High severity

Gastric Ulcers (EGUS)

Equine Gastric Ulcer Syndrome affects up to 90% of performance horses and 60% of pleasure horses. The horse's stomach produces acid continuously, so empty stomachs and stress quickly create painful ulcers in the squamous lining.

Symptoms to watch for

Poor appetite, especially for grain

Weight loss or poor body condition

Dull coat

Behavioural changes: girthiness, irritability, reluctance under saddle

Mild recurrent colic, especially after eating

Bruxism (teeth grinding) in foals

Decreased performance

Common causes

Long periods without forage (stomach acid hits the empty squamous lining)
High-grain diets
Intense exercise (acid splashes upward during work)
Stress from travel, stalling, or competition
NSAIDs (phenylbutazone, flunixin) for prolonged periods
Limited turnout

Prevention

Feed forage continuously — never leave the stomach empty for over 4 hours
Offer a small alfalfa meal before exercise (calcium buffers acid)
Reduce grain; use fat for calories instead
Maximise turnout and reduce stall time
Maintain stable companions and routine
Use NSAIDs only as directed by your vet

What to do

1
Have your vet confirm with gastroscopy — the only definitive diagnostic.
2
Begin a 28-day course of omeprazole (4 mg/kg once daily) as prescribed.
3
Switch to a low-grain, high-forage diet immediately.
4
Provide free-choice grass hay or use slow-feed nets.
5
Add a digestive support supplement once treatment ends.
6
Re-scope after treatment to confirm healing.

When to call the vet

Pick up the phone if…

Call your vet if your horse shows persistent appetite loss, behavioural changes under saddle, or recurring mild colic. Diagnosis requires gastroscopy and prescription medication.

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Educational content only. Not a substitute for veterinary advice.