Identifying bulls superior for net feed intake, intramuscular fat and subcutaneous fat

Abstract

The presence of positive genetic correlations between Net Feed Intake (NFI) and live animal fatness traits implies that continued selection against NFI (for improved feed efficiency) could be accompanied by a reduction in fatness. Findings are inconclusive on the correlation between NFI and intramuscular (or marbling) fat. The greatest potential financial benefits from lowering feed intake accrue in the feedlot sector, so selection for lower NFI should be carried out in conjunction with careful monitoring of live animal and carcase fatness traits. The genetic correlations are low, and divergent selection for NFI has demonstrated that adequate levels of subcutaneous and intramuscular fat can be maintained while lowering NFI. Industry testing for NFI has identified a number of sires superior for each of these traits.