Milk, an example of staple food, has an outstanding demand by consumers as it is considered a prescription for good health. Life cycle assessment (LCA) is an excellent tool of environmental management and it provides a widespread knowledge on the environmental burdens associated to a product or to a human activity. In this study, a simplified methodology of LCA has been applied to analyse a representative scheme of milk production in Galicia (Spain), where a reliable inventory is still lacking. High quality data for the inventory was obtained in different representative fodder factories, farms and dairies for time periods over two years. The analysis of these data by LCA has permitted to quantify the potential impact associated to milk production and also to determine the reductions attained by the application of different improvement actions, such as the most adequate formulation of cattle feed and the implementation of treatment systems for water and air emissions. The consideration of these actions can lead to a maximum reduction of almost 22% of the global normalised impact.