At a recent milking time visit to a high yield herd, I noticed mean claw vacuums during our milking time testing often getting as low as 30 – 32 kPa during peak milk flow, despite the system vacuum being 46 kPa on a mid-level installation The national mastitis Council recommends average claw vacuums between 36 and 42 kPa during peak milk flow, it was very important to understand what was going on. The milking machine can transmit infection onto teats and disturb normal teat health, quantifying the degree to which the milking machine might be contributing to the risk of new intra-mammary infection. Cows’ teat size and position have changed as have milk flow rates. Milk yields have been rising faster than unit attachment times. Milk flow rate has been shown to be positively associated with risk of new intra-mammary infection “Milking time testing” A milking-time test is a test performed while milking cows and with the milking system under normal use conditions. Some cows had been achieving milk flow rates approaching 7.5 litres/min. This is quite high for typical British cows, where flow rates often don’t exceed about 5 litres/min. The milking machine had a claw capacity of 220 litres with an 8 litre bleed from the claw the length of milk tube was over 3 meters with an inline cut off valve and in line automatic cluster remover canister The long milk tube was supposed to be 12.5 mm internal diameter , the real diameter measured was 11mm ,the slug length was excessive, however the Variable Speed Drive was not installed correctly and the recovery was affecting the vacuum drop by as much as 10 kpa . The pulsation rate was 49ppm .