Studies On Optimizing The Breeding Program Of Ningxiang Swine

Through sorting out the breeding and production data of Ningxiang Swine,this paper optimized the breeding scheme of Ningxiang Swine from four parts: formulation of correction formula for the growth traits of Ningxiang Swine calculation of marginal benefit and economic weighted value and simplification of comprehensive breeding value,in order to provide theoretical guidance for the breeding of Ningxiang Swine.The optimization objectives of Ningxiang Swine breeding program are as follows: the number of boars and sows,the service life of boars and the investment period of breeding in Ningxiang Swine breeding group.The Saturation model is the most suitable model for the correction of growth traits of Ningxiang Swine,and the correction formula based on this model is widely applicable.The target traits of Ningxiang Swine selected in this study are: the number of alive born piglets(NBA),the litter weight of alive born piglets(LWB),the number of litter pig at 21 days(NL21),the litter weight at 21 days(LW21),the number of litter pig at 35 days(NL35),the litter weight at 35 days(LW35),the growth and development traits contain the day of Ningxiang Swine grown to 50 kg(AGE50)and the backfat when grown to 50 kg(BF50);Multiple regression method was used to calculate the marginal benefit of each trait of Ningxiang Swine as follows: the number of alive born piglets(NBA): 15.81,the litter weight of alive born piglets(LWB): 1.66,the number of litter pig at 21 days(NL21): 7.86,the litter weight at 21 days(LW21): 0.43,the number of litter pig at 35 days(NL35): 2.08,the litter weight at 35 days(LW35): 0.69,the growth and development traits contain the day of Ningxiang Swine grown to 50 kg(AGE50): 0.95,the backfat when grown to 50 kg(BF50):-6.07,the economic weighted value of corresponding characters obtained by calculating its discount value is: 9.98,1.05,4.79,0.26,1.25,0.42,-0.71,-0.67;On the basis of reducing the workload of breeding and improving the work efficiency without affecting the accuracy,the comprehensive breeding values of the target traits were simplified,and the preserved traits were: the number of alive born piglets(NBA),the litter weight at 35 days(LW35),the growth and development traits contain the day of Ningxiang Swine grown to 50kg(AGE50),the backfat when grown to 50 kg(BF50).Based on the above research results,the breeding scheme of Ningxiang Swine was optimized.It was found that when the number of Ningxiang boars remained unchanged,the more the number of Ningxiang sows,the greater the genetic progress was.When the number of Ningxiang sows remained the same,the more the number of Ningxiang boars,the smaller the genetic progress.With the increase of the age of Ningxiang boars,the comprehensive genetic progress and the genetic progress of each trait decreased,but the breeding cost did not change.Prolonging the investment period of breeding will increase the breeding output,but it will not affect the breeding cost.It will also lead to the increase of the discount value of the target trait and the increase of the economic weighted value.At the same time,the inbreeding increment generated by any combination of the optimization level in the test results is not more than 0.5 %;According to the optimal three factors,the results were as follows: comprehensive genetic progress: 7.1233,breeding cost: 11.31,breeding output:136.59,breeding benefit: 125.28.