Bunge R, Thomas D L, Stookey J M
University of Illinois, Urbana 61801.
J Anim Sci. 1990 Aug;68(8):2253-62. doi: 10.2527/1990.6882253x.
Objectives of this study were to estimate the magnitude of the effects of various factors associated with ewes and their ram lamb mates on fertility, prolificacy, lamb survival, lamb weaning weight and ewe productivity and to estimate the heritability and repeatability of each trait. Records from 731 ewe-years, 75 ram lamb sires and 616 lambs born from the University of Illinois Rambouillet flock were used. Ewes mated to single-born ram lambs had higher fertility rates (P less than .01), gave birth to lambs with higher survival rates (P less than .01), weaned lighter (P less than .05) individual lambs but weaned more weight of lamb per ewe exposed (P less than .01) than ewes mated to multiple-born ram lambs. Ram lamb breeding weight, ram lamb scrotal circumference, ewe breeding weight and ewe age had relatively large and positive effects on the composite trait of weight of lamb weaned per ewe exposed and significant effects on a number of the component traits. Heritability and repeatability estimates were, respectively, as follows: fertility, 3%, 3%; prolificacy, 34%, 19%; lamb survival, 15%, 8%; lamb weaning weight, 7%, 36%; and ewe productivity, 27%, 10%.
本研究的目的是评估与母羊及其所配公羊羔羊相关的各种因素对繁殖力、产仔数、羔羊存活率、羔羊断奶体重和母羊生产力的影响程度，并估计每个性状的遗传力和重复性。使用了伊利诺伊大学兰布耶羊群的731个母羊年度记录、75只公羊羔羊父本记录以及616只出生羔羊的记录。与单胎出生公羊羔羊交配的母羊繁殖率更高（P小于0.01），所产羔羊存活率更高（P小于0.01），单只羔羊断奶时体重较轻（P小于0.05），但每只受配母羊的断奶羔羊总重更高（P小于0.01），而与多胎出生公羊羔羊交配的母羊情况则相反。公羊羔羊的配种体重、阴囊周长、母羊的配种体重和年龄对每只受配母羊的断奶羔羊体重这一综合性状有相对较大的正向影响，对一些组成性状也有显著影响。遗传力和重复性估计值分别如下：繁殖力，3%，3%；产仔数，34%，19%；羔羊存活率，15%，8%；羔羊断奶体重，7%，36%；母羊生产力，27%，10%。
