The impacts on selection for economic merit of including residual feed intake traits in breeding objectives and of having records available

Abstract

A study was conducted to quantify the separate and combined impacts on selection for economic merit of including residual feed intake (RFI) traits in beef cattle breeding objectives and of having records available. RFI is a trait of interest in numerous livestock species. It was defined here for young animals at pasture (RFI-P), in the feedlot (RFI-F), and in cows (RFI-C). Results showed selection response in total economic merit increased by up to 65% for breeding objectives where RFI-P, RFI-F, and RFI-C were all included. A large proportion of the benefit (more than 50%) came from being able to include RFI traits in the breeding objective, suggesting major benefits may be realised even where a suitable industry measure is not yet available. Residual feed intake should be considered in breeding objectives and selection where parameter estimates are available. Estimates of genetic variance are among those most needed for RFI-C, and are likely to need to be understood in cows that are approximately maintaining or even losing weight.