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Animals : an open access journal from MDPI2020; 10(11); doi: 10.3390/ani10112046

Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence and Type of Musculoskeletal Injuries Vary between Two-Year-Old and Older Thoroughbred Racehorses.

Abstract: Musculoskeletal injuries (MSI) remain a concerning cause of racehorse morbidity and mortality with important ethical and welfare consequences. Previous research examining risk factors for MSI report inconsistent findings. Age is thought to affect MSI risk, but, to date, there have been no prospective studies comparing MSI in two-year-old versus older horses. This study aimed to: (1) determine the incidence of MSI for two-year-old and older horses, and whether this was affected by training track, season, or rainfall, and (2) determine the types of MSI affecting two-year-old and older horses, and whether horses trialled or raced after injury. A prospective survey was conducted with data collected through personal structured weekly interviews with participating trainers over a 13-month period. Data were analysed using Poisson regression. The incidence of MSI in the current study was low (0.6%). The incidence of MSI in two-year-old horses was higher than older horses (p < 0.001). Types of MSI varied between two-year-old and older horses (p < 0.001) and affected whether horses subsequently trailed or raced from 11 to 23 months after injury (p < 0.001). A larger proportion of two-year-old horses had dorsal metacarpal disease and traumatic lacerations. A smaller proportion of two-year-old horses had suspensory ligament desmitis, superficial digital flexor tendonitis, proximal sesamoid bone fractures, and fetlock joint injuries than older horses. Training track and rainfall did not affect MSI. The season affected MSI in two-year-old horses (p < 0.001) but not older horses. The major limitation was that trainers in this study were metropolitan (city) and our findings may not be generalisable to racehorses in regional (country) areas. Another significant limitation was the assumption that MSI was the reason for failure to trial or race after injury. In conclusion, the incidence of MSI was low in the current study and the types and the risk factors for MSI are different for two-year-old and older horses.
Publication Date: 2020-11-05 PubMed ID: 33167429PubMed Central: PMC7694396DOI: 10.3390/ani10112046Google Scholar: Lookup
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  • Journal Article

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.

The study aims to identify the frequency and kinds of musculoskeletal injuries in both two-year-old and older racehorses under training in Queensland, Australia, and to determine if there are age-related differences in this respect.

Study Overview

  • A survey was designed to understand the nature and frequency of musculoskeletal injuries (MSI) in racehorses of different ages, with a particular focus on two-year-old horses versus their older peers.
  • Participants included trainers who provided data during weekly interviews conducted over a 13-month period.
  • Factors such as the training track, seasonal variations, and rainfall were taken into account to see their impact on injury rates.

Key Findings

  • The overall incidence of MSI was quite low at 0.6%.
  • However, two-year-old horses suffered from MSI more frequently than their older counterparts. The types of MSI also varied according to the age of the racehorse.
  • The health of a horse post-injury, specifically whether they were able to participate in trials or races, was also influenced by the age of the horse and the type of injury sustained.
  • Two-year-olds were found to have a higher frequency of dorsal metacarpal disease and traumatic lacerations; certain injuries such as suspensory ligament desmitis, superficial digital flexor tendonitis, proximal sesamoid bone fractures, and fetlock joint injuries were less common among this age group compared to older horses.
  • The environment, including the training track and rainfall, did not noticeably affect MSI rates.
  • The season seemed to have an impact on the MSI rates in two-year-olds but not in older horses.
  • The study was limited to metropolitan areas, thereby questioning its applicability to racehorses in the countryside.
  • One significant assumption made during the study was that MSI was the sole reason for horses not being able to participate in trials or races post-injury.

Conclusion

  • Even though the overall incidence of MSI was relatively low, the study identified significant age-related differences in both the frequency and types of injuries suffered by racehorses under training.

Cite This Article

APA
Crawford KL, Finnane A, Greer RM, Phillips CJC, Woldeyohannes SM, Perkins NR, Ahern BJ. (2020). Appraising the Welfare of Thoroughbred Racehorses in Training in Queensland, Australia: The Incidence and Type of Musculoskeletal Injuries Vary between Two-Year-Old and Older Thoroughbred Racehorses. Animals (Basel), 10(11). https://doi.org/10.3390/ani10112046

Publication

ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 10
Issue: 11

Researcher Affiliations

Crawford, Kylie L
  • School of Veterinary Science, The University of Queensland, 4343 Gatton, Australia.
  • School of Public Health, The University of Queensland, 4006 Herston, Australia.
Finnane, Anna
  • School of Public Health, The University of Queensland, 4006 Herston, Australia.
Greer, Ristan M
  • Torus Research, 4035 Bridgeman Downs, Australia.
  • School of Medicine, The University of Queensland, 4006 Herston, Australia.
Phillips, Clive J C
  • Curtin University Sustainability Policy (CUSP) Institute, Curtin University, 6845 Perth, Australia.
Woldeyohannes, Solomon M
  • School of Veterinary Science, The University of Queensland, 4343 Gatton, Australia.
Perkins, Nigel R
  • School of Veterinary Science, The University of Queensland, 4343 Gatton, Australia.
Ahern, Benjamin J
  • School of Veterinary Science, The University of Queensland, 4343 Gatton, Australia.

Conflict of Interest Statement

The authors declare no conflict of interest.

References

This article includes 91 references
  1. Jeffcott LB, Rossdale PD, Freestone J, Frank C, Towers-Clark PF. An assessment of wastage in Thoroughbred racing from conception to 4 years of age.. Equine Vet. J. 1982;14:185–198.
  2. Rossdale PD, Hopes R, Digby NJ, Offord K. Epidemiological study of wastage among racehorses 1982 and 1983.. Vet. Rec. 1985;116:66–69.
    doi: 10.1136/vr.116.3.66pubmed: 3976145google scholar: lookup
  3. Clegg PD. Musculoskeletal disease and injury, now and in the future. Part 1: Fractures and fatalities.. Equine Vet. J. 2011;43:643–649.
  4. Bailey C, Reid S, Hodgson D, Suann C, Rose R. Risk factors associated with musculoskeletal injuries in Australian Thoroughbred racehorses.. Prev. Vet. Med. 1997;32:47–55.
    doi: 10.1016/s0167-5877(97)00009-3pubmed: 9361320google scholar: lookup
  5. Estberg L, Stover SM, Gardner IA, Johnson BJ, Case JT, Ardans A, Read DH, Anderson ML, Barr BC, Daft BM. Fatal musculoskeletal injuries incurred during racing and training in thoroughbreds.. J. Am. Vet. Med. Assoc. 1996;208:92–96.
    pubmed: 8682713
  6. Parkin T, Rossdale PD. Epidemiology of equine performance wastage: Importance of analysing facts and implementing their message in management.. Equine Vet. J. 2006;38:98–100.
    doi: 10.2746/042516406776563279pubmed: 16536374google scholar: lookup
  7. Cohen ND, Peloso JG, Mundy GD, Fisher ME, Holland R, Little TV, Misheff MM, Watkins JP, Honnas CM, Moyer W. Racing-related factors and results of prerace physical inspection and their association with musculoskeletal injuries incurred in thoroughbreds during races.. J. Am. Vet. Med. Assoc. 1997;211:454–463.
    pubmed: 9267508
  8. Hitchens PL, Hill AE, Stover SM. The role of catastrophic injury or sudden death of the horse in race-day jockey falls and injuries in California, 2007–2012.. Equine Vet. J. 2016;48:50–56.
    doi: 10.1111/evj.12392pubmed: 25417895google scholar: lookup
  9. Diab SS, Poppenga R, Uzal FA. Sudden death in racehorses: Postmortem examination protocol.. J. Vet. Diagn. Investig. 2017;29:442–449.
    doi: 10.1177/1040638716687004pubmed: 28114865google scholar: lookup
  10. Johnson BJ, Stover SM, Daft BM, Kinde H, Read DH, Barr BC, Anderson M, Moore J, Woods L, Stoltz J. Causes of death in racehorses over a 2 year period.. Equine Vet. J. 1994;26:327–330.
  11. Perkins NR, Reid S, Morris R. Profiling the New Zealand Thoroughbred racing industry. 2. Conditions interfering with training and racing.. N. Z. Vet. J. 2005;53:69–76.
    doi: 10.1080/00480169.2005.36471pubmed: 15731837google scholar: lookup
  12. Boden L, Anderson GA, Charles JA, Morgan KL, Morton JM, Parkin T, Slocombe RF, Clarke AF. Risk of fatality and causes of death of Thoroughbred horses associated with racing in Victoria, Australia: 1989–2004.. Equine Vet. J. 2006;38:312–318.
    doi: 10.2746/042516406777749182pubmed: 16866197google scholar: lookup
  13. Rosanowski SM, Chang YM, Stirk AJ, Verheyen KLP. Descriptive epidemiology of veterinary events in flat racing Thoroughbreds in Great Britain (2000 to 2013). Equine Vet. J. 2016;49:275–281.
    doi: 10.1111/evj.12592pubmed: 27208544google scholar: lookup
  14. DeLay J. Postmortem findings in Ontario racehorses, 2003–2015.. J. Vet. Diagn. Investig. 2017;29:457–464.
    doi: 10.1177/1040638717700690pubmed: 28382856google scholar: lookup
  15. Physick-Sheard PW, Avison A, Chappell E, MacIver M. Ontario racehorse death registry, 2003–2015: Descriptive analysis and rates of mortality.. Equine Vet. J. 2017;51:64–76.
    doi: 10.1111/evj.12955pubmed: 29672910google scholar: lookup
  16. Parkin TDH, Clegg PD, French NP, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Race-and course-level risk factors for fatal distal limb fracture in racing Thoroughbreds.. Equine Vet. J. 2010;36:521–526.
    doi: 10.2746/0425164044877332pubmed: 15460077google scholar: lookup
  17. Parkin T, Clegg PD, French N, Proudman CJ, Riggs CM, Singer ER, Webbon PM, Morgan KL. Horse-level risk factors for fatal distal limb fracture in racing Thoroughbreds in the UK.. Equine Vet. J. 2004;36:513–519.
    doi: 10.2746/0425164044877387pubmed: 15460076google scholar: lookup
  18. Wood JLN, Harkins L, Rogers K, editors. A retrospective study of factors associated with racehorse fatality on British racecourses from 1990–1999; Proceedings of the 13th International Conference of Racing Analysts and Veterinarians; Cambridge, UK.. 1–8 August 2000; Newmarket, UK: R & W Publications; 2001.
  19. Bailey CJ, Reid SW, Hodgson DR, Bourke JM, Rose RJ. Flat, hurdle and steeple racing: Risk factors for musculoskeletal injury.. Equine Vet. J. 1998;30:498–503.
  20. Peloso JG, Mundy GD, Cohen ND. Prevalence of, and factors associated with musculoskeletal racing injuries of thoroughbreds.. J. Am. Vet. Med. Assoc. 1994;204:620–626.
    pubmed: 8163419
  21. Verheyen KLR, Wood JLN. Descriptive epidemiology of fractures occurring in British Thoroughbred racehorses in training.. Equine Vet. J. 2004;36:167–173.
    doi: 10.2746/0425164044868684pubmed: 15038441google scholar: lookup
  22. Ely ER, Avella CS, Price JS, Smith RKW, Wood JLN, Verheyen KLP. Descriptive epidemiology of fracture, tendon and suspensory ligament injuries in National Hunt racehorses in training.. Equine Vet. J. 2009;41:372–378.
    doi: 10.2746/042516409X371224pubmed: 19562899google scholar: lookup
  23. Allen SE, Rosanowski SM, Stirk AJ, Verheyen KLP. Description of veterinary events and risk factors for fatality in National Hunt flat racing Thoroughbreds in Great Britain (2000–2013). Equine Vet. J. 2017;49:700–705.
    doi: 10.1111/evj.12676pubmed: 28235142google scholar: lookup
  24. Estberg L, Gardner IA, Stover SM, Johnson BJ, Case JT, Ardans A. Cumulative racing-speed exercise distance cluster as a risk factor for fatal musculoskeletal injury in Thoroughbred racehorses in California.. Prev. Vet. Med. 1995;24:253–263.
  25. Estberg L, Gardner IA, Stover SM, Johnson BJ. A case-crossover study of intensive racing and training schedules and risk of catastrophic musculoskeletal injury and lay-up in California Thoroughbred racehorses.. Prev. Vet. Med. 1998;33:159–170.
    doi: 10.1016/S0167-5877(97)00047-0pubmed: 9500171google scholar: lookup
  26. Verheyen KLP, Newton J, Price J, Wood J. A case-control study of factors associated with pelvic and tibial stress fractures in Thoroughbred racehorses in training in the UK.. Prev. Vet. Med. 2006;74:21–35.
  27. Riggs CM, Whitehouse GH, Boyde A. Pathology of the distal condyles of the third metacarpal and third metatarsal bones of the horse.. Equine Vet. J. 1999;31:140–148.
  28. Riggs CM, Whitehouse GH, Boyde A. Structural variation of the distal condyles of the third metacarpal and third metatarsal bones in the horse.. Equine Vet. J. 1999;31:130–139.
  29. Riggs C. Fractures–A preventable hazard of racing Thoroughbreds?. Vet. J. 2002;163:19–29.
    doi: 10.1053/tvjl.2001.0610pubmed: 11749133google scholar: lookup
  30. Radtke CL, Danova NA, Scollay MC, Santschi EM, Markel MD, Gómez TDC, Muir P. Macroscopic changes in the distal ends of the third metacarpal and metatarsal bones of Thoroughbred racehorses with condylar fractures.. Am. J. Vet. Res. 2003;64:1110–1116.
    doi: 10.2460/ajvr.2003.64.1110pubmed: 13677388google scholar: lookup
  31. Stepnik MW, Radtke CL, Scollay MC, Oshel PE, Albrecht RM, Santschi EM, Markel MD, Muir P. Scanning electron microscopic examination of third metacarpal/third metatarsal bone failure surfaces in thoroughbred racehorses with condylar fracture.. Vet. Surg. 2004;33:2–10.
  32. Parkin T, Clegg PD, French N, Proudman C, Riggs CM, Singer E, Webbon P, Morgan K. Catastrophic fracture of the lateral condyle of the third metacarpus/metatarsus in UK racehorses–Fracture descriptions and pre-existing pathology.. Vet. J. 2006;171:157–165.
    doi: 10.1016/j.tvjl.2004.10.009pubmed: 16427592google scholar: lookup
  33. Mason TA, Bourke JM. Closure of the distal radial epiphysis and its relationship to unsoundness in two-year old Thoroughbreds.. Aust. Vet. J. 1973;49:221–228.
  34. Sun TC, Riggs CM, Cogger N, Wright J, Alawneh J. Noncatastrophic and catastrophic fractures in racing Thoroughbreds at the Hong Kong Jockey Club.. Equine Vet. J. 2018;51:77–82.
    doi: 10.1111/evj.12953pubmed: 29672909google scholar: lookup
  35. Thrusfield M, Christley R, Brown H, Diggle PJ, French N, Howe K, Kelly L, O’Connor A, Sargeant J, Wood H. Veterinary Epidemiology.. 4th ed. Wiley; Hoboken, NJ, USA: 2018.
  36. Grimes DA, Schulz KF. Cohort studies: Marching towards outcomes.. Lancet. 2002;359:341–345.
    doi: 10.1016/S0140-6736(02)07500-1pubmed: 11830217google scholar: lookup
  37. Dohoo I, Martin SW, Stryhn H. Veterinary Epidemiologic Research.. 3rd ed. VER, Inc.; Charlotte, NC, Canada: 2014.
  38. Grimes DA, Schulz KF. Bias and causal associations in observational research.. Lancet. 2002;359:248–252.
    doi: 10.1016/S0140-6736(02)07451-2pubmed: 11812579google scholar: lookup
  39. Reed SR, Jackson BF, Mc Ilwraith CW, Wright IM, Pilsworth R, Knapp S, Wood JLN, Price JS, Verheyen KLP. Descriptive epidemiology of joint injuries in Thoroughbred racehorses in training.. Equine Vet. J. 2011;44:13–19.
  40. Cogger N, Evans DL, Hodgson DR, Reid SW, Perkins N. Incidence rate of musculoskeletal injuries and determinants of time to recovery in young Australian Thoroughbred racehorses.. Aust. Vet. J. 2008;86:473–480.
  41. Perkins NR, Reid S, Morris R. Profiling the New Zealand Thoroughbred racing industry. 1. Training, racing and general health patterns.. N. Z. Vet. J. 2005;53:59–68.
    doi: 10.1080/00480169.2005.36470pubmed: 15731836google scholar: lookup
  42. Hitchens P, Hill AE, Stover SM. Relationship between historical lameness, medication usage, surgery, and exercise with catastrophic musculoskeletal injury in racehorses.. Front. Vet. Sci. 2018;5.
    doi: 10.3389/fvets.2018.00217pmc: PMC6137211pubmed: 30246014google scholar: lookup
  43. Hitchens P, Morrice-West A, Stevenson M, Whitton R. Meta-analysis of risk factors for racehorse catastrophic musculoskeletal injury in flat racing.. Vet. J. 2019;245:29–40.
    doi: 10.1016/j.tvjl.2018.11.014pubmed: 30819423google scholar: lookup
  44. Hill AE, Gardner IA, Carpenter TE, Stover SM. Effects of injury to the suspensory apparatus, exercise, and horseshoe characteristics on the risk of lateral condylar fracture and suspensory apparatus failure in forelimbs of thoroughbred racehorses.. Am. J. Vet. Res. 2004;65:1508–1517.
    doi: 10.2460/ajvr.2004.65.1508pubmed: 15566089google scholar: lookup
  45. Vallance SA, Case JT, Entwistle RC, Kinde H, Barr BC, Moore J, Anderson ML, Arthur RM, Stover SM. Characteristics of Thoroughbred and Quarter Horse racehorses that sustained a complete scapular fracture.. Equine Vet. J. 2011;44:425–431.
  46. Vallance SA, Entwistle RC, Hitchens P, Gardner IA, Stover SM. Case-control study of high-speed exercise history of Thoroughbred and Quarter Horse racehorses that died related to a complete scapular fracture.. Equine Vet. J. 2012;45:284–292.
  47. Verheyen KLP, Henley WE, Price JS, Wood JLN. Training-related factors associated with dorsometacarpal disease in young Thoroughbred racehorses in the UK.. Equine Vet. J. 2010;37:442–448.
    doi: 10.2746/042516405774480085pubmed: 16163947google scholar: lookup
  48. Pinchbeck GL, Clegg PD, Proudman CJ, Morgan KL, French N. A prospective cohort study to investigate risk factors for horse falls in UK hurdle and steeplechase racing.. Equine Vet. J. 2004;36:595–601.
    doi: 10.2746/0425164044864552pubmed: 15581324google scholar: lookup
  49. Beisser AL, McClure S, Wang C, Soring K, Garrison R, Peckham B. Evaluation of catastrophic musculoskeletal injuries in Thoroughbreds and Quarter Horses at three Midwestern racetracks.. J. Am. Vet. Med. Assoc. 2011;239:1236–1241.
    doi: 10.2460/javma.239.9.1236pubmed: 21999798google scholar: lookup
  50. . Horse Racing Statistics.. [(accessed on 12 December 2017)];2017 Available online: https://punters.com.au.
  51. . Meteorology Climate Data Online 2018.. [(accessed on 2 February 2019)]; Available online: http://www.bom.gov.au/climate/data/.
  52. Grimes DA, Schulz KF. Descriptive studies: What they can and cannot do.. Lancet. 2002;359:145–149.
    doi: 10.1016/S0140-6736(02)07373-7pubmed: 11809274google scholar: lookup
  53. Cogger N, Perkins N, Hodgson D, Reid S, Evans D. Risk factors for musculoskeletal injuries in 2-year-old Thoroughbred racehorses.. Prev. Vet. Med. 2006;74:36–43.
  54. Ramzan PHL, Palmer L. Musculoskeletal injuries in Thoroughbred racehorses: A study of three large training yards in Newmarket, UK (2005–2007). Vet. J. 2011;187:325–329.
    doi: 10.1016/j.tvjl.2009.12.019pubmed: 20089426google scholar: lookup
  55. Boston RC, Nunamaker DM. Gait and speed as exercise components of risk factors associated with onset of fatigue injury of the third metacarpal bone in 2-year-old Thoroughbred racehorses: The Laboratory Small Ruminant.. Am. J. Vet. Res. 2000;61:602–608.
    doi: 10.2460/ajvr.2000.61.602pubmed: 10850832google scholar: lookup
  56. Nunamaker DM, Butterweck DM, Provost MT. Fatigue fractures in thoroughbred racehorses: Relationships with age, peak bone strain, and training.. J. Orthop. Res. 1990;8:604–611.
    doi: 10.1002/jor.1100080417pubmed: 2355300google scholar: lookup
  57. Crevier-Denoix N, Collobert C, Pourcelot P, Denoix J, Sanaa M, Geiger D, Bernard N, Ribot X, Bortolussi C, Bousseau B. Mechanical properties of pathological equine superficial digital flexor tendons.. Equine Vet. J. 1997;29:23–26.
  58. Jones BH, Thacker SB, Gilchrist J, Kimsey CD, Sosin DM. Prevention of lower extremity stress fractures in athletes and soldiers: A systematic review.. Epidemiol. Rev. 2002;24:228–247.
    doi: 10.1093/epirev/mxf011pubmed: 12762095google scholar: lookup
  59. Eckard TG, Padua DA, Hearn DW, Pexa BS, Frank BS. The relationship between training load and injury in athletes: A systematic review.. Sports Med. 2018;48:1929–1961.
    doi: 10.1007/s40279-018-0951-zpubmed: 29943231google scholar: lookup
  60. Dyson PK, Jackson BF, Pfeiffer DU, Price JS. Days lost from training by two-and three-year-old Thoroughbred horses: A survey of seven UK training yards.. Equine Vet. J. 2008;40:650–657.
    doi: 10.2746/042516408X363242pubmed: 19165934google scholar: lookup
  61. Bourke JM, editor. Wastage in Thoroughbreds.. Annual Seminar of the Equine Branch. New Zealand Veterinary Association; Wellington, New Zealand: 1995.
  62. Velie BD, Knight P, Wade CM, Hamilton NA, Thomson PC. The association of age at first start with career length in the Australian Thoroughbred racehorse population.. Equine Vet. J. 2012;45:410–413.
  63. Bailey C, Rose R, Reid S, Hodgson. Factors associated with time until first race and career duration for Thoroughbred racehorses.. Am. J. Vet. Res. 1999;60:1196–1200.
    pubmed: 10791929
  64. Tanner JC, Rogers CW, Firth EC. The association of 2-year-old training milestones with career length and racing success in a sample of Thoroughbred horses in New Zealand.. Equine Vet. J. 2012;45:20–24.
  65. Sobczynska M. The effect of selected factors on length of racing career in Thoroughbred racehorses in Poland.. Anim. Sci. Pap. Rep. 2007;25:131–141.
  66. Bailey C, Rose R, Reid S, Hodgson. Wastage in the Australian Thoroughbred racing industry: A survey of Sydney trainers.. Aust. Vet. J. 1997;75:64–66.
  67. Smith RK, Birch H, Patterson-Kane J, Firth EC, Williams L, Cherdchutham W, Van Weeren WR, Goodship AE. Should equine athletes commence training during skeletal development?: Changes in tendon matrix associated with development, ageing, function and exercise.. Equine Vet. J. 2010;31:201–209.
  68. Patterson-Kane JC, Parry DAD, Birch HL, Goodship AE, Firth EC. An age-related study of morphology and cross-link composition of collagen fibrils in the digital flexor tendons of young thoroughbred horses.. Connect. Tissue Res. 1997;36:253–260.
    doi: 10.3109/03008209709160225pubmed: 9512893google scholar: lookup
  69. Patterson-Kane J, Wilson AM, Firth EC, Parry DAD, Goodship AE. Comparison of collagen fibril populations in the superficial digital flexor tendons of exercised and nonexercised Thoroughbreds.. Equine Vet. J. 1997;29:121–125.
  70. Patterson-Kane J, Wilson AM, Firth EC, Parry DAD, Goodship AE. Exercise-related alterations in crimp morphology in the central regions of superficial digital flexor tendons from young thoroughbreds: A controlled study.. Equine Vet. J. 1998;30:61–64.
  71. Kasashima Y, Takahashi T, Smith RKW, Goodship AE, Kuwano A, Ueno T, Hirano S. Prevalence of superficial digital flexor tendonitis and suspensory desmitis in Japanese Thoroughbred flat racehorses in 1999.. Equine Vet. J. 2010;36:346–350.
    doi: 10.2746/0425164044890580pubmed: 15163043google scholar: lookup
  72. Patterson-Kane JC, Firth EC, Parry DA, Wilson AM, E Goodship A. Effects of training on collagen fibril populations in the suspensory ligament and deep digital flexor tendon of young thoroughbreds.. Am. J. Vet. Res. 1998;59:64–68.
    pubmed: 9442247
  73. Whitton RC, Trope GD, Ghasem-Zadeh A, Anderson GA, Parkin TD, Mackie EJ, Seeman E. Third metacarpal condylar fatigue fractures in equine athletes occur within previously modelled subchondral bone.. Bone. 2010;47:826–831.
    doi: 10.1016/j.bone.2010.07.019pubmed: 20659599google scholar: lookup
  74. Stover SM, Johnson BJ, Daft BM, Read DH, Anderson M, Barr BC, Kinde H, Moore J, Stoltz J, Ardans AA. An association between complete and incomplete stress fractures of the humerus in racehorses.. Equine Vet. J. 1992;24:260–263.
  75. Anthenill LA, Gardner IA, Pool RR, Garcia T, Stover SM. Comparison of macrostructural and microstructural bone features in Thoroughbred racehorses with and without midbody fracture of the proximal sesamoid bone.. Am. J. Vet. Res. 2010;71:755–765.
    doi: 10.2460/ajvr.71.7.755pubmed: 20594077google scholar: lookup
  76. Mohammed HO, Hill T, Lowe J. Risk factors associated with injuries in Thoroughbred horses.. Equine Vet. J. 1991;23:445–448.
  77. Williams RB, Harkins LS, Hammond CJ, Wood JLN. Racehorse injuries, clinical problems and fatalities recorded on British racecourses from flat racing and National Hunt racing during 1996, 1997 and 1998.. Equine Vet. J. 2010;33:478–486.
    doi: 10.2746/042516401776254808pubmed: 11558743google scholar: lookup
  78. Cheney J, Shen CK, Wheat JD. Relationship of racetrack surface to lameness in the thoroughbred racehorse.. Am. J. Vet. Res. 1973;34:1285–1289.
    pubmed: 4147847
  79. Symons JE, Hawkins DA, Fyhrie DP, Upadhyaya SK, Stover SM. Hitting the ground running: Evaluating an integrated racehorse limb and race surface computational model.. J. Biomech. 2016;49:1711–1717.
  80. Symons JE, Hawkins DA, Fyhrie DP, Upadhyaya SK, Stover SM. Modelling the effect of race surface and racehorse limb parameters on in silico fetlock motion and propensity for injury.. Equine Vet. J. 2017;49:681–687.
    doi: 10.1111/evj.12672pubmed: 28128865google scholar: lookup
  81. Setterbo JJ, Fyhrie PB, Hubbard M, Upadhyaya SK, Stover SM. Dynamic properties of a dirt and a synthetic equine racetrack surface measured by a track-testing device.. Equine Vet. J. 2012;45:25–30.
  82. Kai M, Takahashi T, Aoki O, Oki H. Influence of rough track surfaces on components of vertical forces in cantering Thoroughbred horses.. Equine Vet. J. 2010;31:214–217.
  83. Maeda Y, Hanada M, Oikawa M-A. Epidemiology of racing injuries in Thoroughbred racehorses with special reference to bone fractures: Japanese experience from the 1980s to 2000s.. J. Equine Sci. 2016;27:81–97.
    doi: 10.1294/jes.27.81pmc: PMC5048355pubmed: 27703403google scholar: lookup
  84. Boyde A, Firth EC. Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 8. Quantitative back-scattered electron scanning electron microscopy and confocal fluorescence microscopy of the epiphysis of the third metacarpal bone.. N. Z. Vet. J. 2005;53:123–132.
    doi: 10.1080/00480169.2005.36489pubmed: 15846396google scholar: lookup
  85. Perkins N, Reid S, Morris R. Risk factors for musculoskeletal injuries of the lower limbs in Thoroughbred racehorses in New Zealand.. N. Z. Vet. J. 2005;53:171–183.
    doi: 10.1080/00480169.2005.36502pubmed: 16012587google scholar: lookup
  86. Tanner J, Rogers C, Bolwell C, Cogger N, Gee E, Mcllwraith W. Analysis of failure to finish a race in a cohort of thoroughbred racehorses in New Zealand.. Animals. 2016;6:36.
    doi: 10.3390/ani6060036pmc: PMC4929416pubmed: 27231944google scholar: lookup
  87. Boden LA, Anderson GA, Charles JA, Morgan KL, Morton JM, Parkin TD, Clarke AF, Slocombe RF. Risk factors for Thoroughbred racehorse fatality in flat starts in Victoria, Australia (1989–2004). Equine Vet. J. 2007;39:430–437.
    doi: 10.2746/042516407X183162pubmed: 17910268google scholar: lookup
  88. Delgado-Rodríguez M, Llorca J. Bias.. J. Epidemiol. Community Health. 2004;58:635.
    doi: 10.1136/jech.2003.008466pmc: PMC1732856pubmed: 15252064google scholar: lookup
  89. Verheyen K, Price J, Lanyon L, Wood J. Exercise distance and speed affect the risk of fracture in racehorses.. Bone. 2006;39:1322–1330.
    doi: 10.1016/j.bone.2006.05.025pubmed: 16926125google scholar: lookup
  90. Ho PM, Peterson PN, Masoudi FA. Evaluating the Evidence. Is there a rigid hierarchy?. Circulation. 2008;118:1675–1684.
  91. . Racing Australia Database 2017–2020.. [(accessed on 1 September 2020)]; Available online: http://www.racingaustralia.horse/home.aspx.