Genetic Linking of Pig Farm, Testing Station and Artificial Insemination Centre

Growth rate and fat records were analysed from four breeding centres, three farms and a boar testing station. The centres were genetically linked through the use of common AI sires (formal) and other breeding animals (informal). Practical difficulties were experienced in achieving satisfactory levels of formal linkage. Linkage placed the mean breeding merits of the different breeding centres in the correct relativity so breeding values were comparable across centres. Heritability estimates for growth rate and fat in the station were more than twice as high as those on farm and the genetic correlations between these traits were favourable in the station but unfavourable on farm. Correlations between station and farm performance were high. Station testing should give higher response than farm testing to a given amount of selection in farm profit.