Study On The Current Situation And Countermeasures Of Conservation Of Indigenous Pig Genetic Resources In Sichuan Province

To comprehensively investigate the conservation status of Sichuan indigenous pig breeds,strengthen the understanding of germplasm characteristics and scientifically guide protection and exploitation of Sichuan indigenous pig breeds,this study systematically collect,organize and improve the basic information of 7 Sichuan indigenous pig genetic resources.Meanwhile,this study also analyzed the dynamic process of its population size and production performance.Taking the large population size and the highest degree of industrialization of Neijiang pig as an example,according to the breeding situation of this breed,the genetic variation of its production performance level in the past 30 years is analyzed in detail,which provides theoretical data for evaluating the status of pig resource conservation in recent years in our province.Based on the actual conservation situation of Sichuan indigenous pig breeds,this study also discussed the main problems existing in the conservation process of indigenous pig breeds in Sichuan province,and put forward corresponding countermeasure and suggestion,to promote the conservation and sustainable utilization of indigenous pig breeds in our province.The main results are as follows:(1)Sichuan indigenous pig breeds are rich in genetic diversity,and generally have excellent germplasm characteristics such as strong resistance to stress,good meat quality and strong adaptability.Moreover,Sichuan indigenous pig breeds are widely distributed throughout the province,but each pig breed has its core preference region,showing typical regional characteristics.According to the ecological characteristics of the main producing areas,the 7 original indigenous varieties of Sichuan Province can be divided into plain type(Chenghua pig),hilly type(Neijiang pig and Rongchang pig),mountain type(Yannan pig,Penzhou Mountain pig,Wujin pig(Liangshan pig))and plateau type(Tibetan pig).There are great differences in body shape,body size,coat color and growth and development among different types of pigs.For an instance,Neijiang pig is larger in body size,but Tibetan pig is a typical miniature pig breed.This phenomenon indicate that Sichuan indigenous pigs show low degree of hybridity among different breeds in the history.(2)At present,the population quantity of 7 typical indigenous pig breeds in Sichuan has reached the requirement of quantity in living conservation pattern.So far,there are specialized conservation farm or conservation area established for each indigenous pig breeds respectively.In the recent 3 years,the number of annual stocks,the effective population size,the ratio of male and female,the increment of inbreeding coefficient and so on have been kept within a relatively ideal range.However,the effective population size of Huchuan Mountain Pig(Qingyu Pig)and Wujin Pig(Liangshan Pig)fluctuated greatly in the past 3 years,showing a trend of decreasing in effective population size and increasing in increment of inbreeding coefficient,which should be of great concern.(3)In the past 30 years,the physique and appearance of Neijiang pig have become longer and higher,the meat yield has been improved significantly,the slaughter rate has been increasing year by year((in 1987:67.50%、in 2007:71.78%、in 2013:72.27%),which indicates that the breeding progress was obvious.The difference between male and female pigs become less and less.Compared with the average daily gain in 1987,the average daily gain was improved by 29.63% in 2007.Meanwhile,the reproductive performance of Neijiang sows also increased significantly,especially,the third litter size increased by 1.57 and the average litter size of the first sows increased by 1.31.