Setshwaelo L L, Cundiff L V, Dickerson G E
U.S. Department of Agriculture, Clay Center, NE 68933.
J Anim Sci. 1990 Jun;68(6):1577-87. doi: 10.2527/1990.6861577x.
Effects of seven breeds of cow's sire and 12 breeds of cow's maternal grandsire on preweaning performance of crossbred cows and their calves were examined in data from two experiments conducted at the Roman L. Hruska U.S. Mean Animal Research Center. Data included 1,836 records over three to five parities for 516 cows by 143 sires and by 307 maternal grandsires. The statistical model fitted effects of calf sex, parity, cow birth-breeding year or cow-calf birth year, the breed effects and their interactions. Deviations of breed of sire or equivalent grandsire effects on each trait from the mean for Hereford x Angus cows ranged from -1.6 to 5.5 kg (P less than .001) for calf birth weights, -15 to 1% (P less than .001) for calving difficulty, nonsignificant for preweaning calf mortality and -2 to 27 kg (P less than .001) for calf weaning weight. Deviations were nonsignificant for conception rate and calves weaned per cow exposed to breeding, but -2 to 40 kg (P less than .001) for calf weight weaned per cow exposed for breeding, -7 to 78 kg (P less than .001) for cow weight and -20 to 2% (P less than .001) for body condition score. The advantages of Holstein and Brahman cross over Hereford x Angus cows of 23 and 13% in weight of calf weaned/cow-breeding exposure must be compared with the expected greater feed requirements from 7 or 8% heavier cows and at least 50% higher milk production, which emphasizes the need to include input measures and costs in breed evaluation schemes.
在美国罗马L.赫鲁斯卡家畜研究中心进行的两项实验数据中，研究了7个品种的公牛和12个品种的母牛外祖父对杂交母牛及其犊牛断奶前性能的影响。数据包括516头母牛与143头公牛以及307头母牛外祖父的三到五胎的1836条记录。统计模型拟合了犊牛性别、胎次、母牛出生繁殖年份或母牛-犊牛出生年份、品种效应及其相互作用。父本品种或等效外祖父品种对每个性状的影响与赫里福德×安格斯母牛的平均值相比，犊牛出生体重的偏差范围为-1.6至5.5千克（P小于0.001），产犊难度为-15至1%（P小于0.001），断奶前犊牛死亡率无显著差异，犊牛断奶体重为-2至27千克（P小于0.001）。受孕率和每头参与配种母牛的断奶犊牛数的偏差不显著，但每头参与配种母牛的断奶犊牛体重偏差为-2至40千克（P小于0.001），母牛体重偏差为-7至78千克（P小于0.001），体况评分偏差为-20至2%（P小于0.001）。荷斯坦和婆罗门杂交种相对于赫里福德×安格斯母牛在每头参与配种母牛的断奶犊牛体重方面有23%和13%的优势，但必须与预期的更高饲料需求相比较，因为母牛体重增加7%或8%，产奶量至少高出50%，这强调了在品种评估方案中纳入投入措施和成本的必要性。
