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Case–control study of high‐speed exercise history of T horoughbred and Q uarter H orse racehorses that died related to a complete scapular fracture
Author(s) -
Vallance S. A.,
Entwistle R. C.,
Hitchens P. L.,
Gardner I. A.,
Stover S. M.
Publication year - 2013
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.2012.00644.x
Subject(s) - medicine , confidence interval , odds ratio , logistic regression , physical therapy , demography , sociology
Summary Reasons for performing study: Identification of exercise history patterns that are related to catastrophic scapular fracture will facilitate prevention of racehorse fatalities. Objectives: To determine if exercise patterns are associated with scapular fracture in T horoughbred ( TB ) and Q uarter H orse ( QH ) racehorses. Methods: High‐speed exercise histories for 65 TB and 26 QH racehorses that had a complete scapular fracture (cases) and 2 matched control racehorses were retrospectively studied. Exercise variables were created from lifetime race and official timed workout reports. Associations between exercise variables and scapular fracture were investigated using conditional logistic regression. Results: Thoroughbreds with a scapular fracture had a greater number of workouts, events (combined works and races), and mean event distances than QH s with a scapular fracture. Quarter Horses worked less frequently and accumulated distance at a lower rate than TB s. Breed differences were not found for career race number or length, time between races or lay‐up variables for horses with ≥1 lay‐up. For both breeds, cases had fewer events, lower recent accumulated distance and fewer active days in training than controls; however, a subset of TB cases with >10 events since lay‐up had a longer active career than controls. For QH s that had a lay‐up, total and mean lay‐up times were greater for cases than controls. Multivariable models revealed that odds ratios ( OR ) of scapular fracture were greater for TB s that had not yet raced ( OR = 23.19; 95% confidence interval (CI) 3.03–177.38) and lower for QH s with more events ( OR = 0.71; 95% CI 0.54–0.94). Conclusions and clinical relevance: Racehorses that are in early high‐speed training but behind that of their training cohort should be examined for signs of scapular stress remodelling. Quarter Horses that had a prolonged lay‐up and TB s that have endured high‐speed training for a longer duration than that of their training cohort also were at greater risk.