1. Grass and Forage Science/Organic Agriculture, Christian-Albrechts-Universität zu Kiel, 24118 Kiel, Germany
2. Natural Chemistry Research Group, Department of Chemistry, University of Turku, Vatselankatu 2, FI-20014 Turku, Finland
3. Grass Based Dairy Systems, Animal Production Systems Group, Wageningen University (WUR), 6708 PB Wageningen, The Netherlands