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Frontiers in veterinary science2021; 8; 698298; doi: 10.3389/fvets.2021.698298

Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia.

Abstract: Musculoskeletal injuries remain a global problem for the Thoroughbred racing industry and there is conflicting evidence regarding the effect of age on the incidence of injuries. The ideal time to commence race training is strongly debated, with limited supporting literature. There is also conflicting evidence regarding the effect of high-speed exercise on musculoskeletal injuries. There is a strong interest in developing training and management strategies to reduce the frequency of injuries. The types of musculoskeletal injuries vary between 2-year-old and older horses, with dorsal metacarpal disease the most common injury in 2-year-old horses. It is likely that risk factors for injury in 2-year-old horses are different than those for older horses. It is also likely that the risk factors may vary between types of injury. This study aimed to determine the risk factors for musculoskeletal injuries and dorsal metacarpal disease. We report the findings of a large scale, prospective observational study of 2-year-old horses in Queensland, Australia. Data were collected weekly for 56-weeks, from 26 trainers, involving 535 2-year-old Thoroughbred racehorses, 1, 258 training preparations and 7, 512-weeks of exercise data. A causal approach was used to develop our statistical models, to build on the existing literature surrounding injury risk, by incorporating the previously established causal links into our analyses. Where previous data were not available, industry experts were consulted. Survival analyses were performed using Cox proportional hazards or Weibull regression models. Analysis of musculoskeletal injuries overall revealed the hazard was reduced with increased exposure to high-speed exercise [Hazard ratio (HR) 0.89, 95% Confidence Interval (CI) 0.84, 0.94, p < 0.001], increased number of training preparations (HR 0.58, 95% CI 0.50, 0.67, p < 0.001), increased rest before the training preparation (HR 0.89, 95% CI 0.83, 0.96, p = 0.003) and increased dam parity (HR 0.86, 95% CI 0.77, 0.97, p = 0.01). The hazard of injury was increased with increasing age that training commenced (HR 1.13, 95% CI 1.06, 1.19, p < 0.001). Analyses were then repeated with the outcome of interest dorsal metacarpal disease. Factors that were protective against dorsal metacarpal disease and musculoskeletal injuries overall included: increased total cumulative distance (HR 0.89, 95% CI 0.82, 0.97, p = 0.001) and total cumulative days exercised as a gallop (HR 0.96, 95% CI 0.92, 0.99, p = 0.03), the number of the training preparations (HR 0.43, 95% CI 0.30, 0.61, p < 0.001). The age that training commenced was harmful for both dorsal metacarpal disease (HR 1.17, 95% CI 1.07, 1.28, p < 0.001 and overall musculoskeletal injuries.). The use of non-ridden training modalities was protective for dorsal metacarpal disease (HR 0.89, 95% CI 0.81, 0.97, p = 0.008), but not musculoskeletal injuries overall. The male sex increased the hazard of DMD compared to females (HR 2.58, 95% CI 1.20, 5.56, p = 0.02), but not MSI overall. In summary, the hazard of musculoskeletal injury is greatest for 2-year-old horses that are born from uniparous mares, commence training at a later age, are in their first training preparation, have undertaken little high-speed exercise or had limited rest before their training preparation. The hazard of dorsal metacarpal disease is greatest for 2-year-old horses that are males, commence training at a later age, are in their first training preparation, have undertaken little high-speed exercise or had limited use of non-ridden training modalities. Close monitoring of these high-risk horses during their training program could substantially reduce the impact of MSI. Furthermore, an understanding of how training methodologies affect the hazard of MSI facilitates modification of training programs to mitigate the risk impact of injury. The strengths of this study include a large sample size, a well-defined study protocol and direct trainer interviews. The main limitation is the inherent susceptibility to survival bias.
Copyright © 2021 Crawford, Finnane, Greer, Barnes, Phillips, Woldeyohannes, Bishop, Perkins and Ahern.
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Publication Date: 2021-11-02 PubMed ID: 34796223PubMed Central: PMC8593238DOI: 10.3389/fvets.2021.698298Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research article focuses on identifying risk factors for musculoskeletal injuries and dorsal metacarpal disease in 2-year-old Thoroughbred racehorses in Queensland, Australia. It was found that the risk of injury decreases with increased exposure to high-speed exercise, more training preparations, greater rest periods before training, and increased dam parity, while the risk increases when training begins at a later age.

Study Design and Data Collection

  • The research was a large scale, prospective observational study of 2-year-old Thoroughbred racehorses in Queensland, Australia. The sample included 535 horses from 26 trainers.
  • Data were collected weekly for 56-weeks, tallying a total of 1,258 training preparations and 7,512-weeks of exercise data.
  • A causal approach was employed to develop statistical models, building upon existing literature surrounding injury risk and including the previously established causal links in the analyses. When no past data were available, industry experts were consulted.
  • Survival analyses were performed using Cox proportional hazards or Weibull regression models.

Key Findings

  • In general, the risk of musculoskeletal injuries decreases with increased exposure to high-speed exercise, larger number of training preparations, extensive rest before the training preparation, and higher dam parity.
  • Starting training at an older age increases the risk of injury.
  • Dorsal metacarpal disease (a common injury in 2-year-old horses) was better prevented by increased total cumulative distance and total cumulative days exercised at a gallop, more training preparations and the use of non-ridden training modalities.
  • Commencing training at an older age was harmful for both dorsal metacarpal disease and overall musculoskeletal injuries.
  • While the male sex showed an increased hazard for dorsal metacarpal disease compared to females, it did not lead to a notable increase in overall musculoskeletal injuries.

Implications and Limitations

  • The findings expose pressing risk factors for musculoskeletal injury in 2-year-old racehorses, providing a basis for monitoring high-risk horses during their training programmes and potentially reducing injury impacts.
  • The study may also guide modifications of training methodologies to lessen the risk of injury.
  • Strengths of this study include its large sample size, well-defined study protocol and the use of direct trainer interviews.
  • One limitation was the inherent vulnerability to survival bias.

Cite This Article

APA
Crawford KL, Finnane A, Greer RM, Barnes TS, Phillips CJC, Woldeyohannes SM, Bishop EL, Perkins NR, Ahern BJ. (2021). Survival Analysis of Training Methodologies and Other Risk Factors for Musculoskeletal Injury in 2-Year-Old Thoroughbred Racehorses in Queensland, Australia. Front Vet Sci, 8, 698298. https://doi.org/10.3389/fvets.2021.698298

Publication

Frontiers in veterinary science
ISSN: 2297-1769
NlmUniqueID: 101666658
Country: Switzerland
Language: English
Volume: 8
Pages: 698298

Researcher Affiliations

Crawford, Kylie L
  • School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia.
  • School of Public Health, The University of Queensland, Herston, QLD, Australia.
Finnane, Anna
  • School of Public Health, The University of Queensland, Herston, QLD, Australia.
Greer, Ristan M
  • Torus Research, Bridgeman Downs, QLD, Australia.
  • Mater Research Institute, The University of Queensland, Brisbane, QLD, Australia.
Barnes, Tamsin S
  • School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia.
  • Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Gatton, QLD, Australia.
Phillips, Clive J C
  • Curtin University Sustainability Policy (CUSP) Institute, Curtin University, Perth, WA, Australia.
Woldeyohannes, Solomon M
  • School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia.
Bishop, Emma L
  • Garrards Equine Veterinary Practice, Albion, QLD, Australia.
Perkins, Nigel R
  • School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia.
Ahern, Benjamin J
  • School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia.

Conflict of Interest Statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Citations

This article has been cited 4 times.
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