Genetic trends in performance traits of Large White, Landrace and Duroc swine breeds

Data of Large White (LW), Landrace (LD) and Duroc (DU) swine were used to estimate the genetic trends for adjusted weight at 70-days old (AW70) in kg, average daily gain (ADG) in g and backfat thickness (BT) in cm. The genetic trends were estimated by regression of the averages of trait genetic values in function of the animal birth year. The estimates of the genetic trend for AW70 (LW = -0.22; LD = -0.24; DU = -0.57) were negative, possibly due to a greater emphasis given in the selection process for ADG and BT and to the correlations between these traits. The estimates of the genetic trend for ADG (LW = 14.11; LD = 9.8 1; DU = 2.75) and BT (LW = -0.07; LD = -0.05; DU = -0.04) are in accordance with the objectives of the genetic program and with the existing correlation between these traits as well.