在过去的半个世纪中，世界畜牧业取得了长足发展。畜牧生产水平显著提高，畜产品产量大大增加，畜牧业在满足人类动物食品的需求方面作出了巨大贡献。然而，畜牧业仍然是低效产业。动物将饲料养分转化为畜产品的效率只有%#)*“$)，+$)*+#)的食入养分排入环境，对土壤、空气、水 In the past half century, the world’s livestock husbandry has made great strides. The level of livestock production has risen significantly, the output of livestock products has greatly increased, and the livestock husbandry has made a significant contribution to meeting the needs of human animal food products. However, livestock husbandry remains an inefficient industry. Animals feed nutrients into livestock products efficiency only% #) * ”$), + $) * + #) into the environment, on the soil, air, water