Discussion Of The Selection Method On Wanxi White Pig And Analysis Of Its Effect

Combined use of Aggregate selection index based on the breeding values estimated by multiple traits animal model BLUP and DNA marks assisted selection to select Wanxi white pig. Days to 100kg body weight, backfat thickness at 100kg body weight and number of piglets born total were the main selection traits. Slaughter test was carried to measure meat quality traits at every generation. Using GBS soft to estimate breeding values, to construct Aggregate selection index and to do genetic analysis. Checking HAL, FSHβ ESR gene polymorphisms and analyzing the relationships between FSHβ ESR gene and little size traits. Concluding the selection effects on the previous three generations of Wanxi white pig. In addition, analyzing the correlations between carcass traits and meat quality traits , carrying study on measuring backfat thickness and loin eye muscle area in live pigs by B-mode ultrasound machine. Results are that:(1) Separation and recombination also happened at any trait in the first generation of Wanxi white pig, so genetic foundation was established for the selection of new pig breed with the merits of Huai pig and foreign pigs. The results of genetic analysis showed that rather obvious effect had been taken on combining high reproductive capacity of Huai pig with fast growth rate, high lean percentage of foreign pigs in Wanxi white pig by the Aggregate index selection.(2) The effect of FSH β gene on number of piglets born total of first parity in Wanxi white pig was significant in the pilot study, but it should be prudential to use FSH β gene as a mark for the selection of litter size traits and an in-depth study should be carried on. The frequency of n allele of HAL gene was 0.11 in the second generation of Wanxi white pig, so it is possible to get full rid of n allele in Wanxi white pig in the near future. ESR gene had no significant effects on litter size traits in this analysis.(3) Slaughter tests showed that the meat quality of the second generation of Wanxi white pig was better than that of the previous two generations and PH₁, Napole yield were significantly improved. Rather obvious effect had been taken on the white hair color trait of Wanxi white pig by eliminating pigs with black spot on their skin in the previous two generations. Obvious changes had happened on body size traits and splanchna traits for the selecton of production traits tested and DNA marks, assessment of figure assisted.(4) Study on the selection methods of meat quality traits was suggested, because correlations between carcass lean percentage and most of meat quality traits were significant and opposed. B-mode ultrasound machine should be prior to A-mode ultrasound machine, because the former gave a better prediction of carcass lean percentage than the latter.