Estimation Of Genetic Parameters And Analysis Of Influencing Factors For Reproductive And Growth Traits Of Breeding Pigs

Estimation of genetic parameters is a prerequisite for the pig breeding work,and it is essential for estimating breeding value,predicting genetic progress and optimizing breeding programs.This study was based on data collected from the reproductive and growth traits of Yorkshire,Duroc,and Landrace pigs in a core breeding farm in Shaanxi from 2009 to 2020,using R software to analyze the variance of the influencing factors of the traits and explore the influence of various factors on the performance of breeding pigs in this farm.Furthermore,DMU software was used to estimate genetic parameters of reproductive and growth traits of the three breeds of pigs,which can also lay the foundation for further formulating reasonable breeding programs.The specific research results were as follows:1.Parity had significant(P < 0.05)or extremely significant(P < 0.01)effects on the reproductive performance of the three breeds of sows.Among them,the reproductive performance of sows in 3-5 litters was the best,with the highest total number born(TNB),number of born alive(NBA),number of healthy birth(NHB),and the litter birth weight(LBW).The first litter was the lowest.Although the reproductive performance of 5-6 litters was better than that of the first litter,there were more the number of stillborn(NSB),number of birth dead(NBD)and number of weak birth(NWB).In addition,the gestation length(GL)of 6 litters of the three sows was about 116 days.2.The farrowing year had extremely significant(P < 0.01)effects on important economic traits of Large White Pigs,Landrace Pigs and Duroc Pigs.In 2011,the reproductive and growth performance were the worst.3.The farrowing season had significant(P < 0.05)effects on the reproductive and growth performance of the three breeds of sows.When Yorkshire pigs gave birth in spring,TNB,NBA and LBW were the highest.In winter,Yorkshire and Duroc pigs had fewer NSB,NBD and NWB.The analysis of growth traits also showed that piglets born in winter grew faster,and average daily gain(ADG),age at 100 kg live weight(AGE)and backfat at 100 kg live weight(BF)were better than the other three seasons.4.Gender had a significant effect on ADG,AGE and BF of Yorkshire and Landrace(P<0.05).The ADG,AGE and BF of Yorkshire and Landrace boars were significantly better than sows(P < 0.05).Although Duroc boars had a tendency to be better than sows in growth traits,the difference was not significant(P > 0.05).5.The variance component estimation results showed that the reproductive traits of the three breeds of sows were low heritability traits,and the estimated value was between0.01-0.18.There was a high positive correlation among TNB,NBA,NHB and LBW.GL and TNB,NBA,NHB,NSB,NBD showed a medium to high degree of negative correlation.Duroc’s NSB,NBD and TNB,NHB,LBW showed a high degree of negative genetic correlation.6.The estimated heritability of growth traits was among 0.01-0.11.The phenotypic correlation of the growth traits of the three varieties was weak.Duroc’s growth traits were highly correlated.The genetic correlation between ADG and AGE was-0.82,the correlation between ADG and BF was 0.99,and the correlation between ADG and BF was-0.99.Landrace’s genetic correlation between ADG and ADG was-0.93.In summary,the year,season,parity and gender can be put into the genetic parameter estimation model as fixed effects to improve the accuracy of the estimation.In addition,the results of genetic parameter estimation show that the breeding and growth traits in this farm are low heritability traits.