Kentucky Derby pedigree profile: Sun Thunder

April 19th, 2023

Fourth in the Southwest (G3). Second in the Risen Star (G2). Fifth in the Louisiana Derby (G2). Fourth in the Blue Grass (G1). By picking up Road to the Kentucky Derby qualifying points in a quartet of prep races, Sun Thunder earned his ticket to the 2023 Kentucky Derby (G1).

Should Sun Thunder visit the winner’s circle on the first Saturday in May, he’d be the third son of Into Mischief to win the Kentucky Derby. Though, presumably, he’d be the first to do so without extenuating circumstances.

Sun Thunder Pedigree
Harlan's Holiday
Into Mischief
Leslie's Lady
Sun Thunder
Medaglia d'Oro
Greenfield d'Oro

Into Mischief needs no introduction. He’s been North America’s leading stallion four years in a row. For many years he had a reputation for siring sprinters and milers like Breeders’ Cup Dirt Mile (G1) winners Life Is Good and Goldencents and Breeders’ Cup Filly & Mare Sprint (G1) heroines Gamine and Covfefe. That isn’t surprising since his progeny win at the modest average distance of 6.8 furlongs.

But Into Mischief is a half-sibling to four-time Eclipse Award winner Beholder and Breeders’ Cup Juvenile Turf (G1) winner Mendelssohn, two elite racehorses who did their best work running long. And Into Mischief proved he’s more than a speed sire when his sons Authentic and Mandaloun won back-to-back Kentucky Derbys in 2020 and 2021.

It should be noted that Authentic won an unusual Kentucky Derby delayed until September due to COVID-19, and Mandaloun earned his victory via the disqualification of Medina Spirit due to a positive drug test. But Authentic reiterated his 1 1/4-mile prowess with a triumph against older horses in the Breeders’ Cup Classic (G1), and Into Mischief is also the sire of 2018 Kentucky Derby third-place finisher Audible, so the takeaway is clear: Into Mischief is capable of siring elite classic types, even if they come along less often than his sprinters and milers.

Meanwhile, the bottom half of Sun Thunder’s pedigree contains an interesting mixture of speed and stamina. His dam is Greenfield d’Oro, a daughter of Medaglia d’Oro out of the Elusive Quality mare Maryfield.

Greenfield d’Oro failed to win in two starts, but she lost her jockey in one and finished second in the other, so she had very little opportunity to showcase her talent. In contrast, Medaglia d’Oro and Maryfield were elite runners from opposite ends of the distance spectrum.

Medaglia d’Oro was all about stamina; he won the Travers (G1) over 1 1/4 miles, ran second in the Belmont (G1) over 1 1/2 miles, and finished second in the Dubai World Cup (G1), Pacific Classic (G1), and two editions of the Breeders’ Cup Classic racing 1 1/4 miles. At stud, he’s sired Horse of the Year Rachel Alexandra, Hong Kong superstar Golden Sixty, Breeders’ Cup Turf (G1) winner Talismanic, two-time champion Songbird, and Grade 1 winners Elate, Marketing Mix, New Money Honey, and Higher Power, all elite winners racing 1 3/16 miles or farther. All told, Medaglia d’Oro’s progeny have won at a lofty average distance of 7.7 furlongs.

Maryfield, on the other hand, was voted 2007 champion female sprinter after posting victories in the Breeders’ Cup Filly & Mare Sprint and Ballerina (G1). That isn’t surprising when you consider how her sire, Elusive Quality, was a talented sprinter/miler who won the one-mile Poker H. (G3) over the Belmont Park grass in the world-record time of 1:31.63. But it should be noted Elusive Quality wasn’t exclusively a source of speed at stud; he passed on enough stamina to sire Kentucky Derby and Preakness (G1) winner Smarty Jones and Breeders’ Cup Classic winner Raven’s Pass.

A mixture of speed and stamina is often the secret to success in the Kentucky Derby, and the cross of Into Mischief and Medaglia d’Oro should prove suitable to carry Sun Thunder over the Derby distance of 1 1/4 miles on dirt.

Further Analysis on Sun Thunder