Analysis of competition performance in dressage and show jumping of Dutch Warmblood horses.

The research examined factors influencing the genetic evaluation of Dutch Warmblood horses‘ performance in dressage and show jumping. It found that rider effect, censoring and preselection of data had varied impacts, with rider effect being particularly important, and both performance types proving to be heritable.

Introduction

• The study investigated aspects impacting the genetic evaluation of Dutch Royal Warmblood Studbook (KWPN) horses based on their dressage and show jumping performance.
• Typically, the highest score achieved in competition is used to appraise a horse’s genetic ability of performance.
• The researchers aimed to measure the effects of certain factors on this genetic analysis. These factors include the rider’s effect, censoring (where some data points are not fully observed or tracked), and preselection of data.

Rider Effect

• Different models including rider effect were evaluated.
• Results indicated that the performance in dressage and show jumping is indeed affected by the rider, making it crucial to account for the rider’s influence in the genetic analysis.

Censoring Impact

• To assess the impact of censoring, or the incomplete tracking of some data points, genetic parameters were estimated in data sets with varying degrees of censoring.
• The study findings revealed that censoring had only a minor effect on the genetic parameter for the highest performance achieved by the horse.

Preselection Effect

• A binary trait was defined (sport-status) based on whether the horse had a competition record or not to analyse the effect of preselection on variance components.
• All horses registered by the KWPN since 1984 were included in a bivariate model with this competition trait.
• Results showed that sport-status has a moderate heritability, indicating that preselection process has a genetic basis.
• However, the study found that the effect of preselection on the genetic parameters was relatively minimal.

Conclusion

• The study concluded that both dressage and show jumping performance are heritable traits in Dutch Warmblood horses (heritability valued at 0.11–0.13).
• Rider effect was found to significantly influence a horse’s performance, whereas censoring and preselection had a smaller impact on genetic evaluation.