Genetic relationship between free movement and under rider gaits in young Pura Raza Española horses

Abstract

The Pura Raza Espanola ˜ (PRE) horse is an autochthonous Spanish horse characterized by its versatility, mental balance, and its balanced conformation, which makes it suitable for sports disciplines such as dressage. The aim of this study was to determine the genetic correlation between the quality of natural gaits in young horses, when the horse is evaluated in the Basic Aptitude Test (free movements, FM) and during dressage competitions (functionality tests and gaits under rider, UR). A total of 37,822 and 2730 PRE horses were evaluated for FM and UR, respectively, of which 1023 horses had records for both (coincidence animals). Genetic parameters were estimated using VCE software. Effects were included in the final model according to significant results in analyses of variance (GLM). For FM and UR, the genetic model included age as a linear covariate, gender, coat colour and stud size as fixed effects, and for UR, the rider and permanent environmental effects were also included as random effects. The pedigree file information included a minimum of 4 generations: 88,558 horses (FM), 13,837 horses (UR) and 9072 horses (coincidence animals). Heritabilities were estimated for the two data sets (FM and UR) and, for the coincidence population, heritabilities and genetic correlations were also estimated. The heri tability for walk, trot and canter (FM) were 0.20, 0.22, 0.22, while for UR they were 0.26, 0.31, 0.33, respec tively. For coincidence animals, the heritability for walk, trot and canter (FM) were 0.43, 0.33, 0.22, while for UR they were 0.23, 0.11, 0.10, respectively. The genetic correlations between FM and UR traits were high and positive; 0.49 for walk, 0.61 for trot and 0.54 for canter. The genetic parameters obtained highlight the possi bility of preselecting gait traits in young horses destined to participate in sporting competitions.