Genetic parameters of British Landrace bacon pigs

Abstract

SUMMARYGenetic parameters were estimated among 26 traits in British Landrace bacon pigs. The data involved 2,296 pigs from 250 boars tested at the five British national pig progeny testing stations from 1959 to 1961 inclusive. Separate analyses were performed for each sex and for the litter totals, adjustments being made to the data for differences among periods within stations and for differences in age at start of test and in weight at slaughter. The genetic parameters were estimated from the sire components in a conventional hierarchical analysis of variance.Estimates of heritability and genetic and phenotypic correlations among the 26 traits are presented and discussed. The parameter estimates were in very good agreement with figures obtained in a previous analysis with Large White pigs. They indicate that a large part of the variation and covariation among the 26 traits is genetic in origin, and the traits involved would change in response to selection. Moreover, with regard to their concurrent improvement there were no serious antagonisms in the genetic relationships among the traits studied. There was however, evidence of an interaction of sire and sex of progeny for nine of the 26 traits.A principal component analysis was used in an attempt to summarise the correlations among the 26 traits. The first two components gave a reasonable fit to the correlation pattern and these were associated with fat depth, measures of muscling and dressing-out percentage.