An exemplary talent both on the racetrack and in the breeding shed, the Thoroughbred industry suffered a great loss Dec. 19 when it was announced that Coolmore's Ashford Stud stallion Uncle Mo was euthanized following an injury to his left foreleg. He was 16.
"We're all still in shock," said Coolmore America manager Dermot Ryan. "He will be greatly missed by everyone here, in particular by his personal groom Rene Macias. He was an exceptional sire both on the racetrack and in the sales ring."
Mike Repole, who owned Uncle Mo throughout his racing career and stayed in on him at stud, stated in a post on X that the stallion had surgery Dec. 18 and that the recovery process was "too much for him to endure." Ryan thanked both Hagyard Equine Medical Institute veterinarians Dr. Barry David, Dr. Bob Hunt, and Dr. Cole Sandow for their work in trying save Uncle Mo, as well as the Ashford team for the care they gave him over the years.
"The Repole Stable family, Todd Pletcher family and the entire Coolmore family are heartbroken," Repole said. "Uncle Mo was so much more to me than a champion and iconic stallion—he was and always will be part of my family."
Bred in Kentucky by D. Michael Cavey, the son of Indian Charlie out of the stakes-placed winning Arch mare Playa Maya made two appearances in the Keeneland sales ring, first selling from the Denali Stud consignment to Moon Bloodstock for $160,000 as a weanling in the 2008 November Breeding Stock Sale. Ten months later he returned to Keeneland for the September Yearling Sale consigned by Four Star Sales and was purchased by Mike Repole of Repole Stables for $220,000.
Sent to the barn of trainer Todd Pletcher and ridden by John Velazquez, both now Hall of Famers, Uncle Mo drew immediate attention with an eye-catching 14 1/4-length domination on debut at Saratoga Race Course. The colt quickly became a grade 1 winner in his second start, again winning with ease by 4 3/4 lengths in the 2010 Champagne Stakes (G1) at Belmont Park.
He wrapped up honors as 2010's Eclipse champion 2-year-old male at Churchill Downs on racing's biggest stage, submitting one of the most commanding, dominating and, as track announcer Trevor Denman described it, overwhelming performances in Breeders' Cup Juvenile (G1) history, winning by 4 1/4 lengths.
At 3, Uncle Mo returned with another scintillating 3 3/4-length score in the Timely Writer Stakes at Gulfstream Park before suffering his first defeat when third in the Wood Memorial Stakes (G1). Despite that loss, Uncle Mo still entered the 2011 Kentucky Derby (G1) as one of the leading favorites. However, an illness led to him being scratched on Derby morning.
Uncle Mo resurfaced three months later in the King's Bishop Stakes (G1), settling for second when caught by a nose on the wire by eventual 2011 Breeders' Cup Dirt Mile (G1) winner Caleb's Posse . His second start off the layoff showed flashes of his previous brilliance again, winning the Kelso Handicap (G2) at Belmont Park by three lengths in a sharp 1:33.82 over a sealed muddy track.
Uncle Mo was retired with $1,606,000 in purse earnings at the end of his 3-year-old season after a disappointing 10th in the Breeders' Cup Classic (G1) and began his successful stallion career at Coolmore's Ashford Stud.
"Will never forget running into Todd just before the Derby draw and him telling me Uncle Mo might be a scratch," trainer Graham Motion, who won the 2011 Derby with Animal Kingdom, recalled on X Thursday. "The rest is history, who knows how good a racehorse he might have been. We all know what a brilliant sire he has been. Huge loss."
Through Dec. 18, Uncle Mo has sired 887 winners from 1,320 starters with progeny earning more than $124 million on the track. The fastest predominantly dirt sire to reach 100 stakes winners, Uncle Mo has sired 109 stakes winners, including 15 grade 1 winners, 16 grade 2 winners, and 25 grade 3 winners. He finished as the leading freshman sire of 2015 behind a then-record $3,670,354 in progeny earnings (since surpassed by Gun Runner ). Uncle Mo would finish as the leading second-crop sire in 2016 when he finished among the leading sires overall for the first of four times, to date: 2016, 2020, 2022 and 2023.
Just as he enjoyed a fast start on the track, Uncle Mo's stallion career got off to a quick start with his first North American crop producing 25 individual black-type winners, 14 graded. That first crop included five-time grade 1 winner, 2015 Breeders' Cup Juvenile winner, Eclipse champion 2-year-old male, and 2016 Kentucky Derby winner Nyquist , who retired with earnings of more than $5.1 million.
Following Nyquist's success, Uncle Mo's stud fee was elevated to $150,000 for the 2017 season and never fell below $125,000 the rest of his career. He was advertised at a $125,000 stud fee for the 2025 season before his death.
Uncle Mo was represented by his second classic winner in 2022 when Mo Donegal , who was also owned by Repole in partnership with Donegal Racing, won the Belmont Stakes (G1). Uncle Mo was also the sire of two-time Breeders' Cup winner Golden Pal , who took home the Breeders' Cup Juvenile Turf Sprint (G2T) in 2020 and the Breeders' Cup Turf Sprint (G1T) in 2021.
Other grade 1 winners sired by Uncle Mo include A Mo Reay, Adare Manor, Arabian Knight , Bast, Dream Tree, Gomo, Kingsbarns , Mo Forza , Mo Town , Outwork, Unbridled Mo, and Yaupon .
As an emerging broodmare sire, Uncle Mo is the sire of 320 dams of 641 named foals of racing age. Out of 411 runners, 242 are winners. He is the sire of Sataves, the dam of 2024 Horse of the Year candidate Thorpedo Anna.
PORTER: Uncle Mo Makes Headlines as Emerging Broodmare Sire
"I would like to thank Mike Repole for giving us the opportunity to stand him in the first instance and for being a truly fantastic partner," Ryan said. "Todd Pletcher for training to perfection, the Coolmore partners for placing such faith in him and our loyal clients for their unwavering support."
"Uncle Mo is the patriarch of Repole Stable. There will never be another horse that makes me feel or will impact my life the way that Uncle Mo has," Repole said. "Thank you Uncle Mo for fulfilling my childhood dreams of owning a special racehorse."
