The Genetic Improvement Of Jianghai Duroc Pigs

The production system of Duroc, Landrace, Large White crossbred breeding has become the dominant mode of pig industry. As a terminal sire line, the genetic contribution of Duroc to DLY is 50%. On the other side, the genetic merit of a Duroc boar can be blew up hundreds to thousands times by AI. Thus Duroc should be attached much more importance than Landrace, Large White.Weifang Jianghai breeding company is now a key national pig breeding farm and a national standardization model farm, which has been formed a Duroc-based high-quality nucleus herd. Through years of genetic evaluations of the National Pig Improvement Program, the breeding index reached a good level, showing good characteristics of tall and strong body, fast growth rate, thin backfat thickness higher lean meat percentage et al.To further improve the Jianghai breeding system, accelerate the pace of genetic improvement, and enable enterprises to achieve greater economic efficiency, we performed a series of research on the problem of Jianghai Duroc breeding system.First, age at 100 kg and backfat thicknes are only the main measured traits before2012, which cannot solve the problem of slow early growth and effective genetic evaluation of lean meat percentage. To solve this problem, we determined the breeding objectives of the main and auxiliary selection traits based on production performance of current herds, Latest progress and research status of genetic evaluation. We researched and made Jianghai paternal index(JHsi) and Jianghai maternal index(JHmi). Especially for the weighted problems of the JHsi and JHmi,we derived the index based on the breeding importance. We also wrote the relevant analytical procedures and assisted Jianghai Duroc to carry out selection and mating.Second, despite a lot of Jianghai body size traits were measured, the measurements are not well used in genetic evaluation and selection because ofthe lack of correction coefficients and corresponding selection index formula. In view of this, we combined with China’s actual situation and foreign experience, and rebuild the Jianghai Duroc’s body conformation assessment system and body index.