Association between long periods without high-speed workouts and risk of complete humeral or pelvic fracture in thoroughbred racehorses: 54 cases (1991-1994).
Abstract: To determine whether a two-month or longer period without official high-speed workouts (lay-up) is associated with humeral or pelvic fracture in Thoroughbred racehorses. Methods: Reprospective study. Methods: Thoroughbred racehorses in California that were euthanatized because of a complete humeral or pelvic fracture. Methods: Age, sex, activity, number of lay-ups, number of days from a race or official timed workout to fracture, number of days from end of last lay-up to fracture, mean duration of lay-ups, and total number of days in race training were compared between horses with humeral fractures and horses with pelvic fractures. A case-crossover study was used to estimate relative risk for fracture of the humerus or pelvis occurring within hazard periods of 10 and 21 days following lay-up, compared with periods following more regular participation in official racing or timed workout events. Results: Horses with pelvic fractures were more often female, older, and had 0 or > or = 2 lay-ups. Horses with humeral fractures were typically 3-year-old males that had 1 lay-up. Horses with pelvic fractures had more total days in race training, fewer days from last exercise event to fracture, and a greater number of days from end of last lay-up to fracture than horses with humeral fractures. Return from lay-up was strongly associated with risk for humeral fracture during hazard periods of 10 and 21 days (relative risk = 71 and 45, respectively). Conclusions: Risk of humeral fracture may be reduced if horses are cautiously reintroduced into race training after lay-up.
Publication Date: 1998-05-30 PubMed ID: 9604029
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study aims to investigate if long periods without official high-speed workouts (termed as ‘lay-ups’) influences the risk of developing fatal humeral or pelvic fractures in Thoroughbred racehorses.
Research Methodology
- The study employs a retrospective methodology, referring to past records and data.
- The subjects of the research are Thoroughbred racehorses in California that were euthanized due to complete humeral or pelvic fractures.
- Various factors were considered, including age, sex, activity, number and duration of lay-ups, number of days from a race or timed workout to fracture, number of days from the end of last lay-up to fracture, and total number of days in race training.
- These factors were compared between horses with different types of fractures: humeral and pelvic.
- The researchers used a case-crossover study to estimate the relative risk for fractures, occurring within specific ‘[hazard] periods’ of 10 and 21 days after lay-up, compared to periods following regular participation in racing or timed workout events.
Findings of the Study
- The study found that horses with pelvic fractures tended to be older females that either had no lay-ups or two and more lay-ups.
- On the other hand, horses with humeral fractures were often 3-year-old males that had a single lay-up.
- Pelvic fracture cases showed more total days in race training, fewer days between the last exercise event to fracture, and more days from the end of the last lay-up to the fracture than horses with humeral fractures.
- The return from lay-up was found to be significantly associated with the risk of humeral fractures during the 10 and 21-day hazard periods (relative risks were 71 and 45, respectively).
Conclusion
Based on the results, the study suggests that the risk of humeral fractures in Thoroughbred racehorses may be reduced if horses are carefully reintroduced to race training following a lay-up. This implies a need for regulating and monitoring the intensity and frequency of training regimes immediately after a lay-up period.
Cite This Article
APA
Carrier TK, Estberg L, Stover SM, Gardner IA, Johnson BJ, Read DH, Ardans AA.
(1998).
Association between long periods without high-speed workouts and risk of complete humeral or pelvic fracture in thoroughbred racehorses: 54 cases (1991-1994).
J Am Vet Med Assoc, 212(10), 1582-1587.
Publication
Researcher Affiliations
- J. D. Wheat Orthopedic Research Laboratory, Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616-8732, USA.
MeSH Terms
- Animals
- Case-Control Studies
- Confidence Intervals
- Cross-Over Studies
- Female
- Hip Fractures / etiology
- Hip Fractures / veterinary
- Horses / injuries
- Horses / physiology
- Humeral Fractures / etiology
- Humeral Fractures / veterinary
- Male
- Pelvic Bones / injuries
- Physical Conditioning, Animal / physiology
- Retrospective Studies
- Risk
- Risk Factors
- Time Factors
Citations
This article has been cited 16 times.- Legg KA, Gee EK, Breheny M, Gibson MJ, Rogers CW. A Bioeconomic Model for the Thoroughbred Racing Industry-Optimisation of the Production Cycle with a Horse Centric Welfare Perspective. Animals (Basel) 2023 Jan 30;13(3).
- Shaffer SK, Stover SM, Fyhrie DP. Training drives turnover rates in racehorse proximal sesamoid bones. Sci Rep 2023 Jan 27;13(1):205.
- Crawford KL, Finnane A, Greer RM, Barnes TS, Phillips CJC, Woldeyohannes SM, Bishop EL, Perkins NR, Ahern BJ. Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia. Front Vet Sci 2021;8:698298.
- Legg KA, Gee EK, Cochrane DJ, Rogers CW. Preliminary Examination of the Biological and Industry Constraints on the Structure and Pattern of Thoroughbred Racing in New Zealand over Thirteen Seasons: 2005/06-2017/18. Animals (Basel) 2021 Sep 27;11(10).
- Crawford KL, Finnane A, Greer RM, Phillips CJC, Bishop EL, Woldeyohannes SM, Perkins NR, Ahern BJ. A Prospective Study of Training Methods for Two-Year-Old Thoroughbred Racehorses in Queensland, Australia, and Analysis of the Differences in Training Methods between Trainers of Varying Stable Sizes. Animals (Basel) 2021 Mar 25;11(4).
- Crawford KL, Finnane A, Phillips CJC, Greer RM, Woldeyohannes SM, Perkins NR, Kidd LJ, Ahern BJ. The Risk Factors for Musculoskeletal Injuries in Thoroughbred Racehorses in Queensland, Australia: How These Vary for Two-Year-Old and Older Horses and with Type of Injury. Animals (Basel) 2021 Jan 21;11(2).
- Crawford KL, Finnane A, Greer RM, Phillips CJC, Woldeyohannes SM, Perkins NR, Ahern BJ. Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence, Risk Factors and Outcomes for Horses after Retirement from Racing. Animals (Basel) 2021 Jan 11;11(1).
- Rosanowski SM, Chang YM, Stirk AJ, Verheyen KLP. Risk factors for race-day fatality in flat racing Thoroughbreds in Great Britain (2000 to 2013). PLoS One 2018;13(3):e0194299.
- Maeda Y, Hanada M, Oikawa MA. Epidemiology of racing injuries in Thoroughbred racehorses with special reference to bone fractures: Japanese experience from the 1980s to 2000s. J Equine Sci 2016;27(3):81-97.
- Firth EC. The response of bone, articular cartilage and tendon to exercise in the horse. J Anat 2006 Apr;208(4):513-26.
- Mitchell C, Riley CB. Evaluation and treatment of an adult quarter horse with an unusual fracture of the humerus and septic arthritis. Can Vet J 2002 Feb;43(2):120-2.
- Schild CO, Nyaoke A, Asin J, Henderson EE, Blea JA, Stover SM, Uzal FA. A retrospective study of radial fractures in racehorses in California, 2006-2022. J Vet Diagn Invest 2025 Jul 23;:10406387251336267.
- Morrice-West AV, Thomas M, Wong ASM, Flash M, Whitton RC, Hitchens PL. Linkage of jockey falls and injuries with racehorse injuries and fatalities in Thoroughbred flat racing in Victoria, Australia. Front Vet Sci 2024;11:1481016.
- Bogossian PM, Nattala U, Wong ASM, Morrice-West AV, Zhang GZ, Rana P, Whitton RC, Hitchens PL. A machine learning approach to identify stride characteristics predictive of musculoskeletal injury, enforced rest and retirement in Thoroughbred racehorses. Sci Rep 2024 Nov 22;14(1):28967.
- Costa da Silva RG, Sun TC, Mishra AP, Boyde A, Doube M, Riggs CM. Intracortical remodelling increases in highly loaded bone after exercise cessation. J Anat 2024 Mar;244(3):424-437.
- Wong ASM, Morrice-West AV, Hitchens PL, Whitton RC. The association between Thoroughbred racehorse training practices and musculoskeletal injuries in Victoria, Australia. Front Vet Sci 2023;10:1260554.
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