Early Genetic Parameter Estimation And Evaluation In Alpine Merino Sheep Using ASReml

For the improvement of Alpine Merino Sheep breeding and complete structural construction,optimization of the current breeding program,and improvement of the genetic parameters of early growth traits estimation and genetic evaluation program is imminent.Based on ASReml software combined with BLUP animal model method,this study systematically compared and analyzed the early growth trait identification data of 20057 Alpine Merino Sheep from 2003 to 2015,and created different BLUP animal models with early growth traits.The genetic traits of early growth traits,genetic correlation,phenotypic correlation,and individual sports value were constructed.The comprehensive breeding value model of the target traits was constructed.The annual inbreeding coefficient of the population was estimated and an early genetic parameter estimation and genetic assessment method was established.The improvement of breeding of Alpine Merino Sheep has laid a solid theoretical foundation and technical support.Based on the establishment of a fixed effect model,the non-genetic factors(fixed factors)affectingthe early growth traits of Alpine Merino Sheep were tested for significance using ASReml software.The results of variance analysis showed that the bloodline,sex,type of birth,year of birth,mating month,birth month,flock.The interaction effect between non-genetic factors and the early growth traits of Alpine Merino Sheep was extremely significant(P<0.001).Using ASReml software combined with BLUP animal model method,fixed effect and 20057individual samples,four BLUP animal models for estimating the genetic parameters of early growth traits of Alpine Merino Sheep were created based on the different random effects of each model,and random effects in different models were performed by AIC and LRT.Analysis and comparison showed that the best animal model for estimating the genetic parameters of early growth traits in Alpine Merino Sheep is a BLUP animal model that contains two random effects of additive genetic effects and maternal genetic effects.Based on the best BLUP animal model,the heritability,genetic correlation,phenotype correlation,and individual sports value of the early growth traits of Alpine Merino Sheep were estimated.The average inbreeding coefficient of Alpine Merino sheep from 2003 to 2015 was 0.01273%,and there was no inbreeding depression.According to the early Alpine Merino sheep breeding objectives,constructed by birth weight,weaning weight,weaning staple length and Average daily gain for early comprehensive breeding objectives of breeding value evaluation model:I_i=15b_i+24w_i+100s_i+3a_i.The phenotype and genetic trends of the early growth traits of the Alpine Merino Sheep were evaluated,and the genetic parameter estimation and genetic evaluation methods for the early growth traits of the Alpine Merino Sheep were established.The impact of different datasets and fixed-effects combinations on the estimation of genetic parameters for early growth traits of Alpine Merino Sheep was found to be independent of the effects of fixed effects when the interaction effects between fixed effects were not considered.The heritability of each trait estimated by the effect was considered;the heritability of the maternal effect estimated after interaction effects between fixed effects was slightly higher than the estimated maternal effect heritability when interaction effects between fixed effects were not considered.At the same time,it is found that with the decrease of the amount of data,the effect of fixed effect on the estimation of genetic parameters increases gradually,and the error increases and the estimated value of genetic parameters is high.On the contrary,with the increase of the amount of data,the influence of fixed effect on the estimation of genetic parameters is gradually reduced,the error is reduced,and the estimated value of genetic parameters is low.The results of this study will provide a reference for the accurate estimation of genetic parameters and genetic evaluation for early growth traits of Alpine Merino sheep by considering the characteristics of the traits,population genetic structure and environmental conditions.