OBSERVATIONS ON GENOTYPE-ENVIRONMENT INTERACTION IN SWINE

Abstract

An experiment was carried out to evaluate the importance of genotype-environment interactions in Canadian Yorkshire swine. Two males and two females from each of four litters by each of four sires were randomly allotted to two feeding and management treatments. One male and one female from each litter were self-fed A.R. feed mixtures in a piggery and the other male and female were self-fed the same feeds on pasture. Weights were taken at 56 and 140 days of age and at 190-200 lb. live weight. Carcass measurements were taken at slaughter.Rate of gain from 56 to 140 days for pasture-fed pigs was significantly lower (P = <.01) than for those fed in the piggery. Pigs fed on pasture were also significantly shorter (P = <.01) than those fed in the piggery. Sire-treatment interaction was significant for loin area (P = <.05) and approached significance for rate of gain from 56 to 140 days (P(=).09), A.R. carcass score (P(=).13), and average backfat thickness (P(=).08). A marked shift in ranking of sires between treatments was noted for loin area, rate of gain, and A.R. carcass score. These results indicate that genotype-environment interactions may exist in Yorkshire swine.