FACTORS ASSOCIATED WITH GASTRIC-LESIONS IN THOROUGHBRED RACEHORSES

Gastroscopic examinations were performed on 67 Thoroughbred horses in training at a race track and repeat examinations performed in 35 horse s, 2 to 3 months later. Horses were age 2-9 years and included 16 two- year-olds, 32 three-year-olds and 19 horses greater than or equal to 4 -years-old. Forty-two of the 67 horses had raced within the 2 months b efore the initial examination and the remaining 25 horses were in trai ning. Sixty-two of the 67 horses (93%) had one or more lesions present in the gastric mucosa and lesions were present in all of the 32 horse s that had raced. Thirty-two of the 35 horses, examined twice (91%), h ad gastric lesions on the first examination and all had lesions on the second examination. Four sites of the gastric squamous epithelium wer e graded for lesion severity on a scale of 0 to 10 and the mean maximu m squamous mucosal lesion score was significantly (P<0.01) greater for the second examination (4.89) than for the first examination (3.63). Maximum lesion scores were greater in 24 horses, no different in 5 hor ses and less in 6 horses on the second examination. The difference in mean maximum lesion scores between examinations was greatest in horses age 2 years, increasing from 1.75 to 4.00 (P = 0.014), Lesions in the gastric glandular mucosa also were scored on a scale of 0 to 10 and t here was no difference in mean lesion scores in the glandular mucosa b etween the first and second examinations (1.89 vs. 1.90). Lesion score s were compared for gender, racing history and medication with nonster oidal anti-inflammatory drugs, systemic corticosteroid or ACTH, or fru semide within the previous 2 months, Except for racing history, there were no significant differences in mean lesion scores for squamous or glandular mucosa based on these comparisons, indicating that there was no effect of gender or medication history on ulcer severity in the ho rses of our study. Mean maximum gastric squamous mucosal lesion score was significantly (P<0.01) greater in horses that had raced (4.51) tha n for horses that had not raced (2.36) in the 2 months before the endo scopic examination. There was no difference in mean glandular mucosal lesion scores between horses that had raced (1.93) compared to horses that had not raced (1.13).