It would be more than enough for any breeding operation to come up with a superstar runner such as Nitrogen, but she represents only part of the collection of stakes winners for whom D. J. Stable is responsible this season.
The racing and breeding outfit, owned by the father-son team of Len and Jonathan Green, has had a hand in several other possible starters in the Oct. 30-31 Breeders' Cup World Championships at Keeneland.
The Greens, including Len's late wife, Lois, who died in 2023, decided to scale up their longtime breeding arm into a more commercial concern some eight years ago. They shifted to a plan that concentrated on developing fillies who could graduate from the racetrack into their breeding program, and then perpetuate the cycle.
"Our program has evolved over four decades," noted Jonathan Green. "We started as a claiming operation that kept some of those horses to breed to regional stallions. But we weren't really getting anywhere, so we decided to acquire better-bred fillies, race them, and then breed them to proven stallions. And we're starting to see the fruits of that labor with the stakes and graded stakes horses coming along now."
Homebred Nitrogen is the poster girl for the Greens' success. They landed her dam, the winning, stakes-placed Uncle Mo mare Tiffany Case, for $320,000 at the 2019 Keeneland November Breeding Stock Sale in foal to Violence . The resulting filly, Love to Shop, became a D. J.-bred stakes winner. But Tiffany Case's second foal, Nitrogen (by Medaglia d'Oro), has turned into the real breadwinner.
Conditioned by Mark Casse, Nitrogen has amassed $3,068,354 in earnings heading into her start in the Breeders' Cup Distaff (G1), a race in which she finished second a year ago. She was crowned last year's champion 3-year-old filly, and has kept up her winning ways this season. She enters the Distaff off victories in the Ogden Phipps (G1) and Beldame (G2) stakes, as well as a gutsy runner-up effort to Sovereignty in the Whitney Stakes (G1), in probably the best open field assembled this year to date in North America.
"We proved to ourselves and the rest of the industry that she could go head-to-head with the best horses, male or female, in training this year," Green said. "There are a lot of nice fillies and mares in the Distaff, but she will be a deserving favorite."
Green added that as long as Nitrogen stays sound and wants to keep competing, she will be campaigned in 2027 as a 5-year-old before a decision is made on whether or not to enter her at auction. The Greens have a 2-year-old Gun Runner half sister to Nitrogen named Sniper who is in training with Casse and who will be retained for the broodmare band. At this year's Keeneland January Horses of All Ages Sale, the Greens parted with Tiffany Case (in foal to Not This Time ) for $3.2 million as she was purchased by Whisper Hill Farm.
Also carrying the banner for the Greens' breeding operation into the Breeders' Cup is Haffner, a 2-year-old Justify colt co-bred with the Coolmore-aligned Justify Syndicate. The Greens bought Haffner's dam, Earth Strike, privately in Europe. Haffner, racing for a Coolmore partnership, took the Royal Lodge Stakes (G2) and is pre-entered as a Breeders' Cup Challenge Series: Win and You're In winner for the Breeders' Cup Juvenile Turf (G1T). Earth Strike has a full sister to Haffner at her side and is in foal to Nyquist .
D. J. Stable uses a diversified approach. It keeps some 23 broodmares, with about half at Taylor Made Farm and half with Bill Betz. It also uses a team of advisers, having started with the theories of noted bloodstock man Ken McLean. Contributing to decisions are Casse and fellow trainer Joe Orseno; Jeff Hayslett and Mark Taylor at Taylor Made; Betz; and Kim Valerio and Lauren Carlisle. The Greens make the final decision on matings, sending mares both to proven sires as well as first- or second-year commercial stallions.
D. J. Stable is also the breeder of 2025 Demoiselle Stakes (G2) winner Zany and stakes-placed 2-year-old Braums Run; and co-breeder of 2026 stakes winner Light Won Up, 2026 grade 2 winner Alpine Princess, and 2026 stakes winner Fanshell Beach.
The Greens own Voyager, a Justify filly who took the Natalma Stakes (G1T) in Canada on the turf at Woodbine, and Canada, a Medaglia d'Oro colt who won the Cup and Saucer Stakes at Woodbine and could challenge Haffner in the Juvenile Turf if he draws into the field. Casse trains both and told BloodHorse Oct. 21 that Voyager would start on the dirt in the Breeders' Cup Juvenile Fillies (G1) rather than the Breeders' Cup Juvenile Fillies Turf (G1T).
"It's been a really good year," Green said. "We have to thank all the advisers for having a hand in what's going on with the D. J. breeding program."
