Horse Feed Management and Gastric Ulcers

Equine gastric ulcer syndrome is caused by inadequate forage feeding and excess acid in the stomach — a highly prevalent and preventable welfare problem in domestic horses.

Key Facts

Equine gastric ulcer syndrome (EGUS) affects over 90% of racehorses and 60% of leisure horses subjected to standard management practices.
Horses evolved to graze continuously — producing saliva that buffers gastric acid throughout the day.
Stabling with restricted forage access allows concentrated acid to damage the unprotected squamous stomach mucosa.
High starch diets from concentrate feeds increase acid production and exacerbate ulcer risk.
Treatment with omeprazole (proton pump inhibitor) effectively heals ulcers, but management changes are required to prevent recurrence.

Welfare Considerations

Gastric ulcers cause chronic pain that affects millions of domestic horses in ways invisible to most owners. Horses with ulcers may show subtle signs — reduced appetite, dull coat, girthing discomfort, or reluctance to work — that are easily attributed to other causes. The underlying driver is simple: horses are being managed in ways that deny them the continuous trickle of forage their digestive system requires. Providing ad libitum hay or equivalent continuous forage is the single most impactful intervention for gastric welfare, preventing ulcers from developing in the first place.

What You Can Do

Ensure your horse has access to forage for at least 16 hours daily — ad libitum hay prevents acid accumulation.
Reduce starchy concentrate feeds and replace with high-fibre feeds that require longer chewing and produce more saliva.
Consider gastroscopy if your horse shows performance problems, reluctance to work, or girthing discomfort.
Work with your vet to combine omeprazole treatment with management changes to prevent ulcer recurrence.