The Impact of Horse Age, Sex, and Number of Riders on Horse Performance in British Eventing Horse Trials.

Limited research has been undertaken to determine the impact of horse age, sex, and number of riders on horse performance in British Eventing (BE) horse trials. Improved understanding of this can aid professionals in planning a competition horse's career. To investigate the impact of age, sex, and number of riders on the peak performance of horses at each of the main levels of BE competitions. The best score from each horse competing in BE horse trials in the years 2008-2018 was recorded, and principal component and hierarchical cluster analysis was performed. Basic data analysis was used to identify variables associated with particular better-performing clusters of horses. The interplay of the combinatory variables was then used to map out the trends in career trajectory for horses competing at each level of competition in the best-performing and worst-performing clusters. The peak performance of mares was worse than geldings and stallions at all levels. At Novice to Advanced, stallions did not perform as consistently with multiple riders as geldings. The age at which the best-performing groups peaked was similar for mares and geldings in all classes, although stallions peaked at an older age than mares and geldings at Novice and Intermediate level. All horses were a minimum of 4-years-old at the time of competition, as per BE rules.