The original story of the white cow:

A farmer is being interviewed about his cows

reporter: what do you feed the cows?
farmer: the white or the black one ?

the white one.
hay.

-and the black one?
-also hay.

where do they sleep?
-the white or the black one?

.....the white one!
in the barn

-and the black one ???
also in the barn.

- WHY DO YOU HAVE TO ASK WHICH ONE IM REFERRING TO IF THE ANSWER IS THE SAME FOR BOTH OF THEM??
-oh please forgive me but the WHITE one is mine.

-and the black one??
-also mine.