Gastric ulcers in horses: the signs under saddle, the causes and what helps

Common signs of gastric ulcers in horses are girthiness, resistance or a drop in performance under saddle, picky eating, weight loss, a dull coat and mild or recurring colic. None of them proves it. Only a vet’s gastroscopy can confirm ulcers.

That second part gets lost on yards. Ulcers have become the default explanation for any horse that is grumpy to tack up, and sometimes they are right. A girthy horse can just as easily have a sore back, a saddle that pinches, or a hind leg that hurts.

What are the symptoms of gastric ulcers in horses?

The European College of Equine Internal Medicine consensus statement on gastric ulcers lists the signs that have been reported: poor appetite or picky eating, poor body condition or weight loss, a poor coat, teeth grinding, behaviour changes including an aggressive or nervous temperament, acute or recurrent colic, chronic diarrhoea and poor performance. The British Horse Society’s EGUS guide adds a dull demeanour, crib biting, and grumpiness when being girthed, rugged or groomed.

The consensus authors also say these signs are non-specific and poorly associated with ulcers being present. Plenty of horses with ulcers show none of them, and the BHS notes that some stoic horses show no signs at all.

So treat the list as a reason to ask, not an answer. Ulcers are common: the consensus statement puts squamous ulcers at 17 to 58% of show and sport horses and 37 to 59% of pleasure horses, falling to 11% in horses rarely competed and mostly used at home.

Signs that can point to ulcers, and what else to rule out

What are the signs of ulcers in horses under saddle?

The BHS lists resistance to the aids and reduced performance. In practice that tends to look like:

• Girthiness: ears back, turning to nip, or tensing as the girth goes up
• Reluctance to go forward
• Tension or tightness, or a horse that gets worse as the work gets faster
• Napping, bucking or kicking out at the leg, particularly into canter
• Simply going less well than a month ago

There is a physical reason faster work can bother an ulcered horse. The consensus statement explains that at gaits faster than walk, pressure inside the abdomen pushes acid up onto the unprotected upper lining of the stomach.

But every sign in that list is also a sign of pain somewhere else. The best data on girthiness comes from a University of California, Davis review of 37 girthy horses published in the Journal of Equine Veterinary Science in 2019. Twelve were diagnosed with gastric ulcers, 10 with orthopaedic problems, 3 with ill-fitting saddles, and the rest with a mix of conditions including liver, sternum and urinary problems. Ulcers were the most common single finding, and 92% of the horses that were scoped had them, but most of the girthy horses had something else.

So think about lameness and the saddle as well as the stomach. Our guide to a horse that won’t canter on one lead covers the ridden signs of musculoskeletal pain, which overlap with these a great deal.

What causes ulcers in horses?

Horses produce stomach acid all the time, not just when they eat. The BHS explains that they evolved to trickle feed for up to 18 hours a day, and the saliva from chewing buffers that acid. When the stomach sits empty, or acid splashes up during work, the unprotected upper lining takes the damage.

The risk factors from the consensus statement and the BHS:

• Long gaps without forage. More than six hours between forage meals raises the likelihood of squamous ulcers, and fasting is a well described cause.
• Starchy hard feed. More starch is the most consistent dietary link. Going over 2g of starch per kg of bodyweight a day, which is 1kg of starch for a 500kg horse, roughly doubled the likelihood of moderate or worse squamous ulcers.
• Grain before hay. Stabled horses fed grain an hour before their hay had a marked increase in ulcers.
• Straw as the only forage. It is fine as part of a ration, not as all of it.
• No constant water. Horses without water in their paddock were more than 2.5 times as likely to have ulcers.
• Exercise, especially faster and longer work. In endurance horses, severity rose with the distance of the ride.
• Stress: travelling, competing, intensive training, little contact with other horses and restricted turnout.
• Long courses of anti-inflammatories such as bute, which reduce the stomach’s own protection.

What is the difference between squamous and glandular ulcers?

Vets use the umbrella term equine gastric ulcer syndrome (EGUS), and since the 2015 consensus statement they split it in two, because the two halves of the stomach behave differently.

• Equine squamous gastric disease (ESGD) affects the upper part of the stomach. This lining has no protective mucus, and the ulcers are mostly caused by acid reaching it. This is the type most of the risk factors above apply to.
• Equine glandular gastric disease (EGGD) affects the lower part, which makes acid and is normally protected by mucus. Its causes are still poorly understood, and the dietary advice is based mostly on research into squamous ulcers.

Glandular ulcers are not rare. The consensus statement cites a UK study that found them in 54% of 191 leisure horses and 64% of 493 sport horses. It also says one type tells you nothing about the other, which is one more reason the scope matters.

How are gastric ulcers in horses diagnosed?

By gastroscopy. Your vet passes a long, thin camera up the nose, down the oesophagus and into the stomach, with the horse sedated. The BHS says the horse usually needs to be starved for at least 12 hours first so the stomach is empty enough to see. The vet looks at the whole stomach, including its exit, and grades anything they find.

The consensus statement is firm on this. It calls gastroscopy the only reliable way to identify ulcers in a live horse, says there are no reliable blood markers, and found no link between gastric ulcers and blood or albumin in droppings. It does not support diagnosing ulcers from the signs alone, and does not recommend starting treatment without a scope.

If a course of treatment is tried without a scope and the horse doesn’t improve, the consensus says a gastroscopy is still needed.

What is the treatment for ulcers in horses?

Treatment is prescribed by your vet, and the right plan depends on which type of ulcer the horse has and how bad it is.

In general terms, the main medicine reduces how much acid the stomach makes, so the lining has time to heal. Omeprazole is the best studied, and the BHS names it as the usual medicine for more severe cases. Squamous ulcers respond best. Glandular ulcers tend to be harder, and the consensus statement suggests a combination of medicines and a recheck at around four weeks.

• Not every ulcer heals in one course. The consensus says at best about 70 to 80% of squamous ulcers heal within 28 days, and recommends a repeat scope before stopping treatment.
• Antacids and supplements are not a substitute. Antacids give relief that lasts two hours at most, and the consensus says they are not justified as the only treatment. Some supplements show promise in studies, but none replaces a diagnosis.

Management changes go alongside medicine. Without them, whatever caused the ulcers is still there when the course ends.

How do you prevent ulcers in horses?

Most of this is about keeping something in the stomach and keeping stress down:

• Forage little and often. Aim for no gaps of more than about six hours. Ad lib hay, or at least four to six forage meals a day when grass is short, with small-holed nets for a horse on a restricted ration. Our guide to how much hay a horse needs covers the overnight gap that catches most British yards out.
• Chaff or hay before you ride. The BHS suggests an average scoop of chaff, or about 2kg of hay or haylage, around 30 minutes before exercise, for stabled and field kept horses alike, to help stop acid splashing onto the upper stomach during work.
• Keep hard feed low in starch, split into as many small meals as you can, and fed after forage, not before. The consensus suggests no more than 1g of starch per kg of bodyweight in a single meal. A nutritionist can check the numbers.
• Constant clean water, in the field as well as the stable.
• Change the diet gradually, over 10 to 14 days.
• Turnout with company, as much as you can. The evidence on turnout is mixed, and the BHS points out that a bare field does not do the job. There needs to be grass to graze.
• Plan travel and competition days: a haynet for the journey and forage before you ride.

Watch your horse’s weight and condition through any change. Our guide to body condition scoring shows how to track it by eye.

What are hindgut ulcer symptoms?

Nobody can give you a reliable list. You will hear “hindgut ulcers” talked about a lot, but the research is far thinner than for the stomach, and there is no simple test like the gastroscope.

The best described condition is right dorsal colitis, ulceration and inflammation in one section of the large colon. It is usually linked to anti-inflammatory drugs such as bute. In a study of 35 cases from seven Australian equine hospitals, an overdose of anti-inflammatories was found in 84% of cases where the dose was known. The common signs were diarrhoea, colic and a raised heart rate, and most horses had low protein on blood tests. It was serious: 43% did not survive.

The authors note the signs are vague and look like other gut diseases. A horse with ongoing loose droppings, weight loss and grumbling colic needs a vet’s work-up with bloods and ultrasound, not a hindgut supplement.

When should you call the vet about ulcers?

Book a visit, and mention ulcers so your vet can plan whether to scope, if your horse has:

• Become girthy, resistant or less willing under saddle with no obvious cause
• Gone off its hard feed or become a picky eater
• Lost weight or condition on the same diet
• Had more than one bout of mild colic, especially around feeding

Call the vet straight away for colic that doesn’t settle, a horse that is rolling or repeatedly lying down, diarrhoea in a horse that is dull or off its food, or any horse that won’t eat at all. Those are emergencies whatever the cause.

Where the technology fits

Stride cannot tell you whether your horse has ulcers. Nothing in the app diagnoses them, scores the risk, or suggests a treatment. That takes a vet and a scope.

What it can do is keep the record your vet will ask about, so you are not relying on memory:

• Observations. You can log what you noticed on a given day, and several at once. The list includes Girthy, Off food, Signs of colic, Reluctant to work and Loose droppings, with an optional strength (mild, moderate or marked) and a note. They show on the horse’s health timeline, so a pattern over weeks is easy to see.
• Ride logging. Each ride can carry an effort rating from 1 to 10 and a “How did the horse go?” choice, including Nappy / reluctant, Tense / tight and Felt off.
• Vet records take a type, a status and notes, and you can attach photos or PDFs, so the gastroscopy report and any recheck sit with the horse.
• The feed log has types for Hay / forage, Chaff / fibre and Hard feed, with the amount and unit, and holds sugar and starch percentages from a feed label. It flags feeds over 12% sugar and starch combined. It does not track the gaps between feeds, so it won’t warn you about a six hour stretch with nothing to eat.
• Reminders can be set for a vet appointment, so the recheck scope doesn’t slip.

It is a diary, not a diagnosis.

If you take one thing from this: when your horse starts saying no under saddle, don’t settle on ulcers or rule them out on a hunch. Write down what you’re seeing and when, give a scoop of chaff before every ride from today, and ask your vet to look at the whole horse, back, legs, saddle and stomach.