4 Animal Health Research Center (CISA), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Consejo Superior de Investigaciones Científicas (CSIC), Valdeolmos, 28130, Madrid, Spain.
5 Unit of Nutrition and Health, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
6 Unit of Anatomy, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway. Electronic address: erling.o.koppang@nmbu.no.