Boldnesian was an American Thoroughbred

Thoroughbred

The Thoroughbred is a horse breed best known for its use in horse racing. Although the word thoroughbred is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed...

 racehorse

Horse racing

Horse racing is an equestrian sport that has a long history. Archaeological records indicate that horse racing occurred in ancient Babylon, Syria, and Egypt. Both chariot and mounted horse racing were events in the ancient Greek Olympics by 648 BC...

 best known in racing for winning the 1966 Santa Anita Derby

Santa Anita Derby

The Santa Anita Derby is an American Grade 1 thoroughbred horse race for three-year-olds run each April at Santa Anita Park in Arcadia, California and carries a purse of $1 million. Inaugurated in 1935, it is considered the most important West Coast stepping-stone to the Kentucky Derby...

 and as a sire

Sire

Sire may refer to:* Father, the counterpart of a dam, particularly in animal breeding. See also stallion* James W. Sire, author on worldviews* Sire Records, a record label* Sire Advertising, an advertising agency...

. Scheduled to run in the Kentucky Derby

Kentucky Derby

The Kentucky Derby is a Grade I stakes race for three-year-old Thoroughbred horses, held annually in Louisville, Kentucky, United States on the first Saturday in May, capping the two-week-long Kentucky Derby Festival. The race is one and a quarter mile at Churchill Downs. Colts and geldings carry...

, Boldnesian's racing career was cut short by an operation after bone chips

Osteochondritis

Osteochondritis is a painful type of osteochondrosis where the cartilage or bone in a joint is inflamed.It often refers to osteochondritis dissecans...

 were discovered following his win in the Santa Anita Derby. http://select.nytimes.com/gst/abstract.html?res=F60610FB35541A7493C1AB1788D85F428685F9

At stud

Stud (animal)

A stud animal is a registered animal retained for breeding. The terms for the male of a given animal species usually imply that the animal is entire—that is, not castrated—and therefore capable of siring offspring...

, Boldnesian notably sired Canadian Horse Racing Hall of Fame

Canadian Horse Racing Hall of Fame

The Canadian Horse Racing Hall of Fame was established in 1976 at the Woodbine Racetrack in Toronto, Ontario to honor those who have made a significant contribution to the sport of harness and thoroughbred horse racing in Canada....

 inductee Bold Ruckus and Bold Reasoning

Bold Reasoning

Bold Reasoning was an American thoroughbred racehorse foaled in Florida. He was out of the Hail To Reason mare Reason To Earn, by the Santa Anita Derby winner Boldnesian, a son of Bold Ruler....

 who in turn sired the 1977 U.S. Triple Crown

United States Triple Crown of Thoroughbred Racing

In the United States, the "Triple Crown" is usually the Triple Crown of Thoroughbred Racing, a series of three Thoroughbred horse races for three-year-old horses run in May and early June of each year consisting of the Kentucky Derby, Preakness Stakes, and Belmont Stakes.While Daily Racing Form...

 winner Seattle Slew

Seattle Slew

Seattle Slew was an American Thoroughbred race horse who won the United States Triple Crown of Thoroughbred Racing in 1977, the tenth of eleven horses to accomplish the feat. He remains the only horse to win the Triple Crown while undefeated. In the Blood-Horse magazine List of the Top 100 U.S...

. Boldnesian was discovered to have carried the large-heart gene. http://pqasb.pqarchiver.com/newsday/access/638213211.html?dids=638213211:638213211&FMT=ABS&FMTS=ABS:FT&type=current&date=May+18%2C+2004&author=PAUL+MORAN&pub=Newsday+(Combined+editions)&desc=SMARTY+JONES%2C+Heart+of+champion&pqatl=google