Gastric Ulceration in Adult Horses
Basic Information 
Epidemiology
Species, Age, Sex
Most common in race horses (estimated >90% prevalence) and performance horses in active training
Clinical Presentation
History, Chief Complaint
• Colic: Usually mild and often associated with feeding
• Weight loss may be noted if chronic or severe
• Behavior or performance issues are often presumptively or anecdotally associated but are not consistent findings. These may include:
• Many adult horses have no clinical signs even with severe gastric ulceration.
Physical Exam Findings
• Usually within normal limits unless the patient has a concurrent predisposing disease.
• Moderately poor body condition and rough hair coat are sometimes present in severe cases. Marked weight loss in a horse that is diagnosed with gastric ulceration suggests concurrent predisposing disease such as IBD and warrants further diagnostic investigation for such a cause.
• Rectal examination: Usually normal unless ulceration is secondary to other GI disease such as IBD, a chronic or recurrent colonic displacement, or other partial intestinal obstruction.
Etiology and Pathophysiology
• Hydrochloric acid is continuously secreted by the parietal cells in the gastric glandular epithelium.
• The gastric mucosa is typically protected from the extremely acidic gastric contents by several mechanisms, including:
• Anything that disrupts these innate protective mechanisms may result in gastric ulceration
High-concentrate diets, infrequent feeding and withholding of feed, and anorexia result in prolonged periods of low gastric pH, resulting in lesions in the poorly protected squamous mucosa.
• Bacterial causes of gastric ulceration (eg, Helicobacter pylori) have not been documented in horses.
