Residual feed intake.

Abstract

This chapter reviews residual feed intake (RFI) in the context of its potential use for farm animal genetic improvement aimed at reducing the feed cost of production. Evidence for phenotypic and genetic variation in RFI is presented. Causes of variation in the biological processes (digestion, metabolism, thermoregulation and physical activity) likely to contribute to differences in RFI are also explored. The consequences of selection for low RFI are reviewed, with an emphasis on favourable and potentially unfavourable outcomes in terms of farm animal productivity and profitability.