1. Institute of Animal Science; University of Bonn; Bonn Germany
2. Chamber of Agriculture of North Rhine-Westphalia; Bad Sassendorf Germany
3. Experimental and Educational Centre for Agriculture ‘Haus Riswick’; Chamber of Agriculture of North Rhine-Westphalia; Kleve Germany
4. Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences; Humboldt-Universität zu Berlin; Berlin Germany
5. LKS Landwirtschaftliche Kommunikations- und Servicegesellschaft mbH; Lichtenwalde Germany