The association of age at first start with career length in the Australian Thoroughbred racehorse population.
Abstract: Studies of Thoroughbred racing populations have provided evidence of a positive effect on racing careers for horses that commence racing as 2-year-olds. Currently, research investigating the presence of this effect in the Australian Thoroughbred racing population is limited. Objective: To investigate the association between age at first start and career length in the Australian Thoroughbred population and estimate the risk of racing retirement for horses racing in Australia based on age at first start, career earnings, number of starts as a 2-year-old and distance raced. Methods: Data were collected for Thoroughbreds, born on or after 1 January 1998, that had raced between 1 August 2000 and 22 February 2011 in Australia. A Kaplan-Meier survival curve, stratified by age group, was produced for career length. A Cox proportional hazard model was fitted to assess factors influencing the risk of retirement from racing. The model included sex, age at first start, career earnings, number of starts as a 2-year-old, distance raced and appropriate interaction terms. Results: The study population included 117,088 horses. Geldings had significantly (P<0.001) longer careers than females and intact males, and females had significantly (P<0.001) longer careers than intact males. Risk of retirement from racing decreased with a younger age at first start, a higher number of starts as a 2-year-old, and a longer average distance raced. For intact males, the risk of retirement from racing increased as earnings increased, while for females and geldings the risk of retirement from racing decreased as earnings increased. Conclusions: The introduction of young Thoroughbreds to racing appears to have no apparent adverse effects on these horses racing in Australia. The impact of some risk factors associated with retirement from racing varied between sexes and should be considered when evaluating career outcomes.
© 2012 EVJ Ltd.
Publication Date: 2012-09-26 PubMed ID: 23009388DOI: 10.1111/j.2042-3306.2012.00651.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study explores the association of the age at which a Thoroughbred horse first starts racing with the length of its racing career in Australia. It concludes that early introduction to racing doesn’t seem to negatively impact the horse’s career in the country and various factors related to the horse’s retirement from racing are also sex-dependent.
Research Methodology
- The data used for this study were collected for Thoroughbred horses, born on or after January 1, 1998, that raced between August 1, 2000, and February 22, 2011, in Australia.
- A Kaplan-Meier survival curve, segregated by the age group, was created for understanding the career length of horses.
- A Cox proportional hazard model was applied to assess factors influencing the risk of retirement from racing. The model considered several parameters, such as sex, age at the first race, career earnings, number of starts as a 2-year-old, and the average distance raced.
Key Findings
- The population for the study consisted of 117,088 horses. It was found that geldings (castrated male horses) had significantly longer careers than females and intact males.
- The data suggested a stark association between various factors and the risk of retirement from horse racing. A younger age at the first start, a higher frequency of starts at the age of 2 and a longer average distance raced leads to a lower risk of retirement from racing.
- On the contrary, the earnings observed a different trend in terms of the risk of retirement from racing. For intact males, the risk of retirement increased as earnings increased. However, for females and geldings, the risk of retirement from racing decreased with more earnings.
Conclusions
- The results suggest that starting racing early does not exhibit any apparent adverse effects on Thoroughbred horses in Australia.
- The study also suggests the evaluation of career outcomes should be done with consideration of certain risk factors, such as sex, which showed a varied impact in terms of retirement from racing.
Cite This Article
APA
Velie BD, Knight PK, Thomson PC, Wade CM, Hamilton NA.
(2012).
The association of age at first start with career length in the Australian Thoroughbred racehorse population.
Equine Vet J, 45(4), 410-413.
https://doi.org/10.1111/j.2042-3306.2012.00651.x Publication
Researcher Affiliations
- Faculty of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia. brandon.velie@sydney.edu.au
MeSH Terms
- Animals
- Australia
- Female
- Horses / physiology
- Male
- Physical Conditioning, Animal
- Proportional Hazards Models
- Running
- Sports
Citations
This article has been cited 12 times.- Siegers E, van den Broek J, Sloet van Oldruitenborgh-Oosterbaan M, Munsters C. Longitudinal Training and Workload Assessment in Young Friesian Stallions in Relation to Fitness, Part 2-An Adapted Training Program.. Animals (Basel) 2023 Feb 14;13(4).
- Stallones L, McManus P, McGreevy P. Sustainability and the Thoroughbred Breeding and Racing Industries: An Enhanced One Welfare Perspective.. Animals (Basel) 2023 Jan 31;13(3).
- Crawford KL, Ahern BJ. Investigations into Thoroughbred racehorse welfare in Queensland Australia focused on musculoskeletal injuries and retirement.. Anim Front 2022 Jun;12(3):59-62.
- Rogers CW, Gee EK, Dittmer KE. Growth and Bone Development in the Horse: When Is a Horse Skeletally Mature?. Animals (Basel) 2021 Nov 29;11(12).
- 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.
- Shrestha K, Gilkerson JR, Stevenson MA, Flash ML. Drivers of exit and outcomes for Thoroughbred racehorses participating in the 2017-2018 Australian racing season.. PLoS One 2021;16(9):e0257581.
- Logan AA, Nielsen BD. Training Young Horses: The Science behind the Benefits.. Animals (Basel) 2021 Feb 9;11(2).
- 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 and Type of Musculoskeletal Injuries Vary between Two-Year-Old and Older Thoroughbred Racehorses.. Animals (Basel) 2020 Nov 5;10(11).
- Flash ML, Wong ASM, Stevenson MA, Gilkerson JR. Barriers to entering race training before 4 years of age for Thoroughbred horses born in the 2014 Australian foal crop.. PLoS One 2020;15(8):e0237003.
- Palmer AL, Bolwell CF, Stafford KJ, Gal A, Rogers CW. Patterns of Racing and Career Duration of Racing Greyhounds in New Zealand.. Animals (Basel) 2020 May 5;10(5).
- Parkes RSV, Weller R, Pfau T, Witte TH. The Effect of Training on Stride Duration in a Cohort of Two-Year-Old and Three-Year-Old Thoroughbred Racehorses.. Animals (Basel) 2019 Jul 22;9(7).
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