Study On The Factors Affecting Reproductive Performance Of Liangshan Pigs And Genetic Parameters Calculating Of Main Reproductive Traits

In order to study the factors affecting the reproductive performance of Liangshan pigs and to calculate the genetic parameters of their main reproductive traits,the Leshan Mabian Jinliangshan Agricultural Development Co.,Ltd.Liangshan pig breeding farm was collected and organized from the establishment in 2012 to 7 years in 2018.The reproductive data of 1023 purebred Liangshan pigs were analyzed,and the factors affecting the reproductive performance of Liangshan pigs were analyzed.The genetic parameters of each reproductive performance were calculated by ASReml software.The main results are as follows:1.Liangshan pig maintains the moderately low reproductive performance of typical southwestern pig breeds and has a significant annual effect.The overall performance is that the overall performance of reproductive performance increases with the year.Among them,the total number of litters has increased from 8.88 in 2012 to 9.37 in 2018,and the number of live births has increased from 8.13 to 8.58.2.The reproductive performance of Liangshan pigs showed a significant fetal effect.The reproductive performance of the first fetus was the worst,and then gradually increased.The reproductive performance of the fifth fetus was the best,and the traits such as litter size,live litter size,newborn litter weight,and primary weight were significantly higher than the first fetus(P< 0.05).Although some of the traits of the sixth child have a tendency to decline,they have not reached a significant level,indicating that Liangshan pigs can also extend the use of the parity.3.Seasonal effects had significant effects on the reproductive performance of Liangshan pigs.The total litter size in summer was significantly higher than that in winter The number of live litters and litter weight were significantly higher than other seasons.In general,the reproductive performance of Liangshan pigs is best in summer.4.The phenotypic parameters of Liangshan pig reproductive performance were found to be large,indicating that the coefficient of variation of all reproductive traits was large,indicating that the Liangshan pig population maintained a good genetic variability,and the overall reproductive performance had a large breeding room.5.The results of calculating the heritability and repetitive force of each reproductive trait of Liangshan pig showed that the repetitive force of all reproductive traits was greater than the corresponding heritability,the heritability ranged from 0.11 to 0.28,and the repetitive force was between 0.12-0.47.The results were basically consistent with the research reports of pig breeds in other places in China,and the reproductive traits were generally low heritability traits.6.The genetic correlation and phenotypic correlation between reproductive traits showed that the phenotypic correlation and genetic correlation between different traits were different,the phenotypic correlation coefficient was between-0.16 and 0.84,and the genetic correlation coefficient was between-0.003 and 0.998.