Genetic parameters of feed efficiency and feasibility of selection in Charolais cattle population Dossier: Feed efficiency of beef cattle

Abstract

Genetic selection for feed efficiency is a tool to improve the profitability of beef cattle farms. Until now, a genetic evaluation of this trait was carried out in performance test stations using a complete pelleted diet, which is not widely used on farms. The objective of this study is to confirm if this selection is relevant to improve feed efficiency trait of animals which fed forage or concentrate diet. For this purpose, young bulls fed silage (n=639) and heifers fed forage (n=569) were used as well as the Charolais bulls tested on performance stations (n=4675). Three feed efficiency criteria were used: Residual Feed Intake (RFI), Residual Gain (RG) and Feed Conversion Efficiency (FCE). Genetic parameters were estimated and showed that the three feed efficiency criteria was moderately heritable for both bull populations (from 0.10 to 0.26), low for heifers (from 0 to 0.13). Concerning both bull populations, genotype x environment interaction would exist (0,58±0,37 performance tested bulls and young bulls) and thus, genetic progress would be lower concerning the selection of this trait. Phenotyping on forage-based diets would therefore be an effective way to reduce this interaction. For heifers, the small number of animals and the use of two different diets have limited the accuracy of the estimates (0.50±0.48 with performance tested bulls). Direct or indirect phenotyping of feed efficiency is the key element to make the evaluation sustainable.