What type of horses run in the Kentucky Derby?

Feb 14, 2024 Kellie Reilly/TwinSpires.com

So what qualities do these elite Kentucky Derby contenders have?

• Three-year-old Thoroughbreds
• Precocious enough to lay a foundation at two
• Progress from two to three
• Earn points in a series of designated qualifiers
• Ability to run fast over a distance
• Stay healthy

As America’s iconic horse race, the Kentucky Derby (G1) is the ultimate prize that everyone wants to win. From global industry titans to small-time breeders, Hall of Famers to hard-scrabble trainers and jockeys, and fans with rooting interests, there’s nothing like having the Derby winner.

Precisely because of its unique prestige, it takes a special horse just to make it to the starting gate at Churchill Downs on the first Saturday in May. From a crop of about 20,000 foals (in North America), only 20 – at most – can compete in the “Run for the Roses.”

Let’s start with the basic prerequisites, then advance through the various thresholds to qualify.

Three-year-old Thoroughbreds

Every race has certain conditions of eligibility, and the Kentucky Derby is strictly for Thoroughbreds who are three years old. That’s why it’s the “chance of a lifetime in a lifetime of chance,” as the Dan Fogelberg song says. A horse has just one window of opportunity, and there’s no “next year” to try again.

Although there are other breeds that race, such as Arabians, Quarter Horses, and Standardbreds (the harness horses who pull sulkies), the Thoroughbred is the quintessential racehorse. Refined through selective breeding over centuries, the Thoroughbred gallops faster than its venerable ancestor, the Arabian, and carries that speed a lot farther than the Quarter Horse.

The Derby’s age qualification refers to three-year-olds in the Northern Hemisphere, whose official birthday is universally reckoned as Jan. 1. Three-year-olds foaled in the Southern Hemisphere do not qualify because they would actually be several months older, based on the breeding season in their part of the world.

Precocious enough to lay a foundation at two

Youngsters have to be forward enough to get some foundation as two-year-olds, or else they won’t be able to develop in time. Normally, that means racing experience as a juvenile. Horses can begin racing at three and still make the Derby, if everything goes right, but a late start remains an historical obstacle to winning the roses. No horse in 136 years had managed to capture the Derby after being unraced at two, until Justify (2018), and it remains to be seen how long it will take for another to emulate him.

Yet, even Justify had been in serious training at two, logging workouts regularly through the fall before launching his career. If a juvenile isn’t ready to lay that bare minimum of a foundation, he won’t be ready to try the Derby trail, no matter how much natural ability he has. The best recent example is Flightline, who needed plenty of time at two. The Derby was therefore never on the cards for Flightline, but he became an unbeaten phenom and eventually Horse of the Year as a four-year-old.

Progress from two to three

Some horses are so precocious that they’re physically peaking as two-year-olds. These are not the type to make it to the Derby, though. Their comparative advantage diminishes over time, as their rivals grow stronger, catch up to them developmentally, and surpass them.

Derby prospects come from the pool of youngsters who have the scope to improve from two to three. Many times, they can be a bit bigger-framed, and need to fill out to reach full strength. Or perhaps they’re mentally immature, but figuring things out along the way. Horses who show talent early, along with these various signs of more to come, are the right sort of candidates.

Earn points in a series of designated qualifiers

Aspirants qualify by performing well in designated “Road to the Kentucky Derby” races, where they compete for points awarded to the top five finishers on a sliding scale. The scoring races start for juveniles in September, with the Iroquois (G3) at Churchill Downs as a fitting kickoff, and end in April.

As the trail heats up through the spring, the points increase. The final major preps are worth a total of 200 points; the winner receives 100 points, more than enough to guarantee a Derby berth.

This same concept has been expanded to two international series, the European Road and the Japan Road. Each has its own separate leaderboard, and only one horse can earn the Derby invitation for that international Road.

Ability to run fast over a distance

Prep races test the Derby hopefuls for both speed and stamina. The right combination is required for the 1 1/4-mile Kentucky Derby, the longest race these horses will have tried at this point. While the horse’s ancestry (pedigree) can offer clues, many won’t live up to what their parents or grandparents did, and less fashionably-bred runners can exceed expectations. The individual has to speak for himself, as it were, on the racetrack.

Some horses are brilliantly fast, but at shorter distances. They will be found out in the scoring races, especially those at 1 1/8 or 1 3/16 miles. Other horses can go long, but aren’t fast enough to be competitive at a high level. Their capacities may increase with maturity, well past Derby time.

Derby contenders have established an ability to run fast enough, in good company, over a route of ground. They could be horses with high cruising speed, like Triple Crown champions American Pharoah and Justify, or closers who hit top gear in the stretch.

Stay healthy

If a promising three-year-old has passed these tests and earned enough points to qualify for the Derby, the mission isn’t quite accomplished. The horse has to avoid any setbacks, however minor, that could knock him out.

Derby history is filled with stories of highly-regarded contenders missing their date with destiny because of an ill-timed issue. Whether it’s illness, foot trouble, or other injuries, horses are like human athletes who can come up with a problem that sidelines them by game day.

Hence, it’s a significant accomplishment for a young horse to achieve all of these objectives, in a compressed time frame, and run in the Kentucky Derby.