Milkmaid

A milkmaid (or milk maid) was a girl or woman employed to milk dairy cows. She also used the milk to prepare dairy products such as cream, butter, and cheese. Many large houses employed milkmaids instead of having other staff do the work. The term milkmaid is not the female equivalent of milkman in the sense of one who delivers milk to the consumer; it is the female equivalent of milkman in the sense of cowman.

The expression "as smooth as a milk maid's skin" means exceptionally smooth. This phrase came about as a result of exposure to cowpox, which causes no serious symptoms, but does convey a partial immunity to the disfiguring (and often fatal) disease smallpox. Thus, milkmaids lacked the "pockmarked" complexion common to smallpox survivors. This observation led to the development of the first vaccine.

...
Wikipedia