Van Vleck L D, Hanford K J, Snowder G D
ARS, USDA, U.S. Meat Animal Research Center, Lincoln 68583-0908, USA.
J Anim Sci. 2005 Mar;83(3):552-6. doi: 10.2527/2005.833552x.
Analyses of birth and weaning weights, fleece weights of ewes, and number born per litter of Polypay sheep collected at the U.S. Sheep Experimental Station from 1978 through 1998, confirmed previous analyses of three other dual-purpose breeds that cytoplasmic effects do not contribute to variation in these four traits. In general, estimates of genetic parameters that would be needed for national genetic evaluation were similar to previous estimates for Columbia, Rambouillet, and Targhee sheep, although estimates of direct heritability for Polypay were somewhat less for birth weight, slightly greater for weaning weight, significantly greater for fleece weight, and the same for number born as for those three breeds. For birth weight only, evidence was found for important dam x year or dam x number born interactions, which are essentially litter effects, as was found for the other dual-purpose breeds. There were 11,896, 11,104, 7,748, and 7,831 records for birth and weaning weights, fleece weight, and number born per litter, with 255 to 316 sires of animals with records. There were 260 and 261 cytoplasmic lines for fleece weight and number born, and 861 and 882 for weaning and birth weights.
对1978年至1998年在美国绵羊实验站收集的波利佩羊的出生体重、断奶体重、母羊羊毛重量和每窝产羔数进行的分析，证实了之前对其他三个兼用品种的分析结果，即细胞质效应不会导致这四个性状的变异。总体而言，国家遗传评估所需的遗传参数估计值与之前对哥伦比亚羊、兰布耶羊和塔吉羊的估计值相似，不过波利佩羊出生体重的直接遗传力估计值略低，断奶体重的估计值略高，羊毛重量的估计值显著更高，每窝产羔数的估计值与那三个品种相同。仅就出生体重而言，发现了重要的母羊×年份或母羊×产羔数的互作效应，这本质上就是窝效应，其他兼用品种也有这种情况。出生体重、断奶体重、羊毛重量和每窝产羔数的记录分别有11,896条、11,104条、7,748条和7,831条，有记录的动物的父本有255至316个。羊毛重量和每窝产羔数的细胞质系分别有260个和261个，断奶体重和出生体重的细胞质系分别有861个和882个。
