Journal article

The use of different models for the estimation of residual feed intake (RFI) as a measure of feed efficiency in meat sheep

SA Knott, LJ Cummins, FR Dunshea, BJ Leury

ANIMAL FEED SCIENCE AND TECHNOLOGY | ELSEVIER | Published : 2008

Abstract

The concept of residual feed intake (RFI), in determining differences among animals in converting feed into body tissue, was first raised in 1963. Feed efficiency is typically calculated as a function of liveweight gain (LWG) and feed intake (FI). Historically two versions of the same model were proposed, one where FI was adjusted for liveweight (LW) and LWG, and the other where LWG was adjusted for FI and LW. Variation in LWG or FI could then be partitioned into two parts; that which is expected and can be attributed to differences in FI or LWG; and that which is the residual portion, which is the deviation from the expected value based on regression, and therefore not accounted for by diff..

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