Effects of rumen-degradable-protein to rumen-undegradable-protein ratio on nitrogen conversion of lactating dairy cows |
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| Authors: | C Wang S W Zhai J L Lai Y M Wu |
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| Institution: | Institute of Dairy Science, MOE Key Laboratory of Molecular Animal Nutrition , Zhejiang University , Hangzhou, P. R. China |
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| Abstract: | Abstract Fifteen multiparous dairy cows were used in a five replicated 3×3 Latin square design to study the effects of ratio of rumendegradable-protein (RDP) and rumen-undegradable-protein (RUP) on nitrogen (N) conversion in Chinese Holstein dairy cows. Three diets were formulated isonitrogenously with varying ratio of RDP/RUP. High ratio of RDP/RUP resulted in high urinary N excretion and total N excretion, but no significant dietary effects were observed on milk yield, milk composition, and nitrogen excretion in faeces. Different protein degradability changed the partitioning of the N excretion between urine and faeces. Results indicated that reduction in ratio of RDP/RUP could improve the efficiency of N utilization in lactating dairy cows by reduced N excretion in urine and faeces without impairing milk production. |
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| Keywords: | Dairy cows nitrogen excretion protein degradability rumen-degradable-protein |
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