"‘Clean that udder good, now.’ Roskus said. ‘You milked that young cow dry last summer. If you milk this one dry, they ain’t going to be no more milk.’"
Hand-milking
Creative Commons AttributionHand-milking - Credit: Denis Gustavo
Udder of a dairy cow
Creative Commons AttributionUdder of a dairy cow - Credit: Julia Rubinic

Although it is important to keep a cow’s udder well-washed as uncleanliness imparts an unpleasant flavour to the milk, Roskus is in fact advising T. P. to make sure he squeezes every last drop from it. In Cottage Economy (1822) William Cobbett states: “If you do not milk clean, the cow will give less and less milk, and will become dry much sooner than she ought.” A further incentive to thorough milking is that the last half-pint is the richest and best, and leaving any fluid in the udder contributes to its chances of becoming diseased.