Leviticus 22:21, 23

And when anyone offers a sacrifice of peace offerings to the LORD to fulfill a vow or as a freewill offering from the herd or from the flock, to be accepted it must be perfect; there shall be no blemish in it.

You may present a bull or a lamb that has a part too long or too short for a freewill offering, but for a vow offering it cannot be accepted.