There is provided a distributor device (22) for distributing treatment fluid to the teat cups of a milking cluster. The distributor device has at least one distributer inlet (18) for treatment fluid, at least one distributor outlet (20) for connection to a teat cup, and a safety valve The safety valve is selectively operable to permit flow between the at least one inlet (18) and the at least one outlet (20) and, in a rest position, to shut off flow between the at least one inlet and the at least one outlet and vent the at least one inlet to atmosphere.