[EAAP 2024] Poster EAAP sur l’évaluation de la précocité de développement du Projet Precobeef2

In beef farming, one way to maximize productivity while limiting environmental impact is to select animals that develop more quickly. The maturing rate index, which tracks the proportion of adult weight reached over time, can be used to measure this precocity. A preliminary study revealed that the maturing rate index, estimated using the Brody equation, was moderately heritable. In this study, we assessed implementing genomic selection for this trait in Charolais, Limousin, Blonde d'Aquitaine, Parthenaise, and Aubrac breeds. Weight records from birth to post-weaning from commercial farms and slaughter weights from French national databases were used. For more reliability, only females slaughtered after 4 years of age with at least 4 recorded weights were kept. The final dataset included data on over 460,000 Charolais, 270,000 Limousin, 93,000 Blonde d'Aquitaine, 38,000 Parthenaise, and 7,000 Aubrac females, with respectively 8,000, 2,000, 4,000, 1,000, and 600 genotyped animals. An univariate genetic evaluation was performed using a single-step model with the HSSGBLUP software in order to estimate the breeding values for the maturing rate index. Across the five breeds, the heritability of maturing rate index ranged from 0.22 to 0.25. The genetic evaluation revealed that gaining one standard deviation of the precocity of development genomic index equated to a maturing rate index increase of 9.86% and a reduction of 1.3 months to reach half of adult weight. Routine implementation of this evaluation is anticipated in the near future, offering the opportunity to select the most precocious animals in beef farming. Furthermore, investigating correlations with other key traits targeted for selection is recommended.