Gastric Ulcers in Racing Horses: Why Nearly All of Them Have It

Equine gastric ulcer syndrome is the most common medical condition in racing horses, and the most consistently under-diagnosed. Survey prevalence in horses in active race training runs from 80% to over 90% depending on the population.

Why the horse is built for trouble

The equine stomach secretes acid continuously, whether or not there is feed in it. That works when the animal is grazing for sixteen hours a day, because saliva — produced by chewing, not by anticipation — is the buffer, and forage forms a fibrous mat that keeps acid away from the unprotected squamous mucosa in the upper third of the stomach.

Race training removes every part of that arrangement:

• Concentrate feeding requires far less chewing per calorie, so less saliva
• Restricted forage removes the fibrous mat
• Meal feeding leaves long empty periods with acid still being produced
• Exercise compresses the abdomen and splashes acid up onto the squamous mucosa
• Stall confinement and transport are independent risk factors in every study that has looked

The disease is management-induced. That is inconvenient, but it is also the reason it responds to management change.

Recognising it

The classic signs are unreliable, which is why the condition is missed:

• Reduced appetite, particularly leaving the last of a feed
• Poor coat and loss of condition despite adequate ration
• Behaviour change — girthiness, resistance, a horse that has become sour
• Reduced performance without lameness
• Mild recurrent colic
• Teeth grinding, especially in younger animals

Many affected horses show none of these. Gastroscopy is the only definitive diagnosis, and a yard that scopes routinely finds a great deal it was not looking for.

Treatment

Omeprazole at a healing dose, given for the full course, is the only therapy with a substantial evidence base for squamous ulceration. The points that determine whether it works:

Dose. The healing dose and the maintenance dose are different. Using a maintenance dose to heal an active ulcer wastes the money and the month.

Duration. Twenty-eight days, and re-scope at the end. Stopping when the horse seems better is the most common reason a course fails.

Timing. Omeprazole absorbs best on a relatively empty stomach. Given in the middle of a large feed it substantially under-performs.

Tapering. Abrupt withdrawal after a long course produces rebound acid hypersecretion. Step down rather than stop.

Glandular disease — ulceration in the lower stomach — behaves differently, often responds poorly to omeprazole alone, and needs a veterinary plan of its own.

Preventing the relapse

Treatment without management change buys you a few weeks. The changes that hold:

1. Forage before exercise. A small forage feed within an hour of work gives the acid something to sit in.
2. Free-choice forage where the ration allows it. Even a slow-feeder net changes the picture.
3. Split the concentrates into more, smaller meals.
4. Alfalfa in the ration — it buffers well, largely through its calcium content.
5. Turnout wherever it can be arranged.
6. Minimise NSAID courses, and where one is necessary, cover it.
7. Reduce transport stress — travel less, travel better, and feed forage in transit.

A horse that scopes clean at the end of a 28-day course and goes back into exactly the same routine will be ulcerated again within weeks. The scope tells you the treatment worked. It says nothing about whether the cause was addressed.

Omeprazole is prescription-tier, permitted under most rulebooks with declaration, and carries a short detection time. Confirm your own authority's position and treat under veterinary direction.