Five forage crop rotations at two intensification levels have been compared using energy analysis, to have an integrated view on the systems under study. Inputs required by the five rotations ranged from 33 to 72 GJ•ha-1•yr1• Outputs from cropping systems ranged from41 to 153 GJ•ha-1•yr1 and output/input ratios from 1,25 to 2,13. The most efficient rotations in terms of net energy production efficiency have been characterised by reduced length and presence of maize and catch-crops. Low intensification level has caused higher efficiency in three rotations