Mich. Comp. Laws § 287.111

Sec. 1. As used in this act: (a) "Department" means the department of agriculture. (b) "Riding stable" means any establishment in which, for business purposes, 6 or more horses or ponies are rented, hired, or loaned for riding. (c) "Sales barn" means any establishment where horses or ponies owned by others are sold or offered for sale.