Mich. Comp. Laws § 750.65

Sec. 65. Any person being the owner of a bull 6 months or more of age or having the same in charge, who shall permit said bull to run at large upon any highway or unenclosed lands shall be guilty of a misdemeanor, and upon conviction thereof shall be punished by imprisonment in the county jail for not more than 30 days or by a fine of not more than $100.00, or both such fine and imprisonment in the discretion of the court.