In a milking cluster of teat cups, each teat cup has a port in the form of a nozzle disposed in the head portion of the flexible liner (3) of the teat cup. The milking cluster includes a distributor having a fluid inlet aid outlets connected to the nozzles of the cups. The distributor inlet is connected to a supply of filtered air under atmospheric pressure by a first valve which is operable to admit air to the distributor in order to regulate the level of vacuum present in the teat cup liners during a milking cycle. It is connected to a delivery line for supplying sanitising fluid, which is utilised to treat the teats and teat cups in a cleansing cycle following the milking cycle, by a second valve operable to maintain the delivery line primed with sanitising fluid preparatory to initiation of the cleansing cycle.