I have the impression that many tales about witches are about them stealing milk and butter, and sometimes going to great lengths to do this (see "Tilberi"). Or they bewitch animals to stop giving milk (and give blood instead). Or they make milk go sour. Or they do something else involving milk and butter...
At least European witches seem to do this, since I found quite a few examples in my German mother tongue, but next to nothing in English.
How come? Was butter that important and expensive during "the time of the witches"? Is this something about witches being female and doing or ruining woman's work with magic?
Examples:
Many European peasant societies at the time of the witch craze placed value on the dairy industry, and whenever the production of milk seemed to decrease, it was easy to blame a supernatural agency. Witchcraft was an obvious way to explain an economic crisis of this sort, since it was easy to imagine someone using magic to take the milk supernaturally - or at least to take the best of its essence.