The multivalve or ball claw was developed to prevent the detrimental effects on udder disease from both 'impacts' and 'cross contamination' during machine milking. Air-bleeds were fitted to the short milk tubes to achieve a milking action similar to conventional machines and in contemporary comparisons with conventional clusters the multivalve claw reduced total new infections by 14 per cent and clinical mastitis by 25 per cent. Subsequent research revealed that exclusion of air from the multivalve claw (hydraulic milking) produced the expected flooding of the liners and a milking action that was gentler to the teats and gave advantages in terms of milking performance, reduced lipolysis and milk sensing. Although the pulsation rates and vacuum levels developed for conventional milking appear to be suitable for hydraulic milking, recent research demonstrates that there are many possibilities for modifying and controlling the operating conditions so as to improve the milking performance and the control over the forces applied to the teats. The electronic monitoring of milk components during milking and the metering of milk yield may also be made simpler.