This study conducts a review bringing together data from a large number of studies investigating energy use in EU livestock systems. Such a study has not been conducted previously, and improvements in our understanding of energy use concentrations in livestock systems will aid in developing interventions to achieve the EU’s 2030 and 2050 sustainability targets. The results from the Life Cycle Assessments included in this review indicate that energy use is concentrated in feed, housing, and manure management. In most systems, animal feed is the dominant energy use category. Regarding specific livestock categories, the studies covered indicate that energy use requirements range from 2.1 to 5.3 MJ/kg per ECM for cow milk, 59.2 MJ/kg for a suckler cow–calf, and 43.73 MJ/kg for a dairy bull, 15.9 MJ/kg to 22.7 MJ/kg for pork production, 9.6 MJ/kg to 19.1 MJ/kg for broiler production, 20.5–23.5 MJ/kg for chicken egg production. Our review indicates dominance of and dependence on fossil fuel and discusses the situation and research around transitioning towards renewable energy sources and improving energy efficiency. Our analysis indicates that existing energy use data in livestock systems are fragmented and characterized by multiple methodologies and considerable data gaps. In our view, there is a need for the development of a standardized methodology for measuring energy use in livestock systems, which we consider a necessary step to develop interventions that reduce fossil energy use in livestock systems and its contribution to climatic change.