Environmental life cycle assessment of cow milk in a conventional semi-intensive Brazilian production system

Abstract

The environmental performance of cow milk produced in a conventional semi-intensive system was assessed using a cradle-to-farm gate attributional life cycle assessment. The impacts of 1 kg FPCM-fat and protein corrected milk were obtained considering six midpoint impact categories from the ReCiPe 2016 method: climate change (CC), terrestrial acidification (TA), freshwater eutrophication (FE), land use (LU), water consumption (WC), and fossil resource scarcity (FRS). The modeling of the product system and calculating the environmental impacts considered the use of SimaPro™ software. Enteric methane and nitrogen emissions and inputs for feeding animals (fertilization for pasture production, use of seed in corn crops, and milk replacer in calves feed) were the main contributors to impacts in milk production in most categories. In addition, the indirect energy use and wastewater generation in milking and milk cooling also were relevant. Literature-based strategies are suggested to mitigate the identified environmental impacts to achieve the best environmental performance without decreasing technical and quality milk production. We emphasize the importance of improving productivity per milk cow, knowing the origin of the supply chain inputs, and using it efficiently to produce animal feeds as the main strategies to improve milk's environmental performance. Changes in allocation methods did not substantially differ in impact categories. Sensitivity analysis foregrounds the consistency of results and conclusions of the current study despite the uncertainties associated with methodological choices, simplifications, suppositions, and the use and adaptation of international databases.

Keywords: Dairy chain; Environmental management; Impact assessment; Life cycle assessment; Life cycle inventory; Livestock; Milk.