Reducing climate footprints and making milk production more sustainable is an urgent need for future dairying. Mitigating methane emission through specific feed practices and feed additives are intensively studied. A new project studies the effect of feed additives including 3-NOP and nitrate as well as fat supplementation on milk quality and functionality. Internationally, dairy labels based on grass-fed dairy cows have increasing market shares, and result from a Danish herd with 100% grass-feeding have documented higher milk vitamin contents and improved ω-3/ω-6 ratio. Furthermore, regulations demand a better monitoring of the N and P flow from farms to the environment, and optimizing protein supplementation in feed may go hand in hand with a growing interest for phasing out imported soy, and secure a more self-sufficient feed production for dairy cows. However, from a milk perspective, changes in N/P supplementation may also affect the protein-mineral balance in milk and thereby affect milk functionalities. Our primary aims are to document how these emerging strategies affect milk composition and functionality, and to secure that milk quality is not compromised in the search for more sustainable solutions for dairy production systems. Co-authors: Gayani M. S. Lokuge, Lars Wiking, Lotte Bach Larsen.Department of Food Science, Aarhus UniversityBart BuitenhuisCenter for Quantitative Genetics and Genomics, Aarhus UniversityMorten Maigaard, Peter Lund, Marianne JohansenDepartment of Animal Science, Aarhus University

 The four domains of sustainability are health, economics, society, and the environment. Healthy food patterns from sustainable food systems need to be nutrient rich, affordable, culturally acceptable, and appealing.  Sustainable foods systems, in turn, need to reduce their impact on the environment and help mitigate climate change. The current debate on personal, public and planetary health has been framed largely in terms of agricultural production and its environmental costs, still largely measured in terms of greenhouse gas emissions. Missing from the debate – and from the EAT Lancet report – were larger-scale considerations of affordable nutrition, global scarcity of high-quality protein, and the cultural, social, and economic value of livestock and dairy. These forgotten social and economic components of the sustainability framework deserve a closer look. Firstly, recommendations for a healthy global diet do not always concern themselves with food production or with food prices and diet costs, especially at the local levels. As a result, the recommended healthy diets ae not always feasible or affordable for the world’s poor. Economic feasibility metrics ought to accompany each set of dietary guidelines. Secondly, better metrics of the social and cultural value of foods are required. Preserving territorial food cultures and eating habits promotes social stability and cohesion in an increasingly fragmenting world. The economic viability of dairy farming worldwide needs to be addressed with respect to the UN Sustainable Development Goals on alleviating poverty and empowering women. Finally, environmental costs, still calculated per weight of food, need to be recalculated per 2000 kcal/d energy ration or better yet per 100% daily value of selected nutrients, including high quality protein. Balancing human nutrient needs, economic constraints, and societal values against the environmental impact of food production with require some trade-offs.