Is low-input dairy farming more climate friendly? A meta-analysis of the carbon footprints of different production systems

摘要: Abstract The global warming potential of milk production is a key aspect in the assessment its eco-efficiency. carbon footprint summarises climate-relevant emissions cycle, with this study focussing on from cradle to farm gate as boundaries. Numerous life cycle assessments were published recent years, presenting for different regions, systems and management scenarios. However, despite obvious high scientific interest topic, general conclusions climate-friendliness contrasting can hardly be drawn there no clear answer question whether or not grazing provide an overall more climate-friendly alternative confinement systems. To resolve discussion, meta-analysis was applied dataset, created data selection 30 assessments, comprising total 87 values 15 countries. After standardisation process, three system categories (pasture-based, mixed confinement) defined based feeding parameters. Aside comparison systems, effects various variables (pasture concentrate intake, yield per cow, kg metabolic live weight, mineral nitrogen fertilisation, feed efficiency replacement rate) analysed. Therefore, linear level-log models developed analyses covariance performed. As dataset used analysis covered large range intensities system, results are robust extrapolated any known in- outputs. show that increases yield, pasture intake decreased significantly, independent system. mitigation limited across regard their productivity thresholds. without consideration other parameters did reveal significant differences. When controlling however, pasture-based achieved lower footprints compared Thus, irrespective importance generally yields still offers competitive climate impact.