Invited review: Disentangling residual feed intake—Insights and approaches to make it more fit for purpose in the modern context

Residual feed intake (RFI) is an increasingly used trait to analyze efficiency in livestock, and some sectors such as dairy cattle, it one of the most frequently traits. Although principle for calculating RFI always same (i.e., using residual a regression on performance predictors), wide range models are found literature, with different predictors, ways considering intake, more recently, statistical approaches. Consequently, results not easily comparable from study another they reflect biological variabilities, relationship between RFI) underlying true also differs. In this review, components equation explored respect processes. The aim decomposition provide better understanding which processes complex contribute significantly individual variability efficiency. intricacies associated term, well energy sinks broken down discussed. Based exploration recent new forms proposed separate terms errors inaccuracies. review considers time period measurement RFI. This key consideration accuracy estimation itself, relationships short-term efficiency, animal resilience, long-term As livestock production moves toward sustainable these considerations important bring bear estimations.