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.

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For this research communication our objective was to investigate to what extent milk coagulation properties and milk fatty acid (FA) composition were affected by different feeding systems, season and their interaction. Eighteen cows in total were subjected to one of three different feeding system treatments: full-time grazing or part-time grazing combined with indoor feeding of fresh grass with low or high concentrate supplementation. Milk was sampled in spring, summer and autumn. Milk coagulation time was 15.0, 19.0 and 17.7 min, coagulation dynamics 1.67, 3.41 and 1.79 min, and curd firmness 52.7, 32.4 and 47.0 mm in spring, summer and autumn, respectively. Thus, milk coagulation properties of the milk were lower during summer. There were strong seasonal effects on milk FA proportions, but there were not always changes with progressing season, or changes were different with respect to the impact of the feeding systems (system × season interaction). The milk fat was favourably rich in oleic acid, conjugated linoleic acid and α-linolenic acid and had a low n-6/n-3 fatty acid ratio in all systems. Factors like seasonal variations in grass composition and the energy balance of the cows were considered relevant for the milk FA composition. Overall, seasonal variations in milk quality were less pronounced with part-time grazing with fresh grass indoors as compared to full-time grazing without concentrate.

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