Equine gastric ulcer syndrome affects approximately 90% of racehorses and 60% of performance horses, causing chronic abdominal pain that significantly impacts welfare and performance across all equine disciplines.
Gastric ulcer syndrome in horses is a paradigm case of welfare harm created by management practices that conflict with species physiology. Horses evolved as continuous grazers with gastric acid produced to digest a nearly constant stream of forage. Stabling, intermittent feeding, and high-concentrate diets create acid exposure without the buffering forage that horses require for gastric health. The welfare cost is chronic abdominal pain that manifests as behavioral changes — pain from acid contact with ulcerated stomach lining is acute and recurring. The management solution is straightforward: maximize forage access, minimize fasting periods, use slow feeders to extend eating time, and reduce grain proportion. For racehorses with exercise-induced acid splash, medication before work reduces acute acid damage.