Bava Metzia 90 - Who Can Muzzle?
When one uses an ox to thresh wheat, one is not allowed to muzzle his ox, but must allow it to graze.
Naturally, this refers to all animals whom one works in the field. However,
One IS allowed to muzzle an animal that is suffering from diarrhea.
The prohibition of muzzling concerns what is good for its body, not to the anguish it feels from not being able to eat.
Can a man say to a non-Jew, "Muzzle my cow and thresh with it?" In general, can a Jew ask a non-Jew to do something forbidden to a Jew?
The answer is "No," based on the following ruling:
if a Jew had his bull stolen and castrated,
thus turning it into an ox, the Jew is penalized by having to sell his ox.
Art: Antonio Pisano Head of a muzzled dog