本试验应用体外批次培养法，研究了不同精粗比（2：8与3：7）日粮甲烷产量的差异。
Based on in vitro batch incubation, different methane production of two diets with different forage:concentrte ratios(2:8 and 3:7) was compared.
本论文第二部分主要研究了四种不同精粗比典型日粮条件下泌乳奶牛瘤胃氮素代谢、小肠蛋白质的消化吸收及其对生产性能的影响。
The second part was mainly conducted to study the effects of four typical diets on rumen nitrogen metabolism, protein digestion and absorption in the small intestine, and dairy cow's milk performance.
角色和职责（在比OO更粗的级别上）
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