Estimating Genetic Change in the Swedish Pig Population by Using Mixed Model Methodology (BLUP)

Abstract

The genetic trends for slaughter pig traits in the Swedish pig population were estimated by using mixed model procedure. The data comprised information on 8730 pigs (5801 Land-race and 2 929 Yorkshire) reared at the two pig progeny testing stations Hermanstorp and Öllsjö, and slaughtered between September 1976 and August 1980. The sires and dams were grouped according to their year of birth. The genetic trends estimated from the constant estimates of these groups differed a lot between sires and dams. The average genetic trends for sires and dams gave estimates lying close to the estimated phenotypic trends. The estimated yearly genetic gains were for average daily gain during test (g): +6.0 (L) and +4.0 (Y), for kg feed/kg gain: -0.032 (L) and -0.031 (Y) and for percentage lean in carcass: +0.40 (L) and +0.58 (Y). Some deterioration of meat quality and shortening of carcasses was noted for both breeds, however more accentuated for Yorkshire.

Key Words:

• Genetic change
• pig testing
• slaughter pigs
• mixed model