Gastric Ulcers in Horses: Symptoms, Causes and Management
Equine gastric ulcer syndrome is common in performance horses — studies of competition horses regularly find a high proportion affected to some degree — and it's also easy to miss, because the signs are often behavioural rather than dramatic. A horse with ulcers rarely looks "sick" in an obvious way; it looks like a horse that's become a bit harder to ride.
Common symptoms
- Girthiness — pinning ears, swishing the tail, or fidgeting when the girth goes up.
- Poor appetite or picky eating, particularly leaving concentrate feed while forage intake stays normal.
- Weight loss or a dull coat despite a workload and diet that hasn't obviously changed.
- Mild, recurring low-grade colic, especially after feeding.
- Change in attitude — a horse that's become more reactive, reluctant to go forward, or resistant to work it used to do without fuss.
- Teeth grinding or excessive salivation in more severe cases.
None of these signs is unique to ulcers on its own — a girthy horse might have back or saddle-fit pain instead, and a picky eater might have dental issues. That overlap is exactly why a vet diagnosis (usually gastroscopy) matters rather than assuming and treating at home.
What causes them
Ulcers form when the stomach's acid exposure outweighs its protection, and several everyday management factors tip that balance:
- Long gaps without forage — the equine stomach produces acid continuously, and forage buffers it; horses without near-constant access to hay or grass go longer with unprotected acid.
- High-starch, low-forage diets, common in horses fed a lot of concentrate for workload.
- Intense or irregular exercise, which increases acid splash onto the unprotected upper stomach lining.
- Stress — travel, competition, stabling changes, or a change in yard routine.
- NSAID use over extended periods, under veterinary guidance, can contribute in some cases.
Management changes that support treatment
Medication (typically a course prescribed by your vet) treats the ulcer itself, but management changes reduce recurrence:
- Maximise forage time. Slow feeders and multiple small hay portions through the day and night reduce the gaps a stabled horse spends with an empty stomach.
- Feed something before exercise. A small forage feed before work buffers acid before the workout increases splash.
- Reduce starch, increase fibre and oil where the workload allows it — discuss the balance with your vet or nutritionist rather than cutting concentrate blindly.
- Turnout and routine consistency where possible; sudden changes in stabling or yard routine are a recognised stress trigger.
Tracking behaviour is how most owners catch it early
Because the early signs are subtle and behavioural, they're easy to write off individually — "he's just having an off week." Logging appetite, girthiness, weight and attitude over weeks rather than days is what turns a string of minor annoyances into a pattern worth showing the vet. See our health logging guide for what's worth recording and how often.
When to call the vet
Persistent girthiness, a drop in appetite lasting more than a few days, ongoing mild colic episodes, or a noticeable change in attitude under saddle are all reasons to book a veterinary assessment rather than waiting to see if it resolves on its own. Ulcers rarely fix themselves, and an underlying cause left untreated tends to recur even after a course of medication ends. Log the pattern in horse health records so you and your vet see the same timeline.
Related: Signs of colic in horses · Horse health logging: what to record · Joint supplements for older horses