Michigan State University Extension, Michigan State University, Sandusky, MI 48471, USA.
Department of Animal Science, University of California Davis, Holtville, CA 92250, USA.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skac345.
The contribution of dairy steers to the U.S. fed beef supply has increased from 6.9% to 16.3% over the last two decades; in part, due to declining beef cow numbers and the increased use of sexed dairy semen to produce genetically superior replacement heifers from the best dairy cows. Raising dairy cattle for beef production offers unique opportunities and challenges when compared with feeding cattle from beef breeds. Dairy steers offer predictable and uniform finishing cattle performance (ADG, DMI, G:F) as a group and more desirable quality grades on average compared with their beef steer counterparts. However, dairy steers have lesser dressing percentages and yield 2%-12% less red meat compared with beef steers due to a greater ratio of bone to muscle, internal fat, organ size, and gastrointestinal tract weight. In addition, carcasses from dairy steers can present problems in the beef packing industry, with Holstein carcasses being longer and Jersey carcasses being lighter weight than carcasses from beef breeds. Beef × dairy crossbreeding strategies are being implemented on some dairy farms to increase the income generated from dairy bull calves, while beef × dairy crossbreeding strategies can also improve the G:F and red meat yield of beef produced from the U.S. dairy herd. This alternative model of beef production from the dairy herd is not without its challenges and has resulted in variable results thus far. Successful adoption of beef × dairy crossbreeding in the cattle industry will depend on the proper selection of beef sires that excel in calving ease, growth, muscling, and marbling traits to complement the dairy genetics involved in beef production.
在过去的二十年中,奶牛育肥牛在美国饲料牛肉供应中的占比从 6.9%增加到 16.3%;部分原因是牛肉母牛数量下降,以及越来越多地使用性控奶牛精液,从最好的奶牛中生产出遗传上更优秀的后备小母牛。与饲养肉牛品种相比,饲养奶牛生产牛肉具有独特的机遇和挑战。与肉牛育肥牛相比,奶牛育肥牛作为一个群体提供可预测且均匀的育肥牛性能(ADG、DMI、G:F),并且平均具有更理想的质量等级。然而,由于骨骼与肌肉的比例更大、内部脂肪、器官大小和胃肠道重量更大,奶牛育肥牛的出肉率和可食红肉产量比肉牛育肥牛低 2%-12%。此外,由于荷斯坦牛胴体较长,泽西牛胴体较轻,与肉牛品种的胴体相比,来自奶牛育肥牛的胴体在牛肉包装行业可能会出现问题。一些奶牛场正在实施肉牛与奶牛杂交策略,以增加来自奶牛公牛犊的收入,同时,肉牛与奶牛杂交策略还可以提高来自美国奶牛群的牛肉的 G:F 和可食红肉产量。这种来自奶牛群的牛肉生产的替代模式并非没有挑战,迄今为止,结果并不稳定。肉牛与奶牛杂交在牛业中的成功应用将取决于正确选择在产犊容易、生长、肌肉和大理石花纹性状方面表现出色的肉牛种公牛,以补充涉及牛肉生产的奶牛遗传基因。