[Estimation of phenotypic and genetic parameters for birth type and number of lambs born alive in hu sheep].
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. Rams 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 influence 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.
Chu
M X
MX
Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100094, China. mxchu@263.net
Wang
X L
XL
D000818:Animals; D005260:Female; D008297:Male; D010641:Phenotype; D011247:Pregnancy; D012098:Reproduction; D012756:Sheep / Q000235:genetics* / Q000502:physiology