LOUISVILLE, Ky. — After a tense review period that lasted nearly 22 minutes, after the apparent winning connections had already been interviewed on live television, the three stewards at Churchill Downs on Saturday made the difficult decision to disqualify Maximum Security for interfering with other horses around the final turn and gave the Kentucky Derby victory to the 65-1 shot Country House. In the 145-year history of the Derby, no other horse had lost a win for such an act.

Two riders had lodged objections against Maximum Security; the stewards did not post an inquiry. An objection is a claim of foul by a rider, a patrol judge or another racing official. The stewards, who oversee races for the Kentucky Horse Racing Commission and for Churchill Downs, got to work studying replays of the race, with millions of dollars riding on their decision. They analyzed every available angle of the race on screens in a tiny clubhouse office high above the racetrack.

This job has existed for ages in America’s oldest sport, essentially making stewards the pioneers of video review. Charged with protecting bettors, they stay out of sight and rarely speak to the news media, so it was an odd sight on Saturday when the stewards — Barbara Borden, chief steward of the Kentucky Horse Racing Commission; Brooks A. Becraft, a state steward; and Tyler Picklesimer, a track steward — were on the podium usually reserved for the winners of America’s biggest horse race.

Borden read a statement explaining the decision. She declined to take any questions. (The Kentucky Horse Racing Commission is a state government agency charged with regulating the conduct of horse racing and parimutuel wagering on horse racing and related activities.)