The effect of grazing system and level of concentrate protein feeding on milk production and N use efficiency of dairy cows on peat meadows

Abstract

The aim of the study was to assess the effect of two contrasting grazing systems, strip-grazing and kurzrasen, at a high stocking rate on herbage intake and milk production and quality on a peat meadow. Additionally, we assessed the effect of the level of crude protein (CP) fed in concentrate on milk production and N use efficiency. Even at the relatively high stocking rates, cows still achieved substantial fresh grass intake (on average >6 kg dry matter cow-1 day-1) from both systems. Despite the lower level of gross grass production under kurzrasen management, the difference in milk production between kurzrasen and strip-grazing was small and non-significant. Feeding concentrate with a lower CP level, had no negative impact on milk yield, provided that the CP content of the total ration remained above ~150 g kg-1 DM and milk urea content was above ~18 mg 100 g-1 milk. Reducing the CP content in the concentrate significantly increased the N use efficiency, and both were strongly related to the milk urea content. Therefore, optimising the use of milk urea as a management tool on dairy farms, also during the grazing season, could reduce N losses to the environment, while maintaining productivity.