It is known to use rotary platforms for milking dairy cows, having an annular deck supported on at least one circular beam. Rollers take the weight of the beam as it moves in a rotary manner. Loads on the platform can lead to deterioration of the rollers. Replacing the rollers can be unduly inconvenient and time consuming. It is an object of a preferred embodiment of the invention to go at least some way towards addressing this problem. A preferred embodiment of the invention comprises a rotary milking platform having a deck 2, an upper beam 4, a lower beam 6 and a ring of carriages rotatable between the beams. Each carriage 5a has at least a pair of carriage rollers 10 with a side flange 11. The flanges 11 of each pair are at opposite sides of their carriage and prevent the carriages from moving off the lower beam when the platform is in use. At least some of the carriages can be disconnected and swung laterally to move their rollers 10 free of the beams 4, 6 for replacement.
