Equine Gastric Ulcers: Stomach Pain and Welfare in Horses

Gastric ulcers are extremely common in performance horses and cause significant pain and behavioral change. Understanding their causes and prevention is essential for equine welfare.

Key Facts

Equine Gastric Ulcer Syndrome (EGUS) affects an estimated 60-90% of racehorses and 40-60% of sport horses.
Horses evolved to graze continuously — their stomachs produce acid constantly, requiring near-constant forage to buffer acid levels.
Stabling, restricted grazing, high-concentrate diets, travel stress, and intense exercise all significantly increase ulcer risk.
Squamous ulcers (in the upper stomach) are most common and are caused primarily by acid exposure; glandular ulcers (lower stomach) have different mechanisms.
Signs include poor condition, reduced performance, reluctance to work, teeth grinding, altered behavior, and colic.
Diagnosis requires gastroscopy — direct visual examination of the stomach interior.
Treatment with omeprazole (a proton pump inhibitor) is highly effective; sucralfate is used adjunctively for glandular disease.

Welfare Considerations

Gastric ulcers cause real, chronic pain. Affected horses may show behavioral signs of discomfort — aggression, sensitivity to grooming around the girth, poor performance, and altered eating behavior — but many horses with significant ulcers show few obvious signs. The high prevalence of EGUS in performance horses reflects management systems that fundamentally conflict with equine digestive physiology: restricted forage, high-grain diets, and training stress are all ulcerogenic. Treatment without addressing management causes is ineffective long-term — ulcers recur rapidly when horses return to the same conditions. The welfare imperative is to redesign management around the horse's physiological needs: more forage, less starch, less stress, and more turnout.

What You Can Do

Provide horses with access to forage (hay or grazing) for as close to 24 hours per day as possible.
Reduce high-starch concentrate feeds and substitute with high-fibre, low-sugar alternatives.
Minimise stabling and maximize turnout time — grazing provides continuous buffering against gastric acid.
Seek gastroscopy to confirm ulcer diagnosis before starting treatment — empirical treatment without diagnosis is less effective.
Follow a full course of omeprazole treatment (typically 28 days) and recheck endoscopically to confirm healing.
Review your horse's management holistically if ulcers recur — address the underlying causes rather than treating indefinitely.