No stallion over one year old, nor bull over 6 months old, nor boar, nor ram, nor billy goat over 4 months old shall run at large. If the owner or keeper of an animal described in this section, for any reason, permit the animal to run at large, the owner or keeper shall forfeit $5 to the person taking up the animal and shall be liable in addition for all damages done by the animal while at large, regardless of whether the animal's escape was the fault of the owner or keeper. The construction of any fence enumerated in s. 90.02 does not relieve an owner or keeper from liability for any damage committed by an animal described in this section upon the enclosed premises of an adjoining owner.
Wis. Stat. § 172.01