More S J
School of Veterinary Science and Animal Production, University of Queensland.
Aust Vet J. 1999 Feb;77(2):105-12. doi: 10.1111/j.1751-0813.1999.tb11678.x.
To develop a profile of the racing careers of Thoroughbred horses in south-eastern Queensland, and to examine factors that affect racing during the first years of racing.
A longitudinal study using the racing records of a defined cohort of Thoroughbred horses that were born on or within 12 months following 1 August 1991. Data collection commenced in 1996 and will continue until all horses cease racing. In this paper two measures of performance were examined: race earnings during the first year of racing and cumulative proportion of horses still racing up to 2 years after their first start. Univariable and multivariable methods were used to describe and identify factors associated with the performance of these horses.
By 31 July 1997, 1804 horses were enrolled in the study including 916, 701, 152 and 35 horses that first raced at 2, 3, 4 and 5 years of age, respectively. During their first year of racing, half the horses earned no more than A$450 from race earnings, and 710 (39.4%) horses earned no money at all. In comparison to poorly performing horses, well-performing horses were more likely to be male, to have started as 2-year-olds and to have had more starts during this year. Of the horses that first started as 2 and 3-year-olds, only 71 and 46% continued racing for at least 1 and 2 years after their first start, respectively. Length of racing life was associated with performance during the first year of racing (number of starts and average earnings per race), and with sex, date of birth and age at first start.
The study confirmed a high wastage among racing Thoroughbreds. As expected, premature retirement from racing was linked to poor performance. During the first year of racing, the race earnings of an estimated 1567 (86.9%) horses were insufficient to cover training costs. The 2-year-old racing cohort outperformed the older racing cohorts in each of the performance measures under investigation. Interpretation of this result, and the long-term effects of 2-year-old racing, was limited by the problem of confounding.
了解昆士兰州东南部纯种马的赛马生涯概况，并研究赛马生涯头几年影响赛马表现的因素。
采用纵向研究，使用1991年8月1日及之后12个月内出生的特定纯种马队列的赛马记录。数据收集始于1996年，并将持续到所有马匹停止比赛。本文研究了两项表现指标：赛马生涯第一年的比赛收入，以及首次参赛后长达2年仍在参赛的马匹累计比例。采用单变量和多变量方法来描述和识别与这些马匹表现相关的因素。
截至1997年7月31日，共有1804匹马纳入研究，其中分别在2岁、3岁、4岁和5岁首次参赛的马匹有916匹、701匹、152匹和35匹。在赛马生涯的第一年，半数马匹的比赛收入不超过450澳元，710匹（39.4%）马匹完全没有收入。与表现不佳的马匹相比，表现良好的马匹更可能为雄性，2岁开始参赛，且当年参赛次数更多。首次在2岁和3岁参赛的马匹中，分别只有71%和46%在首次参赛后至少持续参赛1年和2年。赛马生涯长度与第一年的表现（参赛次数和每场比赛的平均收入）、性别、出生日期和首次参赛年龄有关。
该研究证实纯种赛马的淘汰率很高。不出所料，过早退出比赛与表现不佳有关。在赛马生涯的第一年，估计有1567匹（86.9%）马匹的比赛收入不足以支付训练成本。在各项研究的表现指标中，2岁参赛队列的表现优于年龄较大的参赛队列。由于混杂问题，对这一结果以及2岁参赛的长期影响的解读受到限制。
