Mich. Comp. Laws § 287.125

Sec. 5. Every dealer, broker, livestock trucker, or agent licensed under this act and carrying on or conducting business under the license shall at all times keep in or at the place of business or in each vehicle used by the licensee for the purpose of transporting livestock a copy of the license for inspection by any representative of the department, sheriff, undersheriff, deputy sheriff, state police or any other law enforcing agency. Each person licensed under this act that utilizes a vehicle, trailer, or other conveyance for the purpose of transporting livestock shall place and visibly maintain the required vehicle permit on the upper forward corner of the left side of the vehicle, trailer, or other conveyance.