By Vincent Gerber, PhD, DVM, Dipl. ACVIM, ECEIM, FVH, WEVA Treasurer

It has long been recognized that the majority of Thoroughbreds in race training are affected by gastric ulcers; however, less is known about the prevalence of equine gastric ulcer syndrome (EGUS) in sport and pleasure horses.

Recent studies from the United States and Europe, including research performed on Swiss endurance and eventing team horses, revealed that lesions in the gastric mucosa are far more common in nonracehorses than previously assumed: Veterinarians found evidence of ulcers in 42% of top-level three-day eventers, 63% of show jumpers and dressage horses, and 48-73% (pre-season) to 93% (during racing season) of endurance horses.

Many factors can cause or exacerbate gastric ulcers in horses, including diets consisting of high volumes of concentrate feeds, physical exertion, gestation, transportation, weaning, and other stresses. Physical and psychological stress is often mentioned as a suspected cause of EGUS, however equine stress levels are difficult to quantify