Equine Gastric Ulcer Syndrome

by Philip van Harreveld, DVM, MS

Gastric ulcers disease is a common condition in foals and horses. Prevalence estimates have been reported to range from 25-50% in foals and 60 to 90% of adult horses, depending on age performance, and evaluated populations. Although ulcers are similar in foals and horses, they might present with different clinical signs. A diagnosis of this disease relies on the recognition of clinical signs and endoscopic examination of the stomach.

It is important to point out that 50% of horses with ulcers show no outward signs of gastrointestinal disease, but ulceration can interfere with performance by affecting training, appetite, and temperament. Ulcers may heal naturally if horses are turned out to pasture for an extended period of time, but they usually don't heal in horses that continue training.

The picture on the left is a normal stomach and the picture on the right is a stomach affected with ulcers. (Endoscopic views)

How do ulcers form?

The equine stomach secretes acid continuously. Lesions in the upper portion of the equine stomach (the squamous mucosa lining) result primarily from excessive acidity, whereas lesions that affect the bottom of the stomach (the gastric glandular mucosa lining) result primarily from defective mucosal protection. Like human ulcers, stomach acid appears to be the main cause of equine ulcers. Excess acid can eat through the protective lining and damage the stomach. The high prevalence of ulcers seen in performance horses results from many factors including the way the horses are fed and managed. Intensity of training also may contribute to ulcer formation, but the exact reason why remains undetermined. Helicobacter pylori, bacteria that are a factor in the development of human ulcers, have not been isolated from horse stomachs and are currently not considered to be a cause of horse ulcers.

Diagnosis: is based on the presence of clinical signs and confirmation with endoscopic examination. Clinical signs in foals include intermittent colic, laying on it's back, diarrhea, poor appetite, teeth grinding, and excessive salivation. In adult horses clinical sings include poor appetite, failure to consume a meal, dullness, attitude changes, decreased performance, reluctance to train, poor body condition, rough hair coat, weight loss, excessive laying down, and low grade colic. A definite diagnosis can only be made with an endoscope.

Treatment: Inhibiting gastric acid secretion is the mainstay of gastric ulcer treatment in horses. A number of treatment modalities have been used for treatment and prevention of gastric ulcers in horses and foals. Currently, there is only one FDA approved treatment for gastric ulcers, Gastrogard. However, many treatments modalities have been described in the literature.