Chase C C, Olson T A, Hammond A C, Menchaca M A, West R L, Johnson D D, Butts W T
Agricultural Research Service, USDA, Brooksville, FL 34601-4672, USA.
J Anim Sci. 1998 Dec;76(12):2967-75. doi: 10.2527/1998.76122967x.
We conducted a multiyear study in two phases to determine preweaning performance traits of Senepol (S x S), Hereford (H x H), and reciprocal (S x H and H x S) F1 crossbred calves and feedlot performance and carcass characteristics of steers. In Phase I, from 1985 to 1989, data from S x S (n = 194), H x H (n = 383), and S x H (n = 120) calves were used. Numbers of S x S cows were increased during Phase I so that data from H x S (n = 74) calves could be included in Phase II (1990 to 1992) in addition to S x S (n = 118), H x H (n = 130), and S x H (n = 56) calves. Also during Phase II, feedlot performance and carcass characteristics were determined for S x S (n = 30), H x H (n = 26), H x S (n = 36), and S x H (n = 26) steers. In Phase I, S x S calves had heavier (P < .01) birth weights and heavier (P < .01) 205-d adjusted weaning weights than H x H calves. Birth weights of S x H calves were heavier (P < .01) than the mean of the purebred calves, but 205-d adjusted weaning weights did not differ (P > .10). In phase II, direct heterosis was 3.5% for birth weight (P < .05) and 5.1% for 205-d adjusted weaning weight (P < .01). Senepol maternal breed effects were 1.9 kg for birth weight (P < .10) and 37.9 kg for 205-d adjusted weaning weight (P < .01). Levels of direct heterosis, Senepol maternal breed effects, and Hereford direct breed effects were significant for most feedlot performance traits of steer calves that were fed to a common end point. Breeds did not differ (P > .10) for USDA yield and quality grades, and direct heterosis was not significant for Warner-Bratzler shear force. These results demonstrate significant levels of heterosis in preweaning performance between S x S and H x H calves and in feedlot performance of steers. Levels of heterosis were smaller and nonsignificant for most carcass traits including meat tenderness, which did not differ between S x S and H x H steers in this study.
我们分两个阶段进行了一项多年研究，以确定塞内波尔（S×S）、赫里福德（H×H）以及正反交（S×H和H×S）F1杂交犊牛的断奶前生产性能性状，以及阉牛的育肥性能和胴体特征。在第一阶段（1985年至1989年），使用了S×S（n = 194）、H×H（n = 383）和S×H（n = 120）犊牛的数据。在第一阶段增加了S×S母牛的数量，以便在第二阶段（1990年至1992年）除了S×S（n = 118）、H×H（n = 130）和S×H（n = 56）犊牛的数据外，还能纳入H×S（n = 74）犊牛的数据。同样在第二阶段，测定了S×S（n = 30）、H×H（n = 26）、H×S（n = 36）和S×H（n = 26）阉牛的育肥性能和胴体特征。在第一阶段，S×S犊牛的出生体重更重（P <.01），205日龄校正断奶体重也更重（P <.01），高于H×H犊牛。S×H犊牛的出生体重比纯种犊牛的平均值更重（P <.01），但205日龄校正断奶体重没有差异（P >.10）。在第二阶段，出生体重的直接杂种优势为3.5%（P <.05），205日龄校正断奶体重的直接杂种优势为5.1%（P <.01）。塞内波尔母本品种效应在出生体重方面为1.9千克（P <.10），在205日龄校正断奶体重方面为37.9千克（P <.01）。对于育肥至相同终点的阉牛犊牛的大多数育肥性能性状，直接杂种优势水平、塞内波尔母本品种效应以及赫里福德直接品种效应均显著。不同品种在USDA产量和质量等级方面没有差异（P >.10），并且沃纳-布拉茨勒剪切力的直接杂种优势不显著。这些结果表明，S×S和H×H犊牛在断奶前生产性能以及阉牛育肥性能方面存在显著的杂种优势水平。对于大多数胴体性状，包括肉的嫩度，杂种优势水平较小且不显著，在本研究中S×S和H×H阉牛之间没有差异。
