Genetic factors determining food intake in growing pigs : a review

Abstract

The aim of this paper is to investigate the different genetic factors that influence feed intake, previously to study the possible inclusion of a feeding behaviour criterion in the selection objective. Breed is an important souce of variation of feed intake (differences of 10 to 20%). In addition, breed could influence meal characteristics (frequency, size, duration). Heterosis estimates for daily feed intake (5 to 10% of the parental mean) are similar to those reported for growth rate and feed efficiency. Feed intake differences between the three genotypes at the Hal locus range from 5 to 15%. The average of estimates for feed intake heritability in real ad libitum feeding conditions is 0.32. The average genetic correlations between daily feed intake on the one hand, and average daily gain, food conversion ratio and carcass lean content on the other hand, are around 0.75, 0.40 and -0.45, respectively. The possible consequences of including appetite in the selection objective are discussed on the basis of these average genetic parameters.