Genetic analysis of the longevity of French sport horses in jumping competition.

This study investigated the lifespan of competitive sport horses in France, identifying the factors that influence longevity and the potential for genetic evaluation of longevity traits. The researchers found that variables like starting age of competition, success in competitions, and sex had significant effects on the horse’s competitive lifespan.

Overview of the Study

• The study used data from over 209,000 horses born since 1968, competing between 1972 and 2008, with the aim of understanding factors influencing the competitive lifespan of French jumping horses.
• Notably, 22% of the records used were right-censored, meaning the horse’s competitive lifespan ended for reasons other than death, such as retirement from competition.
• The study utilized a discrete survival analysis method, including fixed effects like region and month of birth, year of recording, age at first competition, and performance level.

Key Findings

• All of the fixed effects variables had significant impacts on the horse’s longevity, indicating that these factors should be taken into account when estimating longevity.
• The study found that horses that began competing at a younger age tended to have longer competitive lifetimes, contrary to popular belief.
• Success in competitions also played a significant role in a horse’s competitive lifespan: the less a horse earned through competition, the more likely it was to leave the competition. Geldings without earnings had significantly higher risks of exiting competition.
• The sex of the horse was another influential factor, with mares more likely to be removed from competition for potential use in breeding. Mares had a 1.45 times higher risk of culling compared to a gelding of the same performance level.

Genetic Evaluation

• The study also found a heritability estimate of 0.10 for length of competitive life, suggesting there is a moderate genetic component to longevity in competition.
• Based on these findings, researchers were able to predict breeding values for sires and identified that of 3,303 sires evaluated, 262 were used for breeding in 2008.

Overall, this study provides valuable insights into factors that can impact the competitive lifespan of sport horses and presents a foundation for further investigation into the breeding and management of long-lived sporting horses.