Estimation Of Genetic Parameters Of Important Economic Traits In Pigs

The variance components,heritability,genetic correlation and other genetic parameters of the main economic traits of the breeding population play an important role in guiding the selection of breeding goals.The genetic parameters are quite different for different genetic backgrounds,such as the British pigs and American pigs.In order to accurately estimate the genetic parameters of important economic traits of pigs with different genetic backgrounds and provide reference for the management and breeding of pig farms,this study used the performance data of pigs from 2012 to 2018 in 8 breeding farms in Hebei as materials,The nature and distribution of the data are used to study the test data,and the method for judging and correcting abnormal data is established.The EXCEL software is used to sample the measured data and the data gradient is set to analyze the influence of the amount of data on the genetic parameter estimation results.Using ASReml-R 4 software combined with BLUP animal model,four groups of the age at 100 kg(d)(AEG100),backfat thickness at 100 kg(mm)(BF100),total number born(TNB),number born alive(NBA),litter weight(LW),gestation length(GL),weaning-to-service interval(WTS)and farrowing interval(FI)for the estimation of variance components and analysis and comparison of heritability and genetic correlation,and the non-genetic factors that affect the traits are analyzed.The findings are as follows:According to the normal growth and reproduction rules of pigs,test scores and related records,the normal range of traits is determined,and the correctness of the data is judged based on the data phenotype analysis and genetic analysis results.A method for judging abnormal performance data is established.The genetic parameters of important economic traits of different pig herds were estimated differently.The estimated heritability of AGE 100,BF100,TNB,NBA,LW,GL,WTS and FI of British Large White pigs are 0.17,0.06,0.015,0.018,0.030,0.155,0.021,0.045;The estimated heritability of AGE 100,BF100,TNB,NBA,LWGL,WTS and FI of British Landrance pigs are 0.08,0.06,0.038,0.050,0.044,0.181,0.068 and 0.018;The estimated heritability of AGE 100,BF100,TNB,NBA,LWGL,WTS,and FI of French Large White pigs are 0.16,0.12,0.098,0.115,0.156,0.322,0.164,and 0.078;The estimated heritability of AGE 100,BF100,TNB,NBA,LW,GL and FI of American Large White pigs are 0.19,0.17,0.066,0.046,0.068,0.210 and 0.054.The heritability of growth traits and reproductive traits of British Large White pig and British Long White pig were lower than those of the other two herds,which may be due to the reduction of genetic diversity caused by breeding,and thus the additive genetic variance is smaller.The growth traits of pigs were significantly affected by the nest effect and the AGE nest effect was greater than the BF nest effect.The results of genetic correlation showed that there was a strong positive genetic correlation between TNB,NBA,and LW,and there was a negative genetic correlation between TNB and GL.There is a positive genetic correlation between WTS and FI,but the genetic correlation between the two traits of French white pigs is weak.FI is negatively correlated with litter traits and litter weight.different amounts of data have an important impact on the accurate estimation of heritability of pig growth traits and reproductive traits.The heritability of the traits tends to be consistent and the estimation of heritability is more accurate as the amount of data increases.After the total number of TNB and NBA were determined to reach 4000,the heritability estimates tended to be the same,while the LW tended to be the same after the measured data amount reached 5 000.The two growth traits began to fluctuate slightly after the amount of data reached 10 000.The following conclusions can be drawn from the above research results:The genetic parameters of important economic traits of pigs differ among different groups,When the valid data reaches the required quantity,it is advisable to estimate the genetic parameters of the population for genetic evaluation.The four groups in this study all meet the data requirements.The heritability of FI is low.It is not suitable for direct selection.The selection of WTS will lead to favorable genetic progress for FI,but the genetic correlation between FI and WTS in different herds varies greatly.In addition,selection of litter traits and LW will not adversely affect FI.