This disclosure generally relates milking systems and, in particular, automatic milking systems. The disclosure presents methods, apparatuses and computer program for providing a reference value to be used for controlling a calibration of at least one milk meter in a milking system. In accordance with one embodiment, a method may comprise obtaining (510) milk flow data for a plurality of milking animals to determine a milk flow profile for each milking animal of the plurality of milking animals; comparing (520) the determined milk flow profiles to establish a subset of milk flow profiles that meets a pre-defined selection criteria; determining (530) said reference value based on the established subset of milk flow profiles; and providing (540) the determined reference value for controlling a subsequent calibration of at least one milk meter in a milking system.