Gregory K E, Dearborn D D, Cundiff L V, Koch R M
Roman L. Hruska U.S. Meat Anim. Res. Center, U.S. Department of Agriculture, Clay Center, NE 68933.
J Anim Sci. 1987 Nov;65(5):1180-94. doi: 10.2527/jas1987.6551180x.
Crossbred steer and heifer progeny from 5-, 6- and 7-yr-old dams produced in a four-breed diallel crossing experiment involving the Brown Swiss, Red Poll, Hereford and Angus maternal grandsires and maternal granddams were evaluated for postweaning growth and carcass traits to estimate breed mean maternal heterosis, maternal heterosis for specific breed cross females, average maternal heterosis for all crosses, breed grandmaternal effects and net breed effects in crosses. All progeny evaluated were born in 1979 and 1980 and were sired by 7/8 or 15/16 Simmental bulls. Average maternal heterosis was significant for 200-d weight in heifers but not in steers and was not significant for final weight (444-d) in either heifers or steers. The effects of maternal heterosis on postweaning growth were not important. Differences among breeds in mean maternal heterosis values were small for growth-related traits. Breeds did not differ (P greater than .05) in grandmaternal effects for growth-related traits; Brown Swiss tended to be highest, Red Poll lowest, with Hereford and Angus intermediate. Differences in net breed effects in crosses favored Brown Swiss over the three other breeds and were generally significant for growth traits. Average maternal heterosis, though generally positive, was not significant for carcass traits on either an age-constant or weight-constant basis. Differences among breeds were small in grandmaternal effects, specific heterosis and net effects in crosses for carcass traits associated with both weight or composition; generally the Brown Swiss breed was favored on carcass traits associated with weight in the age-constant analysis and generally had a higher lean-to-fat ratio than the three other breeds in both the age-constant and weight-constant analyses.
在一项四品种双列杂交试验中，使用了瑞士褐牛、红白花牛、赫里福德牛和安格斯牛作为母系祖父母，培育出了5岁、6岁和7岁母本的杂交阉公牛和小母牛后代。这些后代由7/8或15/16西门塔尔公牛配种。对断奶后生长和胴体性状进行评估，以估计品种平均母本杂种优势、特定品种杂交母本的母本杂种优势、所有杂交组合的平均母本杂种优势、品种祖母效应以及杂交组合中的净品种效应。所有评估的后代均出生于1979年和1980年。小母牛200日龄体重的平均母本杂种优势显著，但阉公牛不显著；小母牛和阉公牛的最终体重（444日龄）均不显著。母本杂种优势对断奶后生长的影响并不重要。与生长相关性状的平均母本杂种优势值在品种间差异较小。在与生长相关性状的祖母效应方面，各品种间差异不显著（P大于0.05）；瑞士褐牛的效应往往最高，红白花牛最低，赫里福德牛和安格斯牛居中。杂交组合中净品种效应的差异使瑞士褐牛优于其他三个品种，且对生长性状通常具有显著意义。平均母本杂种优势虽然总体呈正向，但在年龄恒定或体重恒定基础上对胴体性状均不显著。在与体重或组成相关的胴体性状的祖母效应、特定杂种优势和杂交组合净效应方面，品种间差异较小；在年龄恒定分析中，瑞士褐牛在与体重相关的胴体性状上通常占优，在年龄恒定和体重恒定分析中，其瘦肉与脂肪比率通常高于其他三个品种。
