CHANGE IN “SELECTIVE CONDITIONS”
century, the mantra of breeders has been “breed the best to the best and hope for the best.” The winners of prestigious, high-dollar purses are almost always retired to stud, where they attract mares who have themselves been winners or are dams or sisters of winners. In my previous EQUUS articles on the breed, which ran in 2014 and early 2015, I followed significant changes in the Thoroughbred industry through its 350-year history. The performance test that King Charles II designed in the 17th century---the racing conditions that defined the Thoroughbred and made it the world’s greatest equine athlete---originally put far more emphasis upon stamina (“stayer” capability or “bottom”) than upon speed. Nonetheless, in Europe beginning in the latter quarter of the 18th century and in America about 50 years later, long-distance heat racing began to go out of fashion. The test that the horses faced no longer consisted of four-mile courses, which they were originally required to run sometimes up to four times in a single day. The horses who ran the long courses had, of necessity, been allowed time to achieve physical maturity; it was rare in older times to see a horse at the flat track less than 5 years old, but at the same time common to find champions who began their careers at age 6 or 7 competing successfully well up into their teens.
Everything changed when futurity racing came into vogue. By definition, a “futurity” is a race open only to physically immature horses---2-, 3- or 4-yearolds. The Kentucky Derby is probably the world’s most famous futurity contest, although being American, it is not the oldest; that honor goes to races such as the British St. Leger Stakes, inaugurated in 1776. A race of two miles---half the distance that had been mandated
for heat-racers---was originally considered short enough to be a suitable and humane test for young horses. However, that distance was soon shortened even further, in part because of injuries, but also to create a more exciting race that could be run closer to the grandstand. By the time of Sir Barton’s 1919 Triple Crown victory, the concept of “classic” distance had become firmly fixed as between 1 and 1 ½ miles.
Biologists speak of this kind of alteration of the rules as a “change in selective conditions.” The biology term “selection” implies a winner---in nature,
The chart above shows the 26 sires referenced in the seven-generation pedigrees of Triple Crown winners from 1919 to 2015. Pink tones show the major branches of the Eclipse family, with Matchem shown in orange and Herod in yellow. At right is a chart...