Factors associated with failure of thoroughbred horses to train and race.

REASONS FOR PERFORMING STUDY: The low productivity associated with training and racing of young Thoroughbreds (TBs) in the UK due to athletic inability, injury and disease requires further study.

OBJECTIVES: To identify the time points and causes of losses during growth and training phases of a cohort of 1022 TB foals born in 1999 up to the end of their third year.

METHODS: Movement and fate of 1022 Thoroughbred foals conceived in 1998 and born live in 1999 were monitored from birth to age 3 years. Those (n = 562) that entered training age 2 and/or 3 years with one of 161 registered trainers in Britain or Ireland in 2001/2 were analysed as to their subsequent performance and the incidence of 9 common injuries or infective or metabolic illnesses.

RESULTS: Of the 1022 foals identified, 537 (52%) entered training at age 2 years, 289 (28%) were exported, 60 (6%) were kept as 'stores' for National Hunt (NH) racing, 58 (6%) died or were destroyed, 25 (2%) were waiting to enter training at age 3 years, 17 (2%) were never intended for racing and 36 (4%) were untraceable. Race records showed that 327 (61%) of the 2-year-olds in training competed one or more times, 95 (18%) won and 165 (31%) were placed. Only 28 (5%) earned enough prize money to cover their training fees. Sore shins and inflammatory airway disease (IAD) were the 2 ailments most commonly encountered. In 2002, 431 (80%) of the previous year's 2-year-olds remained in training aged 3 years and 25 entered training having not raced previously. Of the 456 3-year-olds in training, 347 (76%) raced one or more times 138 (30%) won, 218 (48%) were placed and 78 (17%) recouped their training fees. Joint problems and sore shins were the ailments most commonly suffered and, with the exception of rhabdomyolysis ('tying up'), colts and geldings suffered a higher rate of muscloskeletal injuries than fillies.

CONCLUSION: Previous reports of high nonrun and nonplaced rates, high incidence of injury and cost-ineffectiveness of 2-year-olds in flat-race training were confirmed.

POTENTIAL RELEVANCE: This study lays the basis for further studies of the facets involved in wastage.