Dr Nico van Belzen is Director General at ScienceConsult, The Netherlands. He is also former Director General of the International Dairy Federation (IDF), Belgium. He has occupied senior roles in both industry and research organisations, both as Head of the Research and Analysis department at the ingredients division of Campina and as Executive Director of the European Branch of the International Life Sciences Institute (ILSI). Dr van Belzen is editor of two earlier Burleigh Dodds Science volumes: Achieving sustainable production of milk Volume 1: Safety, quality and sustainability and Achieving sustainable production of milk Volume 2: Milk composition, genetics and breeding (both published in 2017).Dr Bernadette O'Brien is a Senior Research Officer at Teagasc Moorepark's Animal and Grassland Research and Innovation Centre in Ireland. Dr O'Brien has also been involved in coordinating successful applications for research funding to National and EU (Seventh Framework) programmes. Dr O'Brien has published extensively and has significant international collaborations with research scientists at Agroscope, Switzerland; Massey University and Dexcel in New Zealand and Wisconsin University (Madison), USA. Dr Mette Vaarst is a Senior Researcher in the Department of Veterinary and Animal Sciences at Aarhus University, Denmark. She has published extensively on organic animal farming, coordinated several European research projects and co-edited Improving organic animal farming, published by Burleigh Dodds Science Publishing in 2019.