Selection And Improvement Of Xiangyi Pig Synthetic Line And The Study Of Their Performance

As a big country in pig industry, China takes the pig breeding on a very important position in agriculture system. And consumption of pork is biggest in meat product. Although the scale of pig husbandry has increased substantially, the effentiency of pig production stay at a low level for a long time. Contribution rate of technology advance is low, especially, there is a severe shortage of good breeds. Xiangyi pig synthetic line has the duroc pig as the paternal line Ⅱ, the landrace pig as the paternal line Ⅰ, and the large white pig as maternal line, and cultivated through the open nucleus breeding program, and examined and approved by the committee of livestock and poultry breeds of Hunan province in2006.From2006to2011, we have further selected the three special lines based on the existed populations. The open nucleus breeding program and the strategy of combination of open and close was used. We made the selection and matching through performance measurement, genetic evaluation and conformation scoring to strengthen and improve the genetic stability and performance. After6years selection, the growth performance and reproductive performance were further inhanced. The number multiparity born alive of maternal line pig was increased by0.83, corrected total litter weight of21days increased by3.28kg. Paternity index of replacement pig of paternal line Ⅱ was increased by7.67. the maternal index of replacement pig of paternal line Ⅰ and maternal line were increased by5.40and0.91seperately. Average daily gain of paternal line Ⅱ and paternal line Ⅰ and maternal line and landrace x largewhite and commercial hybrid pig were increased by19g and42.2g and56.82and59g and24.55g separately. The average daily gain of commercial hybrid pig reached873g, feed conversion ratio reached2.32, dressing percentage reached77.48%, eye muscle area were47.75cm2, marbling grade were3.88, and abtained high growth speed, high lean meat percentage, excellent meat quality, and uniform conformation. All special lines and commercial hybrid pig reached a good breeding effect. Popularization of Xiangyi pig synthetic line has a helpful effect to promote the development of regional pig industry.