1 Research Institute for Farm Animal Biology (FBN), Institute of Nutritional Physiology "Oskar Kellner", Dummerstorf, Germany. Electronic address: b.kuhla@fbn-dummerstorf.de.
2 Dairy Research and Innovation Centre, Scotland's Rural College (SRUC), Parkgate, UK.
3 Animal Nutrition Group, Wageningen University and Research, Wageningen, the Netherlands.
4 School of Agriculture, Policy and Development, University of Reading, Earley Gate, United Kingdom.
5 Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy Co. Cork, Ireland.
6 Department of Animal Science, Aarhus University, Tjele, Denmark.
7 Université Clermont Auvergne, INRAE, VetAgro Sup, UMR Herbivores, Saint Genès Champanelle, France.
8 Department of Ruminant Production, IRTA (Institut de Recerca i Tecnologia Agroalimentàries), Caldes de Montbui, Spain.