The Effect of Grazing System and Level of Concentrate Protein Feeding on Milk Production and N Use Efficiency of Dairy Cows on Peat Meadows

Nyncke Hoekstra,René Schils,Gertjan Holshof,Ronald Zom,Bert Philipsen,Nick Van Eekeren

doi:10.3390/su12031055

Nyncke Hoekstra, René Schils + Show 4 more

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https://doi.org/10.3390/su12031055

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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.

Highlights

In northwestern Europe, grazed pastures form an important feed source for dairy production and grazing cows are important for the image of the dairy sector [1]
The experimental treatments consisted of two grazing systems, two (2016, low and high crude protein (CP)) or three (2017, low, medium and high CP) levels of CP in the concentrate feed, and two cow breeds (Holstein Friesian = HF, Jersey = J) in a factorial design
There was no significant effect of grazing system on milk CF and CP content and on liveweight change and BCS (Table 4)

Summary

Introduction

In northwestern Europe, grazed pastures form an important feed source for dairy production and grazing cows are important for the image of the dairy sector [1]. In the Netherlands, in recent decades, herd size has nearly doubled from 55 to 97 dairy cows per farm [2], whereas the available grassland area close to the farm yard remained the same [3] This results in high(er) stocking rates on the grazed area, often in excess of 7.5 cows per ha, which makes it difficult to maintain a grazing system with access to pasture for more than six hours per day [3]. The regrowth period between grazings may vary from two to three weeks depending on herbage growth rate and supply This system generally results in the highest grass production and milk production. It is associated with relatively large investments in grazing infrastructure (cow paths and watering points) and labor requirements for moving fences, water supply and grassland planning

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