Wis. Stat. § 562.075: Horses foaled in this state; three-year-old horses.

(1) Horses foaled in this state. Every licensee to sponsor and manage horse races under s. 562.05 (1) (b) or (c) shall hold at least one race on every race day which is limited to horses foaled in this state, except that another race may be substituted if the licensee is unable, with reasonable effort, to attract sufficient competition for such a race. The department shall define, by rule, the term “foaled in this state”.

(2) Three-year-old horses.

(a) Definition. In this subsection, “3-year-old horse” means a horse which was foaled during the 3rd year immediately before the year in which the horse participates in a race.

(b) Races. Every person licensed to sponsor and manage horse races under s. 562.05 (1) (b) or (c) shall hold at least one race, on every race day, which is limited to 3-year-old horses, which did not race during the prior 2 years. If the licensee is unable, with reasonable effort, to attract sufficient competition for such a race, another race may be substituted.