Relationship between conformation trait and gait characteristics in Spanish Purebred horses

In the breeding program of breeds such as the Pura Raza Español horse, selection by gait quality is of great interest because of their use for dressage performance. However, biokinematic analyses are expensive and data processing is time consuming. So, indirect measurements related to movement quality are alternatively used for a precocious selection of the animals. The aim of this study is to estimate the genetic correlations between 13 conformation measurements and 16 biokinematic variables at trot (4 linear, 6 temporal and 6 angular) in order to identify objective selection criteria for locomotion ability. A total of 130 Pura Raza Español horses from 24 studs, aged between 4-7 years old, were measured and their biokinematic variables were obtained in experimental conditions on a treadmill. There were 155 significant genetic correlations between conformation and biokinematic traits. Croup length was the most correlated trait with biokinematic variables at trot (16), and croup width was the least correlated one (7). Forelimb length and forelimb duration were the most correlated with conformation measurements (12), whereas minimal angle of carpus was the least correlated one (5). All the conformation measurements were genetically correlated with biokinematic variables, and through these relationships when trotting, a total of 6 body measurements were selected for the indirect and precocious selection of gait quality, which could be included directly or combined in body indices