The hardest thing about gastric ulcers is that the signs are quiet. They overlap with “attitude,” “being fussy,” or a training problem — so a horse can be uncomfortable for months before anyone connects the dots. No single sign proves ulcers, but a cluster of them, especially in a horse that’s in work, travels, or eats a grain-heavy diet, should put ulcers near the top of the list. For the full picture, start with our complete guide to equine gastric ulcers.
- Picky appetite; eating then backing off feed
- Gradual weight loss or trouble holding condition
- A dull coat and a general “not thriving” look
- Girthiness or sensitivity when saddling
- Irritability or attitude changes
- Resistance under saddle or a drop in performance
- Mild, recurring colic, often after eating
- Loose manure or mild diarrhea
- Teeth grinding (bruxism) or excess salivation
- Sometimes associated with cribbing or windsucking
Behavioral & performance signs
These are often the first thing owners notice, and the most commonly misread. A horse with stomach discomfort may become girthy — pinning ears, swishing the tail, or flinching when the girth is tightened — and more irritable or reactive to handle. Under saddle you may see resistance, reluctance to go forward, or a general drop in performance that doesn’t match the horse’s training. Because these read as “sour” or “naughty,” they’re frequently chalked up to temperament instead of pain.
Physical & digestive signs
On the physical side, watch for a picky or reduced appetite — particularly a horse that starts a meal then walks away, or eats hay but leaves grain. Over time that can show as gradual weight loss, a ribby or poor body condition, and a dull coat. Some horses have mild, recurring colic, often after eating, and others pass loose manure. None of these is unique to ulcers, but together they paint a picture worth investigating.
Do squamous and glandular ulcers cause different signs?
Not in a way you can reliably tell apart from the outside. The two diseases — squamous (ESGD) and glandular (EGGD) — share most of the same signs, and a horse can have both at once. That’s a big reason signs alone can’t direct treatment: the only way to know which region is affected, and how badly, is to look.
Signs in foals
Foals can develop ulcers too, and their signs can escalate faster than in adults. Watch for teeth grinding, excess salivation or drooling, diarrhea, poor nursing, a pot-bellied or unthrifty look, and intermittent colic. A foal that frequently lies on its back may be trying to relieve stomach discomfort. Because foals can deteriorate quickly, any of these warrants a prompt veterinary call.
Call your vet promptly if you see…
- Repeated, worsening, or severe colic
- A horse that goes completely off feed
- Rapid or marked weight loss
- Obvious or persistent signs of pain, or a very dull, depressed horse
These can signal severe ulcers or another serious problem that needs hands-on veterinary care — don’t wait them out.
Seeing some of these signs?
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Why signs aren’t a diagnosis
Every sign above has other possible explanations, and ulcers can also be present with almost no signs at all. So while these clues tell you when to investigate, they can’t confirm ulcers or tell you how severe they are. That takes gastroscopy. If you’re weighing it up, our breakdown of what diagnosis and treatment cost will help you plan.
Everyday gut & calm support from VETR
Alongside a veterinary plan, VETR offers supportive products — digestive and calming supplements — for hard-working and easily-stressed horses.
Shop VETR →Supportive supplements are not a treatment for diagnosed ulcers and don’t replace veterinary care.
Frequently asked questions
What are the first signs of ulcers in horses?
Early signs are usually subtle: a pickier appetite, a slightly duller coat or condition, more girthiness or irritability, and a small drop in performance. They’re easy to mistake for attitude or a training issue, which is why ulcers are so often missed.
Can gastric ulcers cause behavior changes?
Yes. Discomfort from ulcers commonly shows up as irritability, sensitivity when girthing or saddling, resistance under saddle, and general attitude changes.
Do ulcers cause weight loss in horses?
They can. A horse with ulcers may eat less or back off feed, and ongoing discomfort can make it hard to hold condition, leading to gradual weight loss and a poor coat.
Can a horse have ulcers without obvious symptoms?
Yes. Many performance horses have ulcers with only subtle signs or none at all, which is why vets often recommend scoping high-risk horses even when they seem fine.
Is girthiness a sign of ulcers?
Girthiness and belly sensitivity are commonly associated with ulcers, though not proof on their own. Alongside other signs, they’re worth investigating.
How can I tell if my horse has ulcers without scoping?
You can’t confirm ulcers from signs alone. Clusters of signs raise suspicion, but gastroscopy is the only way to confirm ulcers, grade them, and tell squamous from glandular disease.
References & sources
- Merck Veterinary Manual — Stomach (Gastric) Ulcers in Horses
- Sykes BW, et al. ECEIM Consensus Statement: Equine Gastric Ulcer Syndrome in Adult Horses. J Vet Intern Med. 2015;29(5):1288–1299.
Dosing figures follow FDA-approved label rates for omeprazole; cost ranges are general market estimates. Always confirm diagnosis, dosing, and treatment with your veterinarian.