Future of animal nutrition: the role of life cycle assessment

The livestock sector poses severe pressure on the environment via the emissions of pollutants to air, water and soil, and via the use of scarce resources. This chapter elaborates on the role of life cycle assessment (LCA) to reduce environmental impacts of the pig and poultry sector, with special emphasis on the production of feed. First, the four phases of an LCA are described. Differences between attributional and consequential LCA, and variability in methods to account for land use change are discussed. It is concluded that harmonisation of methods and high quality inventory data are needed to improve interpretation of LCA results in the livestock sector. Second, the role of LCA in animal nutrition is discussed. Improving the production efficiency of crops and animals has been a major focus for reducing environmental impacts of livestock production. LCA implicitly combines information regarding crop and animal productivity, and creates understanding about the interaction between processes, and the impact of the entire production chain. Current applications of LCA are mainly attributional; results create understanding concerning the current situation, such as the environmental impact of a certain diet. To evaluate the impact of improvement options, consequential LCA is required. If a feed company increases its use of by-products, for example, the consequences of a decrease in availability of that by-product for other applications, such as biofuel production, need to be taken into account. A potential shortcoming of LCA is that is does not address the competition for resources between humans and animals, which occurs at a higher aggregation level. To determine an environmentally sustainable human diet, or to address the role of livestock in (global) food security, LCA needs to be combined with other modelling techniques that address environmental impacts of dietary choices at the national or international level