Genetic Analysis Of Growth Traits In Luzhong Mutton Sheep

In recent years,there has been a lot of research on mutton sheep at home and abroad,but there are few studies on the estimation of genetic parameters of mutton sheep growth traits.For this reason,in this study,on the basis of collecting data on the production performance of Luzhong mutton sheep,this study is the first time to carry out genetic research on the growth traits of Luzhong mutton sheep.The evaluation provides theoretical guidance and scientific basis for the formulation and optimization of future breeding programs of Luzhong mutton sheep,and accelerates the process of genetic improvement of Luzhong mutton sheep.The results of the study are as follows:(1)The effects of birth year,birth season,and sex on 7 growth traits of Luzhong mutton sheep at the birth,3 month of age,6 month of age,one year old,and adult stages were analyzed by least squares analysis of variance.Birth year had highly significant effects(P<0.01)on 7 growth traits of Luzhong mutton sheep at the birth,3 month of age,6 month of age,and adult stages,and birth year had a highly significant effect(P<0.01)on body weight,body height,chest girth,chest width,chest depth,and pipe girth at one year old stage.Birth season had a highly significant effect(P<0.01)on body weight,body length,chest width,and chest depth at the birth stage;a highly significant effect(P<0.01)on body weight,body height,body length,chest girth,chest width,chest depth,and pipe girth at the 3 month of age stage;a highly significant effect(P<0.01)on body weight,body height,chest girth,chest width,chest depth,and pipe girth at the 6 month of age stage;a highly significant effect(P<0.01)on body weight,body height,body length,chest girth,and chest width at the one year old stage;and birth season had a highly significant effect(P< 0.01)on body length at the adult stage.Sex had highly significant effects(P < 0.01)on 7growth traits of Luzhong mutton sheep at birth,3 month of age,6 month of age,one year old,and adult stages.(2)For the estimation of variance components for each trait in Luzhong muttont sheep,the non-genetic factors affecting each growth trait in Luzhong mutton sheep were identified,and the least squares ANOVA results with significant effects were used as the basis for the estimation of variance components in this chapter.The genetic parameters of 7 growth traits were estimated by DMU software for each growth stage of Luzhong mutton sheep,and the results showed that the heritability of growth traits at the birth stage ranged from 0.05 to 0.23;the heritability of the traits in the range of 0.10～0.37 at 3 months of age belonged to medium to high heritability;the heritability of growth traits in the 6 month of stage of Luzhong mutton sheep ranges from 0.09 to0.45;the heritability of growth traits at one year old stage of Luzhong mutton sheep ranges from0.06 to 0.60;the heritability of adult stages in Luzhong mutton sheep ranged from 0.20 to 0.59,which belonged to middle to high heritability.(3)The analysis of phenotypic trends and genetic trends of growth traits in each growth stage of Luzhong mutton sheep showed that the phenotypic trends and genetic trends of growth traits in each growth stage of Luzhong mutton sheep were not the same.When developing animal breeding programs,the breeding objectives of the population should be fully considered,and only by predicting accurate genetic change trends can an effective and reasonable breeding program to improve the population genetic structure of Luzhong mutton sheep.In conclusion,this study analyzed the factors influencing growth traits at different growth stages of Luzhong mutton sheep,estimated the genetic parameters of growth traits at each stage,and analyzed the genetic trends and phenotypic trends of growth traits at each stage,which provided a theoretical basis for the selection and breeding of Luzhong mutton sheep thereafter.