Department of Animal and Poultry Sciences, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
J Anim Sci. 2009 Nov;87(11):3506-14. doi: 10.2527/jas.2008-1622. Epub 2009 Jul 31.
Data from the Montana State University Targhee flock were used to estimate genetic and environmental relationships between lamb BW and adult ewe BW, condition score, and prolificacy. The flock was managed under commercial western range conditions typical of the area. Data included records from 12,154 lambs born to 2,930 dams and 200 rams between 1960 and 2005. Lamb traits included BW at birth and approximately 45 d, 120 d (weaning), 12 mo, and 18 mo of age and fleece characteristics at 12 mo of age. Adult traits included ewe litter size; BW and BCS at weaning, in late gestation, and in early lactation; and adult fleece measurements. Multiplicative factors were used to adjust (pre)weaning lamb BW for effects of age of dam, type of birth and rearing, and lamb sex and to adjust adult litter sizes for effects of ewe age. An animal model was used to estimate genetic relationships. Models for lamb traits included fixed effects of year of birth and, for postweaning data, lamb sex and random additive genetic effects and, for (pre)weaning BW, additive genetic maternal and permanent environmental maternal effects. Models for adult traits included fixed effects of year of birth, year of record, and, when appropriate, numbers of lambs born or born and reared and random additive genetic and animal permanent environmental effects. Heritability estimates for lamb birth weight, 45-d BW, weaning weight, yearling weight, 18-mo BW, fleece weight, staple length, and spinning count were 0.19, 0.07, 0.12, 0.32, 0.38, 0.32, 0.31, and 0.25, respectively. Maternal heritabilities for lamb birth, 45-d, and weaning weights were 0.15, 0.09, and 0.08, respectively. Heritability estimates for adult traits were 0.12 for litter size, averaged 0.43 for BW and 0.13 for body condition, and were 0.44, 0.37, and 0.25 for adult fleece weight, staple length, and spinning count, respectively. Correlations between genetic effects on adult BW and direct and maternal genetic effects on lamb BW ranged from 0.21 to 0.96 (P < 0.05) and 0.29 to 0.53 (P < 0.05), respectively, with residual correlations ranging from 0.05 to 0.95. Correlations of lamb traits with adult body condition and number of lambs born were generally not different from zero; genetic and residual correlations ranged from -0.52 to 0.69 and -0.39 to 0.31, respectively.
利用蒙大拿州立大学塔格hee 羊群的数据来估计羔羊 BW 和成年母羊 BW、体况评分和繁殖力之间的遗传和环境关系。该羊群在典型的西部牧场条件下进行商业管理。数据包括 1960 年至 2005 年间 2930 只母羊和 200 只公羊所生的 12154 只羔羊的记录。羔羊性状包括出生时和大约 45、120（断奶）、12 月龄和 18 月龄时的 BW 和羊毛特征，以及 12 月龄时的羊毛特征。成年性状包括母羊产羔数；断奶、妊娠后期和泌乳早期时的 BW 和 BCS；以及成年羊毛测量值。使用乘法因子来调整母羊年龄、产羔和育羔类型以及羔羊性别对（预）断奶羔羊 BW 的影响，并调整成年产羔数以适应母羊年龄的影响。使用动物模型估计遗传关系。羔羊性状模型包括出生年份的固定效应，以及断奶后数据的羔羊性别和随机加性遗传效应，以及（预）断奶 BW 的加性遗传母性和永久性环境母性效应。成年性状模型包括出生年份、记录年份以及适当的出生和育羔羔羊数量的固定效应，以及随机加性遗传和动物永久性环境效应。羔羊初生重、45 日龄 BW、断奶重、1 岁重、18 月龄 BW、羊毛重、纤维长度和纺线数的遗传力估计值分别为 0.19、0.07、0.12、0.32、0.38、0.32、0.31 和 0.25。羔羊初生、45 日龄和断奶时的母体遗传力分别为 0.15、0.09 和 0.08。成年性状的遗传力估计值为产羔数 0.12，BW 平均 0.43，体况 0.13，成年羊毛重、纤维长度和纺线数分别为 0.44、0.37 和 0.25。成年 BW 的直接和母体遗传效应与羔羊 BW 的遗传效应之间的相关性从 0.21 到 0.96（P<0.05）和 0.29 到 0.53（P<0.05）不等，残差相关性从 0.05 到 0.95 不等。羔羊性状与成年体况和产羔数的相关性通常与零无差异；遗传和残差相关性分别为-0.52 至 0.69 和-0.39 至 0.31。
