Williams A R, Franke D E, Saxton A M, Turner J W
Louisiana State University Agricultural Center, Baton Rouge 70803.
J Anim Sci. 1990 Jun;68(6):1536-46. doi: 10.2527/1990.6861536x.
Reproductive data were collected on 4,596 cow exposures in a rotational crossbreeding study that spanned four generations (1970 through 1988). Angus (A), Brahman (B), Charolais (C) and Hereford (H) breeds were included in three two-breed (A-B, C-B and H-B), three three-breed (A-B-C, A-B-H and C-H-B) and one four-breed (A-B-C-H) rotational mating system. Contemporary straightbreds were produced each generation. Reproductive traits of interest were calving rate, calf survival, weaning rate, calf birth date and calving assistance. Overall means and standard errors for calving rate, calf survival, weaning rate, calf birth date and calving assistance were 82.1 +/- .6%, 92.8 +/- .4%, 76.2 +/- .6%, 50.4 +/- .3 d and 4.2 +/- .3%, respectively. Rotational mating systems had similar calving and calf survival rates that were greater (P less than .01) than those of straightbreds. Three- and four-breed rotation systems had similar weaning rates (81.5 +/- 1.1 and 80.8 +/- 2.0%) that were higher than those for two-breed rotations (77.1 +/- 1.2%). Two- and three-breed rotation systems had fewer assisted births (3.5 +/- .6 and 2.2 +/- .6%) than straightbreds (5.5 +/- .6%) and the four-breed rotation (5.4 +/- 1.0%). Three-breed rotation calves were born earlier in the calving season (46.8 +/- .6 d; P less than .05) than straightbred, two-breed or four-breed rotation calves (51.8 +/- .6, 52.1 +/- .6 and 51.1 +/- 1.0 d). Hereford-Brahman two-breed rotation cows had higher (P less than .05) calving and weaning rates than A-B or C-B two-breed rotation cows (87 +/- .4 vs 81.9 +/- 1.9 and 81.5 +/- 1.8%; 81.7 +/- 2.0 vs 76.4 +/- 2.1 and 74.1 +/- 2.0%). All three-breed rotation combinations had similar calving, calf survival and weaning rates, assistance at calving and calf birth dates. Rotational combinations tended to be more superior (P less than .05) to weighted purebred means for calving, calf survival and weaning rates than for calf birth date and calving assistance.
在一项跨越四代（1970年至1988年）的轮回杂交研究中，收集了4596头母牛配种的繁殖数据。该研究涉及安格斯（A）、婆罗门（B）、夏洛来（C）和赫里福德（H）四个品种，采用了三种两品种（A-B、C-B和H-B）、三种三品种（A-B-C、A-B-H和C-H-B）和一种四品种（A-B-C-H）的轮回交配系统。每一代都培育了同期的纯种牛。所关注的繁殖性状包括产犊率、犊牛成活率、断奶率、犊牛出生日期和产犊辅助情况。产犊率、犊牛成活率、断奶率、犊牛出生日期和产犊辅助情况的总体均值和标准误分别为82.1±0.6%、92.8±0.4%、76.2±0.6%、50.4±0.3天和4.2±0.3%。轮回交配系统的产犊率和犊牛成活率相似，且高于纯种牛（P<0.01）。三品种和四品种轮回系统的断奶率相似（分别为81.5±1.1%和80.8±2.0%），高于两品种轮回系统（77.1±1.2%）。两品种和三品种轮回系统的助产率（分别为3.5±0.6%和2.2±0.6%）低于纯种牛（5.5±0.6%）和四品种轮回系统（5.4±1.0%）。三品种轮回系统的犊牛在产犊季节出生时间更早（46.8±0.6天；P<0.05），相比纯种、两品种或四品种轮回系统的犊牛（分别为51.8±0.6天、52.1±0.6天和51.1±1.0天）。赫里福德-婆罗门两品种轮回母牛的产犊率和断奶率高于A-B或C-B两品种轮回母牛（分别为87±0.4%对81.9±1.9%和81.5±1.8%；81.
