Estimation of Breed Effects on Litter Traits at Birth in Yorkshire and Landrace Pigs

The purpose of this study was to estimate breed effects on litter traits at birth in the Yorkshire and Landrace breeds at a commercial swine farm in central Thailand. A total of 14,097 litters from 2002 to 2006 were analyzed using a GLM procedure. The least squares means analysis showed that the mating group between Landrace sows and Yorkshire boars had a significantly (P < 0.05) larger number of live piglets, of heavier weight than purebred piglets. The crossbreeding between the Yorkshire and Landrace breeds resulted in a lower number of mummified and stillborn piglets. Estimation of breed effects found that the effect of the Landrace sows was highly significant (P < 0.01) on the total number of piglets born, number of piglets born alive, number of mummified piglets and litter weight. The breed effect of the Landrace boars was significant (P < 0.05) on the total number of piglets born and highly significant (P < 0.01) on the number of mummified piglets. Heterozygosity coefficient of piglets was highly significant (P < 0.01) increasing the number of piglets born alive (0.30 pigs/litter) and litter weight (0.23 kilograms/litter) while decreasing the number of stillborn piglets (0.16 pigs/litter).