Equine Gastric Ulcer Syndrome (EGUS) is exceptionally prevalent in performance horses, affecting up to 90 percent of racehorses and causing chronic pain that significantly impairs welfare and performance.
Gastric ulcers cause chronic pain that horses cannot communicate directly — many horses with confirmed severe ulceration show only subtle behavioural signs that owners may not recognise as pain. The condition is fundamentally a welfare consequence of keeping horses in ways incompatible with their digestive physiology: horses evolved to graze for 16-18 hours daily, producing saliva that buffers stomach acid continuously. Management practices that restrict forage access and increase grain feeding create the conditions for ulcer development. Prevention through maximising forage access, reducing starch intake, and minimising transport stress addresses welfare at source rather than simply treating the consequence.