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Thoroughbred foals given extensive turnout in larger pastures during their first six months of life, and those weaned at an older age, are more likely to enter training, race more frequently, and earn greater prize money later in life.
The study provides new insight into how gestational and early-life management can influence the growth, development, and long-term athletic performance of racehorses. It aimed to enhance understanding of how early-life health and husbandry practices affect both racing outcomes and the financial sustainability of Thoroughbred breeding enterprises.
According to the research team, this is the first UK-based field study to comprehensively evaluate the effects of early-life exposures, particularly exercise and turnout, on later-life milestones and race performance in Thoroughbreds. The findings offer direct practical applications for stud farms, supporting both horse welfare and industry retention, in line with the Horse Welfare Board’s strategy for improving the welfare of racehorses.
The research, led by Dr Rebecca Mouncey, Post-Doctoral Research Fellow at the RVC, was conducted as a prospective cohort study. The team followed 129 flat-race bred Thoroughbred foals, born in 2019 and 2020 on six stud farms across the UK, from birth through to training and early racing careers.
Detailed data were collected on each dam’s reproductive history and health during pregnancy, alongside daily records of foal management, health status, turnout duration and area, and any veterinary-attended illnesses or injuries. These records were maintained until the foals left their stud farms or exited the study. Racing performance data were subsequently collated from industry databases up to the horses’ fourth year of life.
Statistical analyses, including mixed-effects logistic and linear regression models (with farm, mare, and stallion as random effects), were used to examine associations between gestational and early-life exposures and later racing performance.
Of the 129 horses studied, 76% (98/129) went on to race by the age of four, with a median of seven starts (interquartile range [IQR] 4–11) and median prize earnings of £6,898 (IQR £1,712–£17,987).
Significant associations were identified between early-life management factors and later performance:
- Turnout: Foals that spent more time turned out at pasture during their first six months of life were more likely to race and earned more prize money.
- Increasing average daily turnout time and pasture size were associated with higher odds of racing (Odds Ratio 1.31, 95% CI: 1.09–1.58, p = 0.004) and increased total prize earnings (β = 0.32 lnGBP, 95% CI: 0.03–0.61, p = 0.03).
- Weaning Age: Foals weaned later were more likely to race and made a greater number of race starts.
- Each additional day of age at weaning increased both the odds of racing (OR 1.03, 95% CI: 1.01–1.05, p < 0.05) and total number of runs (β = 0.09, 95% CI: 0.04–0.14, p < 0.05).
These results indicate that management during the first six months of life plays a critical role in preparing Thoroughbreds for future athletic success.
The findings demonstrate that early-life turnout and weaning practices significantly affect race participation, performance, and financial outcomes. Providing foals with ample turnout opportunities and delaying weaning until after this key developmental window may support positive musculoskeletal adaptation and improved future performance.
Dr Mouncey noted that: “This study is the first of its kind to evaluate the impact of early-life experiences on later racing performance in Thoroughbreds. Our findings highlight that the first six months of life represent a crucial developmental period in which management practices must promote optimal tissue development and welfare.”
The study was funded by the Horserace Betting Levy Board, the Racing Foundation, and the RVC’s Mellon Fund for Equine Research, and is published in the Equine Veterinary Journal.
For more details, see:
Mouncey R, de Mestre AM, Arango-Sabogal JC, Verheyen KL.
Born to run? Associations between gestational and early-life exposures and later-life performance outcomes in Thoroughbreds.
Equine Vet J. (2025).
