Smith B A, Brinks J S, Richardson G V
Dept. of Anim. Sci. Colorado State University, Fort Collins 80523.
J Anim Sci. 1989 Nov;67(11):2886-91.
Growth and reproductive data were obtained on 779 beef heifers at the San Juan Basin Research Center, Hesperus, Co. Genetic parameters were estimated for age of puberty (AOP), age of first calving (AOC), julian day of first calving (DOC), julian day of second calving (DOSC), birth weight, weaning weight, yearling weight, and average daily gain from weaning to yearling and to cycling weights. The least squares model included birth year, age of dam and breed as fixed effects, sire/breed as a random variable, and day of birth and percent inbreeding as covariates. Day of birth was not included in the analyses of AOC, DOC or DOSC. Paternal half-sib estimates of heritability were: AOP, .10 +/- .17; AOC, .01 +/- .12; DOC, .09 +/- .13 and DOSC, .36 +/- .18. Genetic and phenotypic correlations were generally favorable, but genetic correlations were variable with large standard errors. Inbreeding had a detrimental effect on reproductive traits, and a seasonal effect was present for AOP.
在科罗拉多州赫斯珀勒斯的圣胡安盆地研究中心，获取了779头肉用小母牛的生长和繁殖数据。对初情期年龄（AOP）、首次产犊年龄（AOC）、首次产犊的儒略日（DOC）、第二次产犊的儒略日（DOSC）、出生体重、断奶体重、周岁体重以及从断奶到周岁和到发情体重的平均日增重等遗传参数进行了估计。最小二乘模型将出生年份、母牛年龄和品种作为固定效应，父系/品种作为随机变量，出生日和近亲繁殖百分比作为协变量。出生日未纳入AOC、DOC或DOSC的分析中。父系半同胞遗传力估计值为：AOP，0.10±0.17；AOC，0.01±0.12；DOC，0.09±0.13；DOSC，0.36±0.18。遗传和表型相关性总体良好，但遗传相关性变化较大且标准误差较大。近亲繁殖对繁殖性状有不利影响，AOP存在季节性效应。
