Browsing by Subject "Nutzbare Rohprotein"

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The effects of rumen nitrogen balance on nutrient digestion, protein metabolism, and performance of dairy cows as influenced by diet composition
(2021) Kand, Deepashree Dilip; Dickhöfer, Uta
Feeding excess dietary crude protein (CP) beyond the requirements of dairy cattle and microbes in the rumen increases production costs for farmers, excretion of nitrogen (N) to the environment, and has negative effects on the cows’ health and reproductive performance. Researchers have been interested in exploring the effects that diets with negative rumen nitrogen balance (RNB) may have on the dairy cattle and their rumen function. Results so far have been inconsistent may be due to the performance level of the animal with high-yielding dairy cows being more sensitive than low performing ones. Moreover, it may be supposed that variable responses to negative RNB in different studies may at least partly be related to varying ingredient composition and the type of main carbohydrate or N sources in the animals’ diets. The overall objective of the thesis was to generate a comprehensive understanding on the effects of interactions between the RNB levels and carbohydrate and N sources in cattle diets on rumen fermentation, the efficiency of microbial CP synthesis, and on N use efficiency in vitro and in vivo. The results of the present thesis indicate that the effects of negative RNB levels may vary with dietary composition in dairy cows. Therefore, outlining a single minimum RNB balance threshold for dairy cattle diets may not be appropriate when optimizing N utilization in dairy cows, because several animal and dietary factors modify the requirements of rumen microbes.