A method for minimising the power requirement of a vacuum system of a vacuum operated milking system and an apparatus for operating a vacuum operated milking system for minimising the power requirement of the milking system are disclosed. The apparatus comprises a control means (60) for operating the milking system with the vacuum demand by a pulsating vacuum generator thereof reduced. The control means is responsive to the milking system being operated in a cleaning cycle for operating the milking system with the vacuum demand by the pulsating vacuum generator reduced for a time period during at least a portion of a cleaning cycle, at least while the vacuum demand by the milking system is greatest. Also disclosed is a vacuum operated milking system (1) operable in a milking mode and a cleaning mode, and in the cleaning mode the milking system is operable in a cleaning cycle. The milking system comprises a main milk pipeline (2) extending between an upstream end (3) and a downstream end (4) and terminating at the downstream end in a receiving means (5), a plurality of milking clusters (9) coupled to the main milk pipeline at spaced apart intervals between the upstream end and the downstream end thereof, a vacuum system (8) coupled to the main milk pipeline through the receiving means for applying a vacuum to the milking clusters for drawing milk from the milking clusters through the main milk pipeline to the receiving means, a pulsating vacuum generator (24) coupled to the vacuum system for applying a pulsating vacuum to the milking clusters, and the above described control means for selectively operating the milking system with the vacuum demand by the pulsating vacuum generator reduced.
