Linear and temporal changes in the trot of 2-year-old Thoroughbred racehorses in relation to early exercise and race training

Associations between yearling exercise and interruptions during race training in Thoroughbred racehorses

OBJECTIVE

To investigate the effect of exercise during yearling sales preparation on the risk of interruptions during training in Thoroughbred racehorses.

ANIMALS

114 Thoroughbred racehorses.

PROCEDURES

Information regarding the daily exercise of yearlings during sales preparation was obtained prospectively from a convenience sample of stud farms. Yearlings were followed to entry into race training, and subsequently, daily training information was recorded until the end of the racing season. Competing-risks survival analysis was used to model time from entry into race training to voluntary training interruption (no known condition or disease identified) and time from entry into race training to involuntary training interruption (due to presence of a condition or disease) occurring before the first trial (practice race for education). Total hand walking time and mechanical walker time accumulated during sales preparation were the main exposures of interest.

RESULTS

82 of 114 (71.9%) horses had an interruption before the first trial; 65 (79%) interruptions were voluntary, and 17 (21%) interruptions were involuntary. Increased total hand walking time was significantly associated with decreased risk of voluntary interruptions, whereas longer cumulative distances at a canter were significantly associated with decreased risk of involuntary interruptions.

CONCLUSIONS AND CLINICAL RELEVANCE

Results identified an association between early exercise during sales preparation and decreased risk of voluntary interruption and increased risk of involuntary interruption during training of 2-year-old Thoroughbred racehorses. Further investigation into the effects of early exercise on racing performance is needed, but results have indicated that there may be an opportunity to modify early exercise programs.

Proactive Management of the Equine Athlete

Simple Summary

The athletic career of a horse is relatively short. Career length can be positively influenced by the trainer and the age at which the horse starts competition. There are opportunities for a team approach of health professionals and changes in management to improve functional/competition life. The ability to improve the tolerance of the tissue to exercise load via the introduction of early exercise, which reflects the horse’s evolutionary cursorial lifestyle, could provide a proactive mechanism to attenuate injury risk.

Abstract

Across many equestrian disciplines the median competition career of a horse is relatively short. One of the major reasons for short career length is musculoskeletal injury and a consistent variable is the trainer effect. There are significant opportunities within equestrian sport for a holistic approach to horse health to attenuate musculoskeletal injury. Proactive integration of care by health professionals could provide a mechanism to attenuate injury risk and the trainer effect. However, the limited data available on current exercise regimens for sport horses restricts interpretation of how management and exercise volume could be modified to reduce injury risk. Early exercise in the juvenile horse (i.e., pre weaning) has a positive effect on stimulating the musculoskeletal system and primes the horse for an athletic career. The early introduction to sport competition has also been identified to have a positive effect on career length. These data indicate that management systems reflecting the cursorial evolution of the horse may aid in attenuating loss from sport due to musculoskeletal injury.