1. Ruminant Nutrition and Emissions, Agroscope, 1725 Posieux, Switzerland
2. Research Contracts Animals, Agroscope, 1725 Posieux, Switzerland
3. Department Safety in the Food Chain, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
4. Laboratory for Advanced Analytical Technologies, Empa, Überlandstrasse 129, 8600 Dübendorf, Switzerland