Genetic analysis of residual feed intake, feed conversion ratio and related growth parameters in broiler chicken: a review

Major feed ingredients, like maize and soya, and land resources are used by both humans and animals, causing competition and affecting costs. To make the poultry industry profitable, it is important to prevent wastage of feed, and feed efficiency is therefore important. Residual feed intake (RFI) and feed conversion ratio (FCR) are two measures of feed efficiency used to assess production efficiency. This review describes a different aspect of feed efficiency measures and how their correlated traits affect poultry production. Bird selection, based on RFI and FCR at the 5th week or market age, is effective since both are low to moderately heritable (heritability estimates of RFI and FCR are 0.21-0.49 and 0.11-0.44 respectively). Both RFI and FCR selection results in reduced feed intake without compromising growth rate. Selection based on RFI is better in comparison to FCR for improving feed efficiency, as it is a trait independent of the maintenance energy requirement of an individual bird. Bird with low RFI value can be expected to have better feed efficiency and can be helpful in lowering the cost of poultry production.