Gastric Ulceration in Adult Horses

If you've ever had gastric ulcers or even just bad heartburn, you can sympathize with your horse when he has one of the most common health problems of the stabled horse – gastric ulceration. We humans have the luxury of a quick trip to the drug store for our favorite heartburn remedy, and we can call our physicians for a more in-depth diagnosis of why we experience such agonizing gastrointestinal pain. But horses can only show us by indirect signs that they are in chronic, debilitating pain. How can you understand the signals that your horse is sending you, and understand why he is sending you those signals?

Gastric ulceration in any species refers to an erosion, or sloughing, of one or multiple areas of the surface layer of the stomach. Gastric ulceration is common in horses – in various studies, from 70 percent to 100 percent of horses examined had endoscopic evidence of gastric ulceration. This, however, does not mean that all of these horses had clinical signs of gastric ulceration.

Unlike people, who can develop gastric ulcers in response to a bacterial infection, no infectious cause of gastric ulceration has been identified in horses. In fact, few specific causes of gastric ulceration have been clearly identified. However, most practitioners recognize that stress seems to precipitate gastric ulceration in foals; and infrequent feeds of low-roughage, high carbohydrate foods and a high level of training have been implicated in adult horses.

Unlike humans, horses secrete gastric acid continuously, whether they are eating or not. In the wild, horses spend the majority of their days continually eating small amounts of relatively poor quality, high roughage food. Continual acid secretion accommodates this natural lifestyle perfectly. When horses are fed large quantities of high quality food infrequently, their stomachs empty rapidly, essentially leaving the stomach with nothing to do.

The stomach has a variety of protectant factors against the effects of gastric acid, but when the stomach is empty, the horse's ability to withstand the effects of gastric acid can be overwhelmed. If gastric ulceration becomes severe, the erosions may begin to bleed. Horses can eventually become anemic and low in protein due to losses through the gastric ulcers.

The use of certain anti-inflammatory drugs (such as phenylbutazone ('Bute') or flunixin meglumine (Banamine™) can also induce gastric ulcers in horses.

What to Watch For


Your veterinarian will take a thorough history to try to identify any risk factors that may have contributed to your horse developing gastric ulceration. In addition, the following may also be necessary:


If your horse has gastric ulceration, your veterinarian will choose to treat with one of a variety of drugs that decrease the acidity of the stomach. He or she will be able to make dietary and training recommendations.

Home Care

It is important to follow all the instructions given by your veterinarian concerning length and frequency of administration of drugs. Make sure that your horse actually consumes the medications recommended by your veterinarian; it won't help if medications are left in a little pile in the bottom of the feed tub. For some picky eaters, it may be necessary to mix the medication with molasses or applesauce, and syringe it into the mouth.

It is important to monitor your horse's appetite, manure production, and attitude. Most horses will require a high roughage diet and plenty of turnout for best resolution of gastric ulceration.

Preventative Care

Horses that have constant access to turnout and roughage in the form of hay or pasture, and horses that are not in training, rarely develop gastric ulceration.

Probably, the best prevention for gastric ulceration is to mimic, as best as possible, the life of a horse at free range. This translates into frequent small meals, a preponderance of roughage in the diet, and plenty of turnout.

Gastric ulceration in horses occurs when acid production overwhelms the protective factors. Unlike the situation in humans, there is no evidence at this point that there is a bacterial cause of gastric ulceration in horses.

Acid production may overwhelm the stomach for various reasons, including:

How do NSAIDs cause gastric ulceration?

What are the signs of gastric ulceration in the horse?

Signs of gastric ulceration can be quite hard to pinpoint in horses. Imagine if you couldn't use words to describe how you feel when you have heartburn – you would have to use body language to try to explain the problem. That body language might include lying down more frequently because you're in pain, but then you'd get up again because lying down can make the pain worse. You wouldn't want to eat the foods that you previously enjoyed (even though that might have been a cheeseburger and fries!). You might start to eat, and then stop, because eating makes the pain worse. If you stopped eating the things that are good for you, you might start to lose the gloss in you hair, or become too thin, because you are no longer getting the nutrients that you need. If the pain became intense, you might groan, and hold your abdomen. Well, horses do many of these things, and more.

The most common signs of gastric ulceration in horses include:

The goal of treatment is to decrease the level of acidity in the stomach in order to allow the horse's natural healing processes to mend the ulcers. There are several ways to achieve this goal: all of them center around addressing the situation that allowed your horse to develop gastric ulceration in the first place. The way that you and your veterinarian choose to treat gastric ulceration will usually depend on your schedule as well as your ability to change your horse's environment.


Most horses do require some drug therapy in order to successfully treat gastric ulcers. Drugs designed to treat gastric ulcers may decrease the amount of acid produced by the stomach, physically coat the stomach to prevent the acid from wreaking havoc or buffer the acid in the stomach.

Drugs that decrease the amount of acid produced by the stomach

Drugs that buffer acid