Odds of moderate or severe gastric ulceration in racehorses receiving antiulcer medications.

OBJECTIVE: To determine the odds of moderate or severe gastric ulceration in racehorses treated with various antiulcer medications. DESIGN: Unmatched case-control study. ANIMALS: 798 horses in active race training (252 Thoroughbreds and 546 Standardbreds). Only horses that had been receiving a single antiulcer medication or no antiulcer medication for at least 2 weeks prior to examination were included. PROCEDURE: Gastroscopy was performed on each horse by a single individual who was not aware of the horses' antiulcer treatments, and severity of gastric ulceration was scored. Signalment and medication history were recorded. Logistic regression was used to determine whether identification of moderate or severe ulceration was associated with treatment, age, breed, or sex. Treatments were grouped as no treatment, buffer, sucralfate, histamine type 2 receptor antagonist, compounded omeprazole, proprietary omeprazole at a low dosage, and proprietary omeprazole at a high dosage. RESULTS: Only proprietary omeprazole was associated with significantly lower odds of moderate or severe ulceration, compared with no treatment. Risks of moderate or severe gastric ulceration in horses receiving a buffer, sucralfate, a histamine type 2 receptor antagonist, or compounded omeprazole were not significantly different from risks in horses receiving no antiulcer medication. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the proprietary formulation of omeprazole was associated with a significantly lower risk of moderate or severe gastric ulceration, compared with no treatment, in racehorses in active race training, whereas other antiulcer medications were not.

Associations between age or sex and prevalence of gastric ulceration in Standardbred racehorses in training.

OBJECTIVE: To determine associations between age, sex, or medical treatment and prevalence and severity of gastric ulceration in Standardbred racehorses in training. DESIGN: Cross-sectional study. ANIMALS: 224 Standardbred racehorses in training. PROCEDURE: Gastroscopy was performed on each horse, and mucosal ulceration was graded from 0 (normal mucosa, no lesions) to 3 (extensive, often coalescing, lesions with areas of deep ulceration). Associations between age, sex, or treatment and prevalence and severity of ulcers were evaluated. RESULTS: Prevalence of gastric ulceration was 87%. Although there was little association between age and prevalence of ulcers, there was an association between age and severity of ulcers. Most 2-year-old horses (57.7%) had an ulcer score of 0 or 1. In all other age groups, most (58% to 82.61%) of horses had an ulcer score of 2 or 3. Although overall prevalence of ulceration was comparable among sex groups, the relative risk for gastric ulceration increased with age in castrated males, whereas it decreased in females and sexually intact males. CONCLUSIONS AND CLINICAL RELEVANCE: Gastric ulceration is common in Standardbred horses in race training. Severity is higher in horses > or = 3 years of age than in 2-year-old horses. Relative risk for ulceration increases with age in castrated males.