Signs & Symptoms of Stomach Ulcers in Horses

Updated April 07, 2017

An ulcer is defined as internal damage to the stomach and stomach lining in a horse. This condition, referred to as Equine Gastric Ulcer Syndrome or EGUS, can be caused by many factors. Some causes of EGUS include no or infrequent grazing, changes in diet or infrequent feedings, extended use of drugs or medications such as Non Steroidal Anti-Inflammatories (NSAIDs), intense work or training, and stress. Equine Gastric Ulcer Syndrome may affect both personality and performance in a horse, and a diagnosis may be made by a veterinary professional by observation or by an endoscopic exam.


A formerly willing or docile horse who suddenly becomes sullen, nappy, or refuses work may be showing signs of pain from ulcers. A personality change for a performance horse might include an unwillingness to work forward, or even show signs of discomfort when being tacked up. A horse which suddenly becomes "girthy", meaning that when the saddle girth is tightened the horse lays his or her ears back, stamps, or bites, may be a sign that the horse is experiencing pain from EGUS.

Poor Appetite

As eating and grazing are a horse's primary daily activities, a horse which is suddenly uninterested in feed or hay may be exhibiting signs of ulcers. Eating affects the stomach acids which can cause ulcers, and can cause additional pain for a horse. A horse which is not eating or grazing may also be suffering from a bout of colic, so this symptom should be observed carefully as it can be a sign of life-threatening issues for a horse.

Recurrent Colic

A colic is an instance where the horse's intestinal tract ceases to function properly, either due to a physical blockage or stomach upset. Horses who colic frequently may also be affected by EGUS, as the upset in stomach chemistry can lead to an improperly functioning intestine, causing colic. Colic symptoms include signs of pain, no bowel movements, and kicking or pawing at the stomach area. As a colic can be dangerous and potentially life threatening, it is critical that this symptom is treated promptly.

Poor Condition

A loss of weight and condition due to disinterest in food and grazing can be a sign of EGUS. A horse with poor condition will often have a rough, dull coat. Their ribs and spine may become more prominent. These symptoms are caused by improper nutrition if a horse with EGUS does not ingest a balanced diet. As a horse becomes more underweight, the more likely the horse is to develop further issues such as infection or colic due to a lowered immune system.

Diarrhoea or Reduced Stool

Another sign of EGUS in horses is changes in the manure pattern. A horse's manure should be produced frequently, in semi-solid clumps. Horses suffering from EGUS may exhibit loose, watery stools or less frequent bowel movements. This is due to irritation in the stomach and intestines caused by EGUS. While these are symptoms of ulcers in horses, they should be treated as serious--a horse who is not producing manure or who is producing watery stools may colic or dehydrate if not treated promptly.

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About the Author

Gwen Wark is a freelance writer working from London, Dublin, and New York. She has been a published writer since 1998 with works appearing in both university and local publications. Her current writing projects include SEO, web copy, print and advertising features. She holds a Bachelor of Arts in English with a minor in history from Rutgers University.