Yilmaz A, Davis M E, Simmen R C M
Department of Animal Sciences, The Ohio State University, 221 Plumb Hall, 2027 Coffey Road, Columbus, OH 43210, USA.
Theriogenology. 2006 Apr 1;65(6):1180-90. doi: 10.1016/j.theriogenology.2005.06.018. Epub 2005 Sep 6.
Insulin-like growth factor-I (IGF-I) is an anabolic polypeptide involved in reproductive performance in several species. The objectives of this study were to determine relationships of pregnancy rate, and age of heifers at puberty and at first calving with serum IGF-I concentration in Angus beef cattle. Data were obtained from an ongoing divergent selection experiment for IGF-I concentration involving purebred Angus cows. The IGF-I concentrations measured at Days 28, 42, and 56 of the 140-day postweaning test are abbreviated as IGF28, IGF42, and IGF56, respectively. Pregnancy rate did not differ between high and low IGF-I line females (P=0.95; n=2618), but high line heifers tended to be 4.02+/-2.18 days younger (P=0.07; n=281) at first calving. Residual correlations of age of heifers at first calving (AFC) with IGF-I measurements were not significant. The linear and quadratic terms for regression of AFC on IGF-I concentrations were also non-significant. Contrast analysis showed no difference in age at puberty between the high and low IGF-I line heifers (5.3+/-6.4 days earlier in the high line; P=0.43; n=51). Residual correlations of age of heifers at puberty with IGF28, IGF42, IGF56, and mean IGF-I were -0.30 (P=0.03), -0. 22 (P=0.12), -0.35 (P=0.01), and -0.34 (P=0.01), respectively. The observed relationships between female reproductive traits and IGF-I concentration in Angus beef cattle suggest complex and multiple roles for IGF-I in reproduction.
胰岛素样生长因子-I（IGF-I）是一种合成代谢多肽，参与多种物种的繁殖性能。本研究的目的是确定安格斯肉牛的妊娠率、青春期和首次产犊时小母牛的年龄与血清IGF-I浓度之间的关系。数据来自一项正在进行的关于IGF-I浓度的纯种安格斯母牛的定向选择实验。在断奶后140天试验的第28、42和56天测量的IGF-I浓度分别简称为IGF28、IGF42和IGF56。高IGF-I系和低IGF-I系雌性的妊娠率没有差异（P=0.95；n=2618），但高系小母牛首次产犊时的年龄往往小4.02±2.18天（P=0.07；n=281）。首次产犊时小母牛的年龄（AFC）与IGF-I测量值的残差相关性不显著。AFC对IGF-I浓度的线性和二次回归项也不显著。对比分析表明，高IGF-I系和低IGF-I系小母牛的青春期年龄没有差异（高系早5.3±6.4天；P=0.43；n=51）。小母牛青春期年龄与IGF28、IGF42、IGF56和平均IGF-I的残差相关性分别为-0.30（P=0.03）、-0.22（P=0.12）、-0.35（P=0.01）和-0.34（P=0.01）。安格斯肉牛雌性繁殖性状与IGF-I浓度之间观察到的关系表明IGF-I在繁殖中具有复杂和多重作用。
