Environmental Sustainability of Dairy Cattle in Pasture-Based Systems vs. Confined Systems

The aim of this paper is to review the literature on the environmental impacts of pasture-based dairy cattle systems, focusing on the factors affecting the main impact categories. This paper also aimed at comparing data of the literature on environmental impacts in pasture-based vs. confined systems. The environmental impact of pasture-based dairy cattle systems appears to be highly influenced by several input factors. Life cycle assessments have shown significant variability in methodological approaches, which complicates the comparison of results across studies. The different variables affecting environmental impacts make it challenging to draw universally valid conclusions regarding the comparison of pasture-based and confined dairy systems on a global scale. In addition, the analysis of the variables highlights the considerable potential to reduce the environmental impact of milk production in both systems by adopting productivity-enhancing activities, low inputs and best management practices. Further aspects such as geographical factors, carbon sequestration, animal health and welfare, toxicological aspects due to the use of drugs and antimicrobials in animals and the maintenance of local animal breeds should be incorporated into LCAs for a full comprehensive understanding of the environmental impacts of dairy farms.