What are some of the common signs that your horse is affected by ulcers? If your horse is losing weight, not eating well, or has developed a coarse coat they may be affected by ulcers.

But these are not the only symptoms that you should be on the lookout for. Every horse owner should be aware of these signs because Equine Gastric Ulcer Syndrome (EGUS) is one of the most common medical conditions in horses.

Researchers estimate that 60-90% of performance horses will develop EGUS at some point. Pleasure horses and foals can also develop ulcers, although the disease is somewhat different.

Domesticated horses are prone to ulcers because of their biology and how we feed and manage them. Horses evolved to spend up to 16 hours a day grazing grass and forages. Their stomach produces acid continuously regardless of whether there is feed in the stomach. [1]

As a horse grazes, a continuous flow of saliva helps to neutralize stomach acid, keeping the pH level at four or greater for most of the day. [1] However, problems can occur when a horse has limited access to forage and this acid attacks the lining of the stomach and gut.

The high grain diets often fed to performance horses lead to the production of volatile fatty acids (VFAs). This can further contribute to ulcer development, as VFAs can damage cells of the stomach. [2]

In addition, stress is a major risk factor for ulcers. Physical and environmental stressors such as intense exercise, stall confinement, and transport stress are common in performance horses and increase the risk of EGUS.

Social stressors, such as changes in the herd group or changes to the environment and routine, can cause stress in the horse.


Quiz: Assess Your Horse's Ulcer Risk

Signs that your Horse might have Ulcers

Symptoms of EGUS are often subtle and not specific to ulcers. Although most horses show some signs of gastric ulceration, over half of horses with ulcers don’t show any symptoms at all. [4]

With that said, there are a number of specific symptoms that have been directly linked with EGUS. If your horse shows any of the following signs, you should have him or her evaluated by your veterinarian who can perform an endoscopy to look for ulcers in the stomach and small intestine.

1. Poor Appetite

One of the most common signs of ulcers is the reluctance to finish meals or being a “picky eater”. This is likely a direct result of ongoing abdominal discomfort.

Your horse may start eating his grain ration but then back off. He might also show less interest in eating altogether. Some horses may be fussy about eating hay as well as grain or concentrates.

2. Weight Loss

Loss of appetite goes hand in hand with weight loss, which can occur over time if your horse is not finishing his meals. However, weight loss may also occur from a decreased absorption of nutrients which is linked with more severe cases of EGUS. Nutrient malabsorption happens when the lining of the stomach or small intestine has been damaged.

3. Poor Body Condition

When a horse loses weight due to a lack of appetite and/or malabsorption of nutrients, this can lead to a poor body condition. Your horse may lose muscle over the top line, neck, or hindquarters. You may see more prominent ribs and your horse may have a generally unthrifty appearance.

According to the Henneke body condition scoring system, a horse with a score of 4 or less is considered underweight. If your horse’s body condition declines over a matter of months and the feeding regimen hasn’t changed, having him evaluated by your veterinarian is a good idea.

4. Poor Coat Condition

If your horse has lost some of his usual shine or has developed a coarse coat, this may also be a sign of ulcers. A horse’s coat condition is related to his diet and also to the health of the entire digestive system. Problems on the inside can definitely be reflected on the outside.

A high parasite load and mineral imbalances can also lead to poor coat condition and should be ruled out. The  most common mineral imbalances to affect coat quality are low copper and zinc due to high iron intake.

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5. Chronic Diarrhea

Horses can have an episode of diarrhea when they are nervous or due to a sudden change in diet. They can also develop diarrhea with certain illnesses such as salmonellosis or coronavirus. However, chronic diarrhea may be a symptom of ulcers.

Researchers aren’t sure exactly why this occurs, but it has been reported widely enough that it is accepted as one of the clinical signs of ulcers in horses. [2]

6. Recurrent Colic

On the opposite end of the spectrum, some horses with EGUS can develop recurrent (often mild) colic. In one study, 83% of horses with recurring colic were found to have gastric ulcers. Researchers directly linked ulcers to colic in 28% of those horses (as documented by the response to an acid-suppressive treatment). [1]

Again, researchers aren’t sure exactly why colic occurs with ulcers. However, it’s thought that horses with EGUS may have altered gastrointestinal motility which can then increase their chances of experiencing colic. [2]

7. Behavioral Changes

When your horse isn’t feeling well, he may display behavior that he may not otherwise show. Any behavioral change in your horse should be cause for concern and warrants further investigation.

Horses with ulcers may act more aggressively toward other horses, especially at feeding time. A horse with ulcers may rush the feed bucket, paw, threaten neighboring horses, or kick at the walls of his stall. He may also seem nervous or spooky under saddle or just generally appear grumpy with herd mates or handlers.

8. Sensitivity in the Girth Area

If your horse is fussy when the girth is tightened, don’t assume he’s just being difficult or doesn’t want to be ridden. Girthiness is also a sign of ulcers in horses. Though some might think that the stomach is located in the girth area, it is actually the hindgut (specifically the colon) that extends up the length of the underside of the belly, all the way into the girth area.

In one study, 92% of horses with “girthiness” were found to have gastric ulcers. [6]

9. Stretching as if to Urinate

A horse suffering from EGUS may frequently stretch out like he needs to urinate. This behavior is likely an attempt to relieve discomfort in the abdominal region and is easy to recognize.

It should be noted that horses may also stretch out like this if they are experiencing gas colic. But if your horse displays this behavior on a frequent basis, it could very well be ulcers.

10. Cribbing or other Stereotypic Behaviors

Stereotypic behaviors, such as cribbing, are repetitive and unnatural behaviors that become increasingly fixed. However, these behaviors only occur in a small percentage horses so this is one of the less common signs of ulcers.

Dietary factors such as a lack of available forage have been strongly associated with oral stereotypies like cribbing. However, foals with ulcers may crib-bite as well. [7]

11. Teeth Grinding

A horse may grind his teeth for several reasons, including anxiety and other painful conditions. However, this behavior also appears to be a common sign of gastric ulcers, especially in foals.

Foals can develop ulcers from sudden weaning practices combined with the feeding of concentrates and bruxism is often a telltale sign of the condition.

12. Excessive Salivation

Did you know that a horse’s salivary glands normally produce almost 40 liters (10 gallons) of saliva per day? This happens in order to moisten food in preparation for its journey through the digestive system. Excessive salivation, or drooling, is never normal in horses though and should always be a cause for concern.

Excessive salivation can be a sign of ulcers in the horse’s mouth, esophagus, or stomach. This symptom also seems to be common in foals with severe ulceration. [1]

13. Excessive Recumbency

Horses can sleep standing up, but they do need to lay down (referred to as recumbency) for several hours each day to reach full REM sleep. However, if you notice your horse laying down more than usual, this could indicate a medical issue, including ulcers.

14. Poor Performance

Researchers have found a significant association between poor performance in Thoroughbred race horses and EGUS. [1]

During intense exercise there is an increase in abdominal pressure that causes the stomach to compress. This pushes acid from the bottom glandular region to nonglandular region, putting it in direct contact with intestinal cells that lack natural defenses to neutralize the acid.

Ulcers in the nonglandular region of the horse’s stomach are similar to lesions that cause heart burn or gastric reflux disease (GERD) in human athletes who complain of upper GI pain during exercise.

Researchers believe the link between poor performance in horses and ulcers might also be the result of gastric pain.

There are many different clinical signs of gastric ulcers, and your horse may show many of these or only one. It is not known why some horses show many symptoms while others have minimal symptoms beyond not performing well or having a dull coat. The symptoms listed above can also suggest other diseases or nutritional deficiencies.

Types of Ulcers in Horses

A horse with EGUS can develop ulcers in four main parts of the digestive system:

  • Lower part of the esophagus
  • Nonglandular region of the stomach
  • Glandular region of the stomach
  • Upper small intestine

The glandular region of the stomach produces acid but also produces natural defences such as mucous and bicarbonate to buffer the acid and protect the cells in that region. In contrast, the nonglandular “squamous” region is not pro