Williams A R, Franke D E, Saxton A M
Dept. of Anim. Sci., Louisiana State University Agricultural Center, Baton Rouge 70803.
J Anim Sci. 1991 Feb;69(2):531-42. doi: 10.2527/1991.692531x.
Reproductive data were collected on 4,595 cow exposures and subsequent calvings over four generations in a rotational crossbreeding study involving Angus, Brahman, Charolais and Hereford breeds. Direct and maternal additive (Ig and Mg) and nonadditive (Ih and Mh) genetic effects were estimated for calving rate, calf survival, weaning rate, calving assistance and calf birth date. Genetic effects were estimated by regressing individual animal response on the proportion of genes from breed of origin and gene combinations expected for the four breeds in offspring and in dams. Breed direct and maternal additive and nonadditive genetic effects were expressed as a deviation from the least squares mean. Brahman Ig effects decreased calving and weaning rate (-9.5 +/- 4.0 and -11.8 +/- 4.4%) but Mh effects for weaning rate that included Brahman were positive, ranging from 16.5 +/- 6.7% for Angus-Brahman to 27.8 +/- 6.9% for Brahman-Hereford. The Brahman Ig effect delayed calf birth date (9.8 +/- 2.1 d; P less than .01), whereas Angus and Hereford Ig effects influenced earlier calf birth dates (-4.3 +/- 1.9 and -4.1 +/- 1.9 d; P less than .05). Brahman combination Mh effects also influenced earlier calf birth dates (P less than .01). The Charolais Ig effect for calving assistance was positive (4.3 +/- 1.9%; P less than .05), whereas Angus-Brahman and Brahman-Charolais Mh effects for calving assistance were negative (-6.5 +/- 3.2 and -7.0 +/- 3.2%; P less than .05) and more desirable. Predicted reproductive traits for rotational mating systems were intermediate between predicted reproductive traits for two- and three-breed terminal crosses. Predicted calving and weaning rates were maximized when Brahaman first-cross and Charolais-Hereford cows were used in three-breed cross mating systems.
在一项涉及安格斯、婆罗门、夏洛莱和赫里福德品种的轮回杂交研究中，收集了四代中4595头母牛配种及随后产犊的繁殖数据。对产犊率、犊牛存活率、断奶率、产犊辅助和犊牛出生日期估计了直接和母体加性（Ig和Mg）以及非加性（Ih和Mh）遗传效应。通过将个体动物反应对后代和母畜中来自起源品种的基因比例以及四个品种预期的基因组合进行回归来估计遗传效应。品种直接和母体加性及非加性遗传效应表示为与最小二乘均值的偏差。婆罗门Ig效应降低了产犊率和断奶率（-9.5±4.0和-11.8±4.4%），但包含婆罗门的断奶率Mh效应为正，从安格斯-婆罗门的16.5±6.7%到婆罗门-赫里福德的27.8±6.9%不等。婆罗门Ig效应使犊牛出生日期延迟（9.8±2.1天；P＜0.01），而安格斯和赫里福德Ig效应影响犊牛出生日期提前（-4.3±1.9和-4.1±1.9天；P＜0.05）。婆罗门组合Mh效应也影响犊牛出生日期提前（P＜0.01）。夏洛莱Ig效应在产犊辅助方面为正（4.3±1.9%；P＜0.05），而安格斯-婆罗门和婆罗门-夏洛莱Mh效应在产犊辅助方面为负（-6.5±3.2和-7.0±3.2%；P＜0.05）且更有利。轮回交配系统的预测繁殖性状介于两品种和三品种终端杂交的预测繁殖性状之间。当在三品种杂交交配系统中使用婆罗门一代杂交母牛和夏洛莱-赫里福德母牛时，预测的产犊率和断奶率最高。
