EVALUATION OF STRATEGIES FOR CROSSBREEDING OF DAIRY-CATTLE IN BRAZIL
EVALUATION OF STRATEGIES FOR CROSSBREEDING OF DAIRY-CATTLE IN BRAZIL
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DOI：
10.3168/jds.s0022-0302(90)78869-8
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发表时间：
1990-07-01
影响因子：
3.5
通讯作者：
BARBOSA, RT
中科院分区：
文献类型：
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作者：
MADALENA, FE;TEODORO, RL;BARBOSA, RT
为了比较育种策略，计算了 376 头红牛和白牛荷斯坦-弗里斯兰奶牛的经济表现。 Guzera 杂交群体（1/4 至 .gtoreq. 31/32 欧洲等级），基于其累积乳制品产量（60 个农场的 914 个泌乳期）以及对 87 头非新鲜小母牛的扑杀或死亡观察。性能是根据基于加性显性和间交配效应的遗传模型预测的：利用F1雌性、升级为荷斯坦-弗里斯兰、新的合成品种、纵横交配和改良杂交（荷斯坦-弗里斯兰公牛为两代，瘤牛公牛为一代）。在管理较好的农场中，这些策略的牛群生活每天利润分别相当于 1.82、1.36、-.33、.75 和 1.36 公斤牛奶，而管理水平较低的农场的相应当量为 4.64、-.95、1.37、2.72 和 2.23 公斤。在低管理水平下，群体之间的扑杀率和死亡率差异相当大，影响牛群寿命和小母牛成本，并降低欧洲高等级的利润。选择将适当的动物遗传资源与畜牧实践相匹配的育种策略可能会产生重要的经济收益。连续的 F1 小母牛替代计划可能具有良好的经济基础，特别是对于低管理水平的农场。对于这些农场来说，杂交是第二好的选择。在管理较好的农场，改进的交叉和升级在当前价格下具有相似的性能，但前者在脂肪和蛋白质定价较高的情况下会更有利可图。
To compared breeding strategies, economic performance was calculated for 376 cows of six red and white Holstein-Friesian .times. Guzera crossbred groups (1/4 to .gtoreq. 31/32 European grades), based on their accumulated dairy production (914 lactations of 60 farms) and on culling or death observations of 87 nonfreshening heifers. Performance was predicted from a genetic model based on additive-dominance and inter se mating effects for the following: utilization of F1 females, upgrading to Holstein-Friesian, new synthetic breed, crisscrossing, and modified crosscrossing (of Holstein-Friesian sires for two generations and zebu sires for one generation). On the better-managed farms, profit per day of herd life for those strategies, was equivalent to, respectively, 1.82, 1.36, -.33, .75, and 1.36 kg of milk, whereas corresponding equivalence on low management level farms was 4.64, -.95, 1.37, 2.72, and 2.23 kg. Differences between groups in culling and mortality rates were considerable in the low management level, influencing herd life and heifer cost and reducing profit of high European grades. Important economic gains may accrue from choice of a breeding strategy to match the appropriate animal genetic resources to husbandry practices. Continuous F1 heifer replacement programs may have sound economic basis, particularly for low management level farms. Crosscrossing was the second best alternative for those farms. On the better-managed farms, modified crisscrossing and upgrading had similar performance under present prices, but the former would be more profitable under higher pricing of fat and protein.