In a world in which food and energy needs go on increasing, the development of methodologies that limit the impact of their production is more important every day. A correct evaluation of the impact is fundamental to obtain an actual reduction in emissions from the systems. This thesis presents an integrated Life Cycle Assessment of dairy and biomethane production chains, with the goal of identifying the most influential choices and factors in their Carbon Footprints and exploring how they interact. After an analysis of the relevant regulations, a scenario-based approach was adopted to assess the effects of different farming choices on emissions from the system.