcers caused by acid splash, and glandular ulcers with a more complex pathophysiology
Horses produce hydrochloric acid continuously — prolonged fasting allows acid to pool in the squamous mucosa, causing ulcers within hours
Signs include poor performance, girth sensitivity, reduced appetite, mild colic and behavioural changes — many horses show no obvious signs
Omeprazole is the primary treatment and prevention tool for squamous disease; sucralfate and misoprostol are used adjunctively for glandular disease
Dietary factors — access to forage, timing of concentrate feeding and the type of forage — are modifiable risk factors

Welfare Considerations

EGUS prevalence in performance horses represents an endemic welfare crisis normalised by its ubiquity. A condition affecting over 90% of racehorses cannot be characterised as exceptional — it is the predictable outcome of management practices that include prolonged stabling, restricted forage access, high-starch concentrate diets and training-induced physiological stress. The assumption that poor performance or behavioural change in a racehorse reflects "training resistance" rather than gastric pain has historically delayed welfare-appropriate treatment. Welfare-aligned management centres on continuous forage access, reduced concentrate load and pre-exercise forage provision — strategies that reduce ulcer risk without compromising training objectives.

What You Can Do

Ensure forage is available at all times — never allow more than 4 hours without hay or pasture access
Feed a small amount of forage before exercise to buffer gastric acid during the period of greatest splash risk
Reduce non-structural carbohydrate in the diet where possible — alfalfa/lucerne hay provides calcium buffering alongside fibre
Scope horses showing poor performance, girth sensitivity or behavioural changes before assuming a training problem
Consult your vet about omeprazole treatment for confirmed squamous ulcers and longer-term prevention strategies
Maintain social group housing where possible — isolation increases cortisol and gastric acid secretion