Breeding And Crosses Of Large White, Landrace And Duroc

the performances, reproducation and carcass traits of Yorkshire Landrace & Duroc were analysed by phenotype index method, mult-trait animal model Best Linear Unbiased Prediction(BLUP) and single-trait BLUP method of GBS software, the synthetical breeding vaule and single trait Estimated Breeding Value (EBV) from 1999 to 2003 were genetic estimated; the influence of selection on finish, carcass traits, meat quality and body conformation were also analysed; both the influences of ESR, FSH- P gene on litter size and H-FABP gene on meat quality of three-way crosses were studied. The results were as follows:1 synthetical indexes by mult-trait animal model BLUP method1.1 The genetic trend of patrilineal index in Yorkshire were 99.10, 99.15, 101.39, 104.57, 108.70; and that in Landrace were 98.02, 99.14, 102.41, 103.33, 106.96; that in Duroc were 99.20, 96.81, 101.7, 103.74, 103.89.1.2 The genetic trend of matrilineal index in Yorkshire and Landrace were 101.20, 101.88, 103.41, 103.78, 103.51, 104.62 and 99.09, 107.04, 105.27, 108.61, 107.86, 107.52 respectively.2 The genetic trend of single EBV by single trait animal model BLUP method.2.1 The days get 100 kg weight: that of Yorkshire, Landrace and Duroc canidate pigs reduce 19.53, 15.70 and 19.80 days respectively from 1999 to 2003, and their improvement of EBV were 2.95, 2.58 and 2.23 days respectively.2.2 Backfai thickness: that of Yorkshire, Landrace and Duroc canidate pigs reduce 0.46, 0.55, 0.59 mm respectively from 1999 to 2003, and their improvement of EBV were 0.12, 0.15 0.13mm respectively.2.3 Average litter size: that of Yorkshire and Landrace first fetation sow increase 0.19 and 0.54 respectively from 1997 to 2002, and the number were 0.35and 1.05 respectively in multiparous sow.and the improvement orf EBV were 0.03 and 0.05 respectively.3 The effects of finishing and cross3.1 Finishing trait: the ADG of Yorkshire, Landrace, Duroc, Landrace X Yorkshire,Yorkshire X Landrace and Duroc X (Landrace X Yorkshire) improved 19. 6%, 25.6%, 31.8%, 33.5%, 11.8% respectively from 2001 to 2003; their feed conversion showed significant trend of improvement.3.2 Carcass and meat quality trait: The laen meat percentage of finished pigs in Yorkshire, Landrace, Duroc, Landrace X Yorkshire, Yorkshire X Landrace and Duroc X (Landrace X Yorkshire) improved 1.70, 4.80, 3.70, 4.0, 2.60, 8.6 percentage respectively from 2001 to 2003; and the backfat thickness decreased 0.6, 4.1, 3.3, 6.0, 10.0 7 & 8.8mm respectivelyly. Their meat colour and cooking losses got some improvement.4 the body conformation got significant of improvement, especially the hoof, rump and ham of Yorkshire and Duroc became more strong, chubby and uniform, the Denmark line Landrace's shortcoming of coarse head and large jowl were solved and its hoof and rump also improved.5 The effects of ESR , FSH B gene5.1 The effects of ESR gene on litter size of Yorkshire and Landrace were not significant.5.2 The effect of FSH B gene on litter size of Yorkshire was significant. The genotype BB had higest litter size(10.42), that of genotype AA and AB were 9.72 and 10.0 respectivelyly, but the genotype AA had highest phenotype in Landrace.6 The intramuscular fat at Hae locus of H-FABP gene had significant model effects ( P <0.01 ); the genotype dd had very significant effects on deposit of intramuscular fat...