Equine Gastric Ulcer Syndrome: Welfare Burden and Prevention Strategies

Equine gastric ulcer syndrome (EGUS) affects the majority of horses in athletic training, causing chronic pain that affects performance, behavior, and quality of life and requiring systematic prevention.

Key Facts

EGUS affects an estimated 60-90% of horses in active training, making it one of the most prevalent welfare conditions in sport horses
Two regions are affected: the squamous mucosa (ESGD) and glandular mucosa (EGGD), with different etiologies and treatment responses
Prolonged fasting, high-intensity exercise, and high-concentrate diets are primary risk factors for squamous ulceration
Clinical signs are often subtle — poor performance, girthiness, changes in behavior, reduced appetite, or coat condition changes
Omeprazole (Gastrogard) is effective for squamous ulcers but less so for glandular disease
Continuous access to forage is the single most important preventive measure — stomach acid damages unprotected squamous mucosa within hours of fasting
Horses evolved to graze continuously for 16-18 hours daily — intermittent feeding management is fundamentally incompatible with stomach anatomy
High-starch diets increase volatile fatty acid production that damages squamous mucosa, making forage-based diets preferable

Welfare Considerations

Equine gastric ulcer syndrome is a welfare condition created almost entirely by management practices that conflict with horses' evolved digestive physiology. Horses evolved as continuous grazers with a stomach that produces acid continuously and relies on saliva buffering from constant chewing to protect the squamous mucosa. Intermittent feeding, fasting periods, and high-concentrate diets create conditions where unbuffered acid contacts unprotected mucosa, causing the progressive ulceration that affects the majority of horses in athletic training. The welfare burden is significant: gastric ulcer pain is chronic, affects quality of life during every waking moment, and manifests as behavioral changes that are frequently misinterpreted as attitude problems. Management changes — continuous forage access, reduced concentrate feeding, and appropriate work schedules — prevent ulcer development more effectively than treatment. For horses already affected, omeprazole treatment combined with management reform provides welfare improvement.

What You Can Do

Ensure horses have continuous access to forage — hay or grass — throughout the day and night
Reduce or eliminate concentrate feeding where nutritional requirements can be met through forage alone
Provide forage before exercise to buffer stomach acid during the period of increased gastric pressure
Discuss EGUS screening with your veterinarian for any horse showing behavioral changes under saddle or during handling
Consider gastroscopy for definitive diagnosis rather than empirical omeprazole treatment in horses with suspected ulcers
Support research into equine gastric glandular disease which is less well understood and treated than squamous disease