Marlowe T J, Notter D R, Brown R A, Tolley E A
J Anim Sci. 1984 Jul;59(1):11-22. doi: 10.2527/jas1984.59111x.
Over six calf crops, 524 exposures of Angus cows to three sire breeds resulted in 432 weaned calves for an 82.4% calf crop. Least-squares means for weaning rate by sire breed were 81.8, 80.5 and 83.9% for Angus, Charolais and Holsteins, respectively. Sire breed effect was not significant for calving rate, calf mortality or overall weaning rate, but was significant for all growth traits from birth to 18 mo. Angus-sired calves were smallest at birth, grew at a slower rate and were lightest in weight at all ages. Charolais-sired calves were heaviest at all weigh periods and Holstein-sired calves were intermediate. Holstein-sired calves scored significantly lower for both grade and condition than did Angus- and Charolais-sired calves. Charolais-sired calves had the highest grade. Calving rate tended to be influenced by the effect of cow (P less than .10) and sire breed X year (P less than .001). Calving rate was highest for 3-yr-old and for 6- to 10-yr-old cows and was also 1.5 percentage units higher for crossbred matings. Cow productivity (kg of calf weaned/cow exposed) is a combined measure of fertility, calf survival and weaning weight. Although sire breed did not significantly affect cow productivity (P less than .20), actual values favored cows producing crossbred calves by 14 and 9 kg for Charolais and Holstein crosses, respectively. Likewise, weight differences at 18 mo favored these crosses by 50 and 32 kg for heifers and 72 and 62 kg for steers. Among the two crossbred types, Charolais X Angus heifers were 28 kg heavier (P less than .05) than Holstein X Angus heifers at 18 mo but the 10 kg difference in steers was not significant. The fact that the large sire breeds produced calves with heavier weaning weights without demonstrating significant increases in overall productivity points out the importance of high weaning rates.
在六个犊牛繁殖周期中，524头安格斯母牛与三个父本品种进行配种，共产出432头断奶犊牛，犊牛繁殖率为82.4%。按父本品种计算的断奶率最小二乘均值，安格斯、夏洛莱和荷斯坦公牛分别为81.8%、80.5%和83.9%。父本品种对产犊率、犊牛死亡率或总体断奶率无显著影响，但对出生至18月龄的所有生长性状有显著影响。安格斯公牛所产犊牛出生时最小，生长速度较慢，各年龄段体重最轻。夏洛莱公牛所产犊牛在各体重阶段最重，荷斯坦公牛所产犊牛体重居中。荷斯坦公牛所产犊牛在等级和体况评分上显著低于安格斯和夏洛莱公牛所产犊牛。夏洛莱公牛所产犊牛等级最高。产犊率往往受母牛效应（P<0.10）和父本品种×年份效应（P<0.001）的影响。3岁母牛以及6至10岁母牛的产犊率最高，杂交配种的产犊率也高出1.5个百分点。母牛生产力（断奶犊牛体重/配种母牛体重，单位：千克）是繁殖力、犊牛存活率和断奶体重的综合指标。尽管父本品种对母牛生产力无显著影响（P<0.20），但实际数据显示，夏洛莱和荷斯坦杂交母牛所产犊牛体重分别比安格斯母牛所产犊牛重14千克和9千克。同样，18月龄时，杂交犊牛的体重差异，小母牛为50千克和32千克，公牛为72千克和62千克。在两种杂交类型中，18月龄时，夏洛莱×安格斯小母牛比荷斯坦×安格斯小母牛重28千克（P<0.05），但公牛10千克的体重差异不显著。大型父本品种所产犊牛断奶体重较重，但总体生产力未显著提高，这一事实凸显了高断奶率的重要性。
