Major and minor gene effects on pig traits and profitability

Abstract

A line of pigs was selected for high growth rate and low backfat and a line maintained without selection. The halothane gene was segregating in both lines. Estimates were obtained of changes in growth rate and backfat either by increasing the frequency of minor genes by 5 generations of selection, or by substituting either 1 or 2 halothane genes in place of normal genes.Selection of minor genes gave substantial economic gain resulting largely from heavier carcasses of increased leanness. Substitution of a single halothane gene had a small negative effect on profitability but 2 halothane genes substantially reduced profitability mainly through increased mortality and reduced carcass weight and lean quality (increased PSE).

21st Biennial Conference. 8-12 July 1996. University of Queensland, Brisbane.