Evaluation of the overall environmental life cycle sustainability of nutritional strategies to reduce emissions of methane and nitrogen at dairy farms in Flanders (Belgium)

Livestock’s contribution to global warming, mainly due to enteric methane emissions, is one of the major environmental issues that has to be tackled. Although multiple mitigation opportunities were identified (Gerber et al., 2013), a large need exist to test and evaluate these mitigation strategies in country- and region-specific conditions. In this work, we focus on nutritional strategies to reduce methane emissions at dairy farms in the region of Flanders (Belgium). Reduction of environmental impacts throughout the production chain, from feed production, over feed digestion, until milk production, is crucial to ensure that greenhouse gas emissions are in fact reduced and to avoid environmental problem shifting. We therefore assess the environmental sustainability of the applied nutritional strategies from a life cycle perspective, retrieving data from in vivo measurements of both methane and nitrogen emissions. Also, as Huysveld et al. (2015) has shown that resource use intensity differs among and between different types of feeds (roughages, concentrates, by-products), we evaluate natural resources consumption (land, water, fossil resources, minerals, metals, etc.) of the feed production chains, using an exergy-based resource accounting method. In this way, effective nutritional mitigation strategies can be identified and will be implemented in practice at dairy farms.