It is forbidden to tie a horse to the sides of a wagon or to the back of a wagon, or [to tie] a libdicum to camels. Rabbi Yehudah says: All those born of a mare, even though their father is an ass, are permitted one with another; and so also those born of an ass, even though their father is a horse, are permitted one with another. However, those born of a horse with those born of an ass are forbidden with one another.