Wis. Stat. § 173.25

A political subdivision, a person contracting under s. 173.15 (1), a humane officer or a law enforcement officer who has reasonable grounds to believe that s. 173.23 (1m) (c), (4) or (5) or a court order issued under s. 173.23 (3) authorize an animal to be euthanized is not liable for damages for the loss of the animal resulting from euthanizing the animal.