Genetic diversity derived from pedigree information and estimation of genetic parameters for reproductive traits of Limousine and Charolais cattle raised in Italy

Abstract

Limousine and Charolais cattle breeds are assuming increasing importance in the Italian beef cattle sector. Indeed, both breeds are involved in a national rural development project. The success of a breeding programme depends heavily not only on the defined breeding objective but also on the selected criteria used to attain it. Data from the Charolais and Limousine Italian Association (born between 1960 and 2017) were used to estimate both genetic parameters and trends for calving interval (CI) and age at first calving (AFC) and genetic diversity. Population structures were investigated through probabilities of gene origin approach whereas variance components estimation was used to obtain breeding values of reproductive parameters. Heritabilities for AFC and CI were 0.24 and 0.03 for Limousine and 0.32 and 0.02 for Charolais, respectively. An increasing genetic trend was observed for AFC. For CI, no significant gains of genetic origin have been verified. In both breeds, pedigree completeness was moderate, and the observed inbreeding coefficient was low. No herd is classified as a nucleus or isolated and they all use external bulls. Heritability for AFC in both breeds suggests possible improvements when selected. Limited improvements are expected for CI by means of a traditional genetic breeding scheme. A reduction in the generation interval might represent a cost-effective solution to increase annual genetic gain. Pedigree analysis suggests population bottleneck in both breeds.HIGHLIGHTS Limousine and Charolais breeds are involved in the national project for the genetic improvement of cattle populations raised in Italy. Genetic indexes will be developed following a genomic approach. This study is preparatory for the implementation of a selective programme of this type. The breeds presented a reduced number of animals in the genetic formation. High ‘bottleneck effect’. Moderate heritability for age at first calving.

Keywords

• inbreeding
• generation interval
• pedigree
• genetic trend
• genetic variability