Effect of variation of vacuum level on milking rate of Australian Illawarra Shorthorn cows

Abstract

Increasing the vacuum level from 10 in. to 16 in. increased the maximum milking rate and the overall milking rate. The increase in maximum rate was slightly greater for faster milking cows than for slower milkers.
Considerable variation in milking rates was found between cows. Faster milkers milked faster at 10 in. than did slower milkers at 16 in. Rates are compared with those reported by other workers for other breeds of cows.
Neither the amount of strippings nor stripping time appeared to be related directly to vacuum level. The vacuum at the teat-cups approached the unit vacuum only towards the end of the milking period. The teat-cup vacuum during the period of fastest milking showed little difference with milking vacuum levels of 12, 14 and 16 in. for the fastest milking cows.