One
who muzzles an animal and threshes with it receives lashes and must pay
four cavs (6 liters) for a cow and three kavs for a donkey. But why
should it be so? The rule is that one does not receive lashes and pay
money for the same crime!
The proof is from the case of a son consorting with his mother who is a harlot.
Since the son is liable to the death penalty for incest, he is not
obligated to pay, and the sheep that he gave her should be considered a
present, not a payment. Since the Torah forbade that sheep as a
sacrifice, it must be that he is legally obligated to pay, only that it
is unenforceable in court. So too in the case of muzzling. 