Musculoskeletal injuries were responsible for 14.2 per cent of training interruptions in a group of two-year-old thoroughbreds assessed as part of a New Zealand study.
Females had a lesser risk of interruptions due to musculoskeletal injury before the first trial compared with males, the researchers reported in the New Zealand Veterinary Journal.
The study did not find any association between interruptions due to musculoskeletal injury and the number of high-speed exercise sessions during training.
The Massey University researchers set out to assess the risk factors that led to interruptions in training before the first trial start of two-year-old thoroughbreds.
The study team, led by Dr Charlotte Bolwell, obtained data from 14 trainers in the North Island’s Central and Northern Districts on 205 horses that undertook, in total, 11,051 training days.
The information was collected over the 2008-09 and 2009-10 racing seasons.
The majority of training interruptions – 85.8 per cent – were voluntary, when the trainer felt the horse would benefit from a break, sometimes as part of their standard training regime, or that the horse needed time to “mature” or “strengthen and grow”.
The average time to a voluntary interruption before the first trial was 58 days after starting training.
“>Of the horses given a voluntary spell, 50 per cent were given as part of the trainer’s methods or practices; 32.7 per cent were for the horse to grow or strengthen; 12.3 per cent were because the animal was considered immature; 1.8 per cent were for a rest; 1.8 per cent were for gelding; and 1.2 per cent of the youngsters were assessed as mentally not ready.
There were 30 horses given involuntary breaks, representing 15.6 per cent of the horses that had an interruption to training during the study.
Of these, 25 animals, or 83 per cent, suffered musculoskeletal injuries, resulting in a median break of 67 days. Three animals, or 10 per cent, suffered accidental injuries, resulting in an average 32 days off.
Bolwell said risk factors for musculoskeletal injury during training and racing had been identified in earlier research by others, but there was little information about reasons for retirement or failing to train and race due to non-health events.
A 2004 study found that most retirements from training and racing were voluntary, based on a trainer’s decision, and were most likely due to poor performance or lack of talent.
“Retirements and lost training days are of concern as they have economic implications for the trainer and the wider racing industry, and often lead to significant associated costs and effects,” the Massey researchers wrote.
Out of 205 horses, 29.8 per cent reached their first trial without an interruption to training.
“Gender was found to be associated with the risk of interruption due to musculoskeletal injury,” the researchers wrote.
“In agreement with the literature … females were less likely than males to experience an interruption due to musculoskeletal injury.
“Despite this, gender represents a factor that cannot be easily modified by a racing industry. However, a recent study by Bolwell and her colleagues showed that the average exercise accumulated by yearlings during a sales preparation differed significantly between colts and fillies.
“This, along with an increasing body of evidence, suggests that the early conditioning environment may have a role to play in the future training and racing ability of racehorses.”
CF Bolwell, CW Rogers, NP French & EC Firth (2012): Risk factors for interruptions to training occurring before the first trial start of 2-year-old Thoroughbred racehorses, New Zealand Veterinary Journal, 60:4, 241-246