Estimation of the genetic correlation between performances at different levels of show jumping competitions in Ireland

Abstract

The purpose of this study was to determine the value of performance at both novice (low) and medium levels of show jumping competition for predicting genetic merit for high level performance ability. Show jumping performances, consisting of 258 526 records from 9956 horses in 11 945 national competitions from 1993 to 1998 inclusive were divided into three levels, namely high, medium and low (novice). For the purpose of analysis, performance at each of these levels was regarded as performance in three different traits. The measure of performance used in the genetic evaluation of show jumping horses in Ireland is obtained by ranking all performances in all competitions. The rank is based on the number of faults incurred and the length of time taken to complete each round of competition. The heritability of performance at these three levels and the genetic correlation between levels were used to estimate the predictive value of performances at the lower levels for genetic merit for high level performance. The genetic correlations between these traits and their heritabilities were estimated using reml vce. The genetic correlation between high and low levels was 0.69 (standard error ( se) 0.07), between medium and low 0.97 ( se 0.02) and between medium and high 0.83 ( se 0.05). The heritability of performance at high level was 0.10 ( se 0.01), at medium level 0.08 ( se 0.01) and at low level 0.07 ( se 0.01). These estimates indicate that low (novice) and medium levels can be useful in predicting an animal's potential genetic merit for high level performance.