Multi-trait animal model estimation of genetic parameters for morphometric measurements in the Murgese horse breed

The Murgese is a baroque-type horse breed from Southern Italy that is currently experiencing growing interest both at local and international level. The aim of the present work was to investigate the morphological evolution of withers height (WH), chest girth (CG) and cannon bone circumference (CBC) over the last four decades by using linear regression analysis, and to use a multiple-trait animal model with fixed effects (herd, sex, birth year) to estimate genetic parameters for the above traits in the Murgese horse population. A significant increase of WH (only in males), and decrease of CG and CBC over the considered period was observed, though no remarkable trend in genetic gain was observed for the above traits. Hereditability estimates were 0.27 (WH), 0.31 (CG) and 0.24 (CBC). Genetic correlations ranged 0.641 (CG×WH) to 0.709 (CG×CBC). The obtained results suggest that phenotypic selection has not had so far a large impact on the Murgese morphology, whose evolution over the last four decades seems more likely attributable to improvement in management practices. According with the obtained heritability estimates and the favorable genetic correlations, there is ground for the application of quantitative genetic selection for the considered morphometric traits.