湖羊出生类型与产活羔数表型及遗传参数估计

收集了26只湖羊种公羊115个女儿共计458窝产羔记录。统计分析表明，湖羊母羊胎产活羔数为1－5羔的比例分别为21．18％、49．78％、25．76％、3．06％和0．22％；公羊对母羊出生类型和产活羔数具有显著影响，胎次对母羊出生类型和产活羔数没有显著影响；母羊出生类型对其产活羔数没有显著影响；湖羊母羊出生类型与产活羔数的遗传力分别为0．251和0．097，它们之间的遗传、表型和环境相关分别为0．241、0．008和0．181，它们之间的协遗传力为0．038。这些参数表明：母羊出生类型与产活羔数是遗传联系不紧密的两个不同性状；根据母羊出生类型来早期选择产活羔数是无效的。

Estimation of Phenotypic and Genetic Parameters for Birth Type

A total number of 458 litter records from 115 daughters of 26 stock rams collected at the Yuhang Hu Sheep Farm were analysed. The statistical analyses indicated that the proportion of 1 tO 5 lambs per litter was 21.18%, 49.78%, 25.76%, 3.06% and 0.22%, respectively. Rains significantly influenced birth type and number of lambs born alive in the ewes. Parity didn' t affect significantly birth type and number of lambs born alive. Birth type of the ewes did not significantly influenc their number of lambs born alive. The estimated heritability was 0.251 for birth type and 0.097 for number of lambs born alive. The genetic, phenotypic and environmental correlations between birth type and number of lambs born alive were 0.241, 0.008 and 0.181, respectively. The coheritability for birth type and number of lambs born alive was 0.038. These parameters indicated that birth type and number of lambs born alive were two different traits which were not closely correlated genetically. Early selection for number of lambs born alive based on ewe birth type was ineffective.