One of the most reliable methods to confirm equine gastric ulcer syndrome is gastroscopy-—viewing the horse’s stomach through a tube passed down through the nostril. | Photo: Courtesy Danny Holbrook

Sixty percent of performance horses might have gastric ulcers, according to researchers who’ve peered inside stomachs to determine incidence. Fifty percent of foals could have them, and among racehorses the figure can be as high as 93%. In one study, more than one-third of leisure-riding horses exhibited at least mild ulcers and, in another, as many as 75% of Western pleasure horses developed gastric ulcers within eight days of moderate training. And you can’t just wish them away: Only 4 to 10% of equine ulcers heal naturally without treatment.

If these kinds of statistics are causing you to get ulcers of your own, read on. Within the next few pages we’ll explore the ins and outs of equine gastric ulcers, what researchers know about them, and how to treat them and decrease their likelihood of causing your horse distress. 

The Equine Stomach

A horse’s stomach is roughly the size and shape of an NFL football, but softer (and pinker). The lining of the esophagus, running down into it, is thin and smooth, much like the human esophageal lining. But while this lining stops at the stomach in humans, it extends all the way into the first third of the equine stomach, explains Patricia Harris, MA, PhD, VetMB, Dipl. ECVCN, MRCVS, director of science for Mars Horsecare, based in Milton Keynes, U.K., as well as in Dalton, Ohio. This is called the “non-glandular” region of the stomach