| The purpose of this study was to compare the lambing condition of the introduced Hu sheep in three breeding enterprises in northern and southern Xinjiang,analyze the influencing factors of birth weight and weaning weight of Hu sheep,and estimate the genetic parameters of these two important early growth traits,so as to lay the foundation for genetic assessment and subsequent breeding of the three breeding units in the future.Season and month were taken as two groups of factors with farm,birth type,gender,and SAS9.2 was used to analyze the influence of each factor on target traits.Using the AIREML method of DMU software combined with single trait animal model,two groups of fixed effects corresponding to two traits were selected to estimate the variance components,and the AIC criterion was used to determine the optimal model.Finally,the genetic parameters of birth weight and weaning weight were estimated and calculated by multi-trait animal model.The results show that:(1)The lambing rates of farm 1(Specialized Cooperative for Farming Farmers of Moyu San bao),farm 2(Saiwai Silver Antelope Breeding Farm in Midong District)and farm 3(Changji Shangpinmeiyang Technology Co.,Ltd.)were 216 %,242 % and 170 %,respectively;the healthy lambing rates of the three farms were 87.80 %,87.15 % and 98.03 %,respectively.The birth weight of lambs from farm 1 and farm 2 was extremely significantly higher than that from farm 3(P<0.01).The coefficient of variation of birth weight of lambs in farm 1 and farm 2 was larger because of the rich type of lambing(including 1～5 lambs)of Hu sheep in two farms,and the type of lambing of ewes in Farm 3 was 1～3 lambs.The weaning time of the three farms was 3 months,2 months and 45 days,respectively.The weaning weight in farm 1 was not collected in this study.The weaning weight in farm 2 was extremely significantly higher than that in farm 3(P<0.01).(2)Farm,birth season,birth month,birth type and gender had extremely significantly effects on birth weight of Hu sheep(P<0.01).The birth weight of lambs born in January was the highest,and was extremely significantly higher than that of Hu sheep born in other months(P<0.01).The birth weight of Hu sheep born in November was the lowest;the birth weight of lambs born in winter was the largest,and the birth weight of lambs born in autumn was the smallest.For the birth type(i.e.,the number of lambs with the same birth),the more the number of lambs with the same birth,the smaller the birth weight of lambs,and the birth weight of Hu sheep showed extremely significant difference among different birth types(P<0.01).Gender showed extremely significant difference in birth weight of Hu sheep(P<0.01).For weaning weight,only farm and birth months have a significant impact.(3)The two groups of fixed effects of birth weight and weaning weight were taken into account by using the single trait animal model.The best combination of fixed effects is determined according to the minimum AIC value.For birth weight analysis,field,birth month,birth type and gender were selected as fixed effects.The results showed that direct,maternal and total heritability were 0.25,0.67 and 0.21,respectively.For weaning weight analysis,selection field and birth month were suitable as fixed effects.The direct,maternal and total heritability were0.76,0.14 and 0.34,respectively.Then,according to the best fixed effect of two traits,the multi-trait animal model was used to calculate.The results showed that the direct,maternal and total heritability of birth weight were 0.25,0.66 and 0.26,respectively.The direct,maternal and total heritability of weaning weight were 0.77,0.17 and 0.35,respectively.In this study,the genetic and phenotypic correlations of the two traits were 0.10 and 0.07,respectively.In conclusion,this study compared the production situation of three Hu sheep breeding enterprises in northern and southern Xinjiang,analyzed the influencing factors of birth weight and weaning weight traits of Hu sheep,and estimated the genetic parameters of the two traits,which provided basic phenotypic data analysis reference for the production management and selection breeding of breeding enterprises in the future. |
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