Evaluation of indicators to assess the environmental impact of dairy production systems

Current awareness of environmental pollution of animal production in Western Europe has triggered research on development of environmental indicators at farm level. Only when the environmental impact of commercial farms can be quantified effectively, important differences in impact can be demonstrated among contrasting systems, which subsequently can contribute to reducing the environmental impact from animal production. Therefore, the aim of this study was to evaluate the effectiveness of environmental indicators derived from three methods used widely in animal production, i.e., input-output accounting, ecological footprint analysis and life cycle assessment (LCA). Evaluation of the effectiveness of indicators was based on an assessment of their relevance, quality and availability of data. Such a systematic evaluation of these environmental indicators has never been performed yet. To evaluate the effectiveness of the 13 environmental indicators, data from eight organic, commercial dairy farms in the Netherlands were used. Results show that indicators derived from input-output accounting are effective, because of their high relevance, good quality and easy availability of data. These indicators, however, do not include all environmental impact categories (e.g., land use, energy use, global warming potential), and focus on on-farm emission. The environmental indicator derived from ecological footprint analysis is not effective for land and fossil energy use, because of its limited relevance and low quality, whereas LCA resource-based indicators are effective because of their high relevance, good quality and availability of data. LCA indicators for global warming, acidification and eutrophication potential are effective also, because of their good relevance and good quality. Data of these LCA indicators are difficult to collect. To give a good insight into the environmental impact of a dairy production system, besides input-output accounting indicators, LCA indicators are required.