Effectiveness of a selection based on aggregate genotypes from the viewpoint of economic value in a closed herd of swine

A selection examination of a closed herd of Landrace swine was carried out in order to simultaneously improve reproduction and meat production triats. We obtained the following results from analyses up to the fifth generation. With daily gain (DG), back fat thickness (BF), total number of piglets born (TNB), and litter weight during weaning at 3 weeks of age (LW) as the selected traits, an estimated breeding value based on the best linear unbiased prediction (BLUP) method animal model was determined using an aggregate genotype calculated from the economic weight attained from a trial management of the given pig farm. The average phenotypic value of DG, BF, TNB, and LW in the fifth generation breed was 957 g, 1.79 cm, 11.8 heads, and 55.3 kg respectively. The aggregate genotype at the fifth generation became at +54,000 yen (this breaks down to DG: 33,980 yen, BF: 0 yen, TNB: 12,840 yen, LW: 7,22O yen). The findings of these genetic improvements resulted in an expected increase in profitability. The average breeding value of DG, BF, TNB, and LW for the fifth generation breed was +115 g, 0.0 cm, +0.40 heads, and +3.3 kg respectively, figures which signal favorable improvements in both reproduction and meat production. These results indicate the efficiency of a selection based on aggregate genotypes from the viewpoint of economic value.