天目多胎羊羔羊期体重性状遗传分析

Genetic analysis of body weight traits in Tianmu multiparous lambs

为进一步提高天目多胎羊的生长性能和育种效率,收集2013-2022年天目多胎羊18 534条断奶前体重数据,分析影响天目多胎羊羔羊期体重性状的非遗传因素,利用DMU软件估计遗传参数和育种值,分析其遗传趋势和表型趋势。结果表明:1)性别、出生年份和出生季节对天目多胎羊羔羊期体重性状均影响极显著(P<0.01);出生类型对断奶前克莱伯比率具有显著(P<0.05)影响,对其他性状具有极显著影响。2)初生重为中等遗传力性状,直接遗传力为0.18±0.03,母体遗传力为0.13±0.02;断奶重、断奶前平均日增重和断奶前克莱伯比率属于低遗传力性状,直接遗传力分别为0.06±0.02、0.06±0.02和0.02±0.01,母体遗传力估计值分别为0.07±0.01、0.07±0.01和0.09±0.01。3)除初生重与断奶前克莱伯比率之间为负的遗传相关与表型相关外,其余各性状间均为正遗传与表型相关。4)初生重的平均育种值整体呈现下降趋势,平均表型值呈先上升后下降的趋势;断奶重的平均育种值与平均表型值均先下降后上升;断奶前平均日增重和断奶前克莱伯比率的平均育种值先下降后上升又下降终上升,平均表型值先下降后上升。5)初生重、断奶重、断奶前日增重和断奶前克莱伯比率的遗传进展分别为-0.013 kg/a、-0.005 kg/a、-0.001 g/(d·a)和0.005;表型进展分别为0.066 kg/a、0.218 kg/a、3.388 g/天/a和0.092。综上,本研究可对天目多胎羊当前育种方案进行优化调整,进一步稳定其优良遗传性能,提高育种效率,节约饲养成本,为天目多胎羊的科学早期选育、提高生长性能和群体遗传稳定性提供理论依据。

In order to further improve the growth performance and breeding efficiency of Tianmu multiparous sheep,18534 pre-weaning weight data of Tianmu multiparous sheep from 2013 to 2022 were collected.The non-genetic factors affecting the lamb body weight traits of Tianmu multiparous sheep was analyzed.The genetic parameters and breeding values were estimated and their genetic trends and phenotypic trends was analyzed.The results showed that:1)Sex,birth year and birth season had extremely significant effect on the lamb body weight traits of Tianmu multiparous sheep(P<0.01).Brith type had significant effects on the preweaning Kleber ratio,and had extremely significant effects on other traits.2)Birth weight was a trait with medium heritability,with a direct heritability of 0.18±0.03,and a materal heritability of 0.13±0.02.Weaning weight(WWT),average daily gain before weaning(ADG)and pre-weaning Kleber ratio(KR)were low heritability traits,which the direct heritabilities were 0.06±0.02,0.06±0.02 and 0.02±0.01,the maternal heritabilities were 0.07±0.01,0.07±0.01and 0.09±0.01,respectively.3)Except for the negative genetic correlation and phenotypic correlation between BWT and KR,the other traits were positive genetic correlation and phenotypic correlation.4)The average breeding value of BWT showed a downward trend as a whole,and the average phenotypic value showed a trend of increasing first and then decreasing.The average breeding value and average phenotypic value of WWT decreased first and then increased.The average breeding value of ADG and the KR decreased first,then increased,then decreased and finally increased,and the average phenotypic value decreased first and then increased.5)The genetic gains of BWT,WWT,ADG and KR were−0.013 kg/a,−0.005 kg/a,−0.001 g/day/a and 0.005,respectively.The phenotypic gains were 0.066 kg/a,0.218 kg/a,3.388 g(/d·a)and 0.092,respectively.In summary,this study can optimize and adjust the current breeding program of Tianmu multiparous sheep,further stabilize its excellent genetic performance,improve breeding efficiency,save feeding costs,and provide a theoretical basis for the scientific early breeding,improvement of growth performance and population genetic stability of Tianmu multiparous sheep.