Effects of racetrack exercise on third metacarpal and carpal bone of New Zealand thoroughbred horses.

This study examined how racetrack exercise affected the bone density of young thoroughbred horses. The researchers found that regular exercise substantially increased the bone density in certain areas, providing valuable data on how training shapes skeletal development in these animals.

Research Overview

The research was aimed at assessing the impact of regular exercise on the bone density of thoroughbred horses. Focusing specifically on the third metacarpal bone and the carpus (wrist), the study examined seven fillies that were stood upon a daily training regime and compared them with seven fillies that were allowed free exercise. The research took place over a 13-week experimental period at a typical New Zealand racetrack.

Methodology

• The horses were put on a typical New Zealand flatrace training regime and exercised 6 days per week for up to 13 weeks.
• During the day, the horses were confined in 4x4m sand yards and were kept in stables at night.
• The bones of the horses were studied post-experiment using a CT scanner.
• Images of the carpus and the distal third metacarpal bone (Mc3) were examined. The researchers focused on specific areas of interest and determined the mean tissue density equivalent (Houndsfield Units).

Findings

• The results indicated a significant effect of racetrack exercise on bone density particularly in the dorso-distal aspect of the radius and the dorsal aspect of the radial and third carpal bones, as well as in the palmaro-distal subchondral bone of Mc3.
• Differences were also seen between the horses’ right and left legs, possibly due to the horses being trained in one direction around the track.
• The mean tissue density in the Mc3 epiphysis of the exercised group was 36.8% greater than the non-exercised group.

Implications

The study has shown that the bone response to exercise is both quick and considerable. This underlines the importance of using non-invasive diagnostic aids to ascertain when these tissue density changes occur during the training. Understanding this may help in improving training regimes and monitoring horse health and performance.