Objective—To determine racing performance after surgery for colic in Thoroughbreds.
Design—Retrospective cohort study.
Animals—85 racing Thoroughbreds that survived to discharge following colic surgery and 170 race-matched reference horses.
Procedures—Earnings, starts, and earnings per start were compared between horses that underwent surgery and reference horses, the proportions of horses that returned to racing were analyzed, and career longevity was determined.
Results—Among 85 racing Thoroughbreds that underwent colic surgery, 31 (36%) had primarily small intestinal lesions, of which 11 underwent resection; 54 (64%) had large intestinal lesions, of which 2 underwent resection. Fifty-nine of 85 (69%) horses that underwent colic surgery returned to racing after a 6-month recovery period versus 125 of 170 (73%) reference horses (OR, 0.81). In the 36-month postoperative period, reference horses earned a mean of $7,866 more, had a mean of 0.26 more starts, and had mean earnings per start of $29 more than horses that underwent surgery. Horses that underwent surgery did not have different career lengths than reference horses.
Conclusions and Clinical Relevance—Horses that underwent colic surgery did not have a significant reduction in measures of performance or career length, compared with a reference cohort.
OBJECTIVE To determine the anabolic and lipolytic effects of a low dosage of clenbuterol administered orally in working and nonworking equids.
ANIMALS 8 nonworking horses and 47 polo ponies in active training.
PROCEDURES Each polo pony continued training and received either clenbuterol (0.8 μg/kg) or an equal volume of corn syrup (placebo) orally twice daily for 21 days, and then was evaluated for another 21-day period. Nonworking horses received clenbuterol or placebo at the same dosage for 21 days in a crossover trial (2 treatments/horse). For working and nonworking horses, percentage body fat (PBF) was estimated before treatment and then 2 and 3 times/wk, respectively. Body weight was measured at intervals.
RESULTS Full data sets were not available for 8 working horses. For working horses, a significant treatment effect of clenbuterol was detected by day 3 and continued through the last day of treatment; at day 21, the mean change in PBF from baseline following clenbuterol or placebo treatment was −0.80% (representing a 12% decrease in PBF) and −0.32%, respectively. By day 32 through 42 (without treatment), PBF change did not differ between groups. When treated with clenbuterol, the nonworking horses had a similar mean change in PBF from baseline from day 6 onward, which peaked at −0.75% on day 18 (an 8% decrease in PBF). Time and treatment had no significant effect on body weight in either experiment.
CONCLUSIONS AND CLINICAL RELEVANCE Among the study equids, long-term low-dose clenbuterol administration resulted in significant decreases in body fat with no loss in body weight.