This study investigated the effect of adaptation to grazing in early spring on herbage intake, ruminal fermentation parameters, blood metabolite concentrations, and body weight change in dairy cows. The experiment was conducted on eight rumen‐cannulated non‐lactating cows in the early spring period. Four cows were adapted to grazing by stocking for 4 hr for 1 week (ADP group). The other cows were kept in a barn during the period (CON group). Then, both groups of cows were stocked together throughout a day on a 1 ha pasture for 3 weeks (experimental period). In the first week of the experimental period, compared to the CON group, the ADP group had a higher herbage intake, ruminal NH₃‐N and total VFA concentration, and blood urea concentration, but the NEFA concentration was lower in the ADP group (p < .01). During the subsequent weeks, there were little differences in ruminal fermentation parameters and blood metabolites. Cows in the ADP group maintained their body weight, but cows in the CON group lost 60 kg of body weight in the first week of the experimental period.

中文翻译：

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放牧适应对早春放牧后奶牛采食量、瘤胃发酵、血液代谢物和体重变化的影响

本研究调查了适应早春放牧对奶牛采食量、瘤胃发酵参数、血液代谢物浓度和体重变化的影响。该实验是在早春期间对 8 头瘤胃插管的非泌乳奶牛进行的。四头奶牛通过放养 4 小时，持续 1 周（ADP 组）适应放牧。在此期间，其他奶牛被关在谷仓中（CON 组）。然后，两组奶牛在 1 公顷的牧场上全天放养 3 周（实验期）。_{实验第1周，与CON组相比，ADP组青草采食量、瘤胃NH 3} -N和总VFA浓度、血尿素浓度均高于CON组，而NEFA浓度低于ADP组（p  < .01）。在随后的几周内，瘤胃发酵参数和血液代谢物几乎没有差异。ADP 组的奶牛体重保持不变，而 CON 组的奶牛在实验期的第一周体重下降了 60 公斤。