Estimation Of Genetic Parameters And Analysis Of Factors Influencing The Main Economic Traits Of Pigs In The Danish Line

Estimation of genetic parameters is a prerequisite for successful breeding work.In this thesis,using data on the reproductive and growth performance of a national core breeding farm in Anhui Province for the years 2017-2022,the software was used to analyse the variability of different breeds,litters and mating and farrowing seasons on reproductive traits,and also to analyse the differential effects of different breeds,sexes and farrowing seasons on growth traits;the HIBLUP software was used to estimate the reproductive and growth traits of two breeds of the Dan The genetic parameters were estimated by HIBLUP software for the breeding and growth traits of the two Danish Pigs,and the genetic progress of the Danish Pigs herd from 2017 to 2022 was derived,with a view to providing a scientific and reasonable reference basis for the farm to formulate new breeding plans and for future breeding and feeding management.The results of the trial are as follows:1.The total litter size and live litter size of sows in both breeds were lower in the first litter than in the second,third,fourth,fifth and sixth litters,and the total litter size and live litter size gradually increased after the first litter and started to decrease after the sixth litter.The seasonal factors significantly(P<0.05)influenced the reproductive traits of the Danes,with the total litter size of 14.94 and 14.41 in summer breeding for Danish Yorkshire and Danish Landrace respectively,both significantly(P<0.05)lower than the other three seasons.The number of dead litters,weak litters and mummified litters in autumn and winter were significantly lower than those in summer.Therefore,the performance of Danish pigs is poor in summer breeding and good in autumn and winter.2.The age at 100 kg body weight and the thickness of backfat at 100 kg body weight were significantly(P<0.05)higher in Yorkshire than in Landrace.The age at 100 kg body weight of Dan boars was significantly(P<0.05)smaller than that of sows and the thickness of backfat at 100 kg body weight was significantly(P<0.05)higher than that of sows;the age at 100 kg body weight of Yorkshire and Landrace pigs was the shortest in winter and the thickness of backfat at 100 kg was also the thinnest in winter.3.The heritability of each reproductive trait in the Danish Pigs ranged from 0.018 to0.187,with the highest heritability in both the Yorkshire and Landrace pigs being the litter weight at birth;the genetic and phenotypic correlations between the total litter size,live litter size,healthy litter size and litter weight at birth in the Danish Pigs were all positive above 0.700;the heritability of the Danish pigs was medium at 100 kg body weight,and the heritability of backfat thickness was high.The genetic and phenotypic correlations between age at 100 kg and backfat thickness were both negative.In summary,the factors of litter size,season,sex and breed had significant effects on the reproductive and growth performance of Danish pigs.To improve the accuracy of the estimation,the above four influencing factors were put into the model as fixed effects when estimating the genetic parameters.The results of this trial showed that all the reproductive traits of Danish pigs in this farm were low heritability traits;100 kg body weight per day was a medium heritability trait;100 kg body weight backfat thickness was a high heritability trait.