Increasing herd size and fragmented or non-uniform land challenge pasture-based milk production systems. Therefore, part-time grazing combined with indoor feeding of fresh herbage (‘cut-and-carry’) allows to maintain the advantages of fresh-herbage-based diets. However, consequences for environmental nitrogen losses, animal behaviour and ruminal metabolism are decisive for its implementation. Animal performance, nitrogen use efficiency (NUE), reticulo-ruminal pH and feeding/locomotive behaviour were compared in six cows subjected either to full-time grazing (system F) or to part-time grazing system with indoor feeding of fresh herbage and concentrate (system P). Biweekly samplings were performed on six lactating cows per treatment in spring, summer and autumn. Nitrogen (N) balance was calculated from estimated N intake and N output via faeces, urine and milk. Reticulo-ruminal pH was recorded using a wireless data recorder. Eating and locomotive behaviour were measured with noseband sensors and pedometers. In spring, but not later, herbage intake per unit of body weight was higher for system F compared to system P cows. Eating time was shorter by 15% in P compared to F cows. Across systems, NUE declined from spring to summer/autumn from about 300 to 200 g milk protein N/kg N intake. Reticulo-ruminal pH was more variable under part-time grazing conditions, with a pronounced decrease subsequent to offering the herbage indoors. The part-time grazing system resulted in similar or higher NUE than full-time grazing. Additional studies with larger numbers of experimental units are required to be able to develop comprehensive recommendations for the improvement of the two grazing systems.

中文翻译：

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全日制或非全日制放牧奶牛的氮利用效率、网状瘤胃pH和行为，室内饲喂新鲜牧草和浓缩物

畜群规模的增加和分散或不均匀的土地对以牧场为基础的牛奶生产系统构成了挑战。因此，非全日制放牧与新鲜草本的室内饲喂相结合（“切割和携带”）可以保持以新鲜草本为基础的日粮的优势。然而，环境氮损失、动物行为和瘤胃新陈代谢的后果对其实施具有决定性意义。动物性能、氮利用效率 (NUE)、网状瘤胃 pH 值和摄食/运动行为在 6 头奶牛中进行了比较（系统 P）。在春季、夏季和秋季，每次处理对六头泌乳奶牛进行双周取样。氮 (N) 平衡是根据估计的 N 摄入量和通过粪便排出的 N 计算得出的，尿液和牛奶。使用无线数据记录仪记录网状瘤胃 pH 值。使用鼻带传感器和计步器测量进食和机车行为。在春季，但不是以后，系统 F 的每单位体重的草料摄入量高于系统 P 奶牛。与 F 奶牛相比，P 奶牛的进食时间缩短了 15%。在整个系统中，从春季到夏季/秋季，NUE 从大约 300 到 200 g 牛奶蛋白 N/kg N 摄入量下降。在兼职放牧条件下，网状瘤胃的 pH 值变化更大，在室内放牧后显着降低。与全日制放牧相比，兼职放牧系统的 NUE 相似或更高。需要对更多的实验单位进行额外的研究，以便能够为改进这两个放牧系统制定全面的建议。