The production of dehydrated alfalfa for animal feed requires substantial energy-consuming processes, which raises questions about the environmental sustainability of this sector; less energy-intensive processes and a transition to renewable energy are needed. In this study, we quantified the environmental footprint of dehydrated alfalfa production in France and its evolution over time using data collected over two periods (2006 to 2009 and 2016 to 2019). This study was based on twelve production units spread throughout the main alfalfa production areas in France, which represent more than 50% of the national production of dehydrated alfalfa. A life cycle assessment was performed for the three steps of this production: production in the field, transportation from the field to the factory and the dehydration process. This dataset contains the life cycle inventory data of these two periods, for the field and factory parts, as well as the data used for preparing the figures presented in the related article.