Almost since the beginning of time, man has been fascinated by artificial selection — the idea that through careful manipulation of the breeding process, one can achieve a more desirable result, whether that be a better-tasting broccoli, a fatter cow or a seedless watermelon.
In On the Origin of Species, first published in 1859, Charles Darwin wrote: “Slow though the process of selection may be, if feeble man can do much by his powers of artificial selection, I can see no limit to the amount of change to the beauty and infinite complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may be effected in the long course of time by nature’s power of selection.”
But the verbose Darwin wasn’t the only one who believed in the power of artificial selection, or selective breeding.
Sir Frances Galton coined the term “eugenics” (the use of selective breeding to improve the human condition) and his book, Hereditary Genius (1869), was the first to examine superior intelligence and greatness from a scientific standpoint. Heck, even Plato was fond of artificial selection, arguing — in 400 BC, mind you — for state-sponsored breeding programs designed to produce better, smarter people.
Obviously, Plato’s dream was never realized, as a quick perusal of social media on any given day will attest to — and I would argue that artificial selection has also been woefully ineffective in producing better thoroughbred racehorses.
When one considers that the very intent of thoroughbred horse racing is to improve and showcase the breed (geldings were excluded from competing in the Belmont Stakes from 1919 to 1957 for this very reason), the lack of progress is stunning.
For example, the median winning time of the Kentucky Derby from 2010-present is 1 1/5 seconds slower than it was from 1950-59, while the median winning time of the Belmont Stakes from 2010-present is 1 second slower than it was in the 1950s.
And this slowdown is occurring despite the fact that the number of registered thoroughbreds being born each year, while rapidly declining, is still more than double what it was in the ‘50s.
* Partially based on estimates.
The lack of improvement in thoroughbred race times in the Kentucky Derby and Belmont Stakes becomes even more apparent when compared to the times of human runners.
In an article entitled “Why horses in the Kentucky Derby aren’t getting faster—but humans are,” author Oliver Staley notes that “the Derby record of 1:59.4 for a mile and a quarter was set by the legendary Secretariat in 1973, and only once since then, in 2001 by Monarchos, has the winner finished under two minutes.”
“Meanwhile, human runners keep getting faster. The world record in the men’s 800 meters — which is around half a mile and historically takes roughly the same amount of time to complete — has fallen three seconds in the same time period,” Staley writes
Granted, track conditions have a much greater impact on times in horse racing than they do in races for humans, but it should also be pointed out that world records in track and field require that more stringent conditions be met. For example, if a tailwind exceeds two meters per second (about 4 ½ miles per hour), the time will not be recognized as a record at any level of competition, except, perhaps, a grade school field day.
Some, like Professor Mark W. Denny of Stanford University, believe that thoroughbreds aren’t getting faster due to biology. There is a limit to how fast any animal can run and, largely thanks to selective breeding, horses have simply reached that limit sooner than humans have.
Others disagree. In fact, a recent University of Exeter study claimed that, at least in England, on the turf, horses “have been getting faster by an average of 0.013 yards (0.4 inches) per second each year [over six furlongs].”
“There has been a general consensus over the last 30 years that horse speeds appeared to be stagnating,” Patrick Sharman, a doctoral student from the Centre for Ecology and Conservation at the University of Exeter’s Penryn Campus in Cornwall told The Telegraph.
“Our study shows that this is not the case and, by using a much larger dataset than previously analyzed, we have revealed that horses have been getting faster.
“Interestingly, both the historical and current rate of improvement is greatest over sprint distances. The challenge now is to find out whether this pattern of improvement has a genetic basis,” Sharman concluded.
Of course, the finding that the greatest rate of improvement (if we accept that horses are improving at all) is coming in sprint races should come as no surprise. With more and more emphasis on flashy times recorded in two-furlong drills designed to attract yearling sale buyers, it is hardly earth-shattering that stamina has become a rare commodity in US racing.
Since 1940, the average winning late speed ration (LSR) in the Kentucky Derby and Belmont Stakes has dropped (gotten slower) by nearly two lengths.
Meanwhile the average Dosage Index — designed to determine the distance potential of horses based on hereditary factors (the higher the DI, the less stamina a horse is purported to have) — of Kentucky Derby and Belmont Stakes winners has steadily increased over this same time period.
“The increasing number of Derby winners with non-Classic Dosage figures was predicted over 30 years ago when the observed trend from 1940 onward suggested that, unless breeding patterns changed, half of all Derby winners would exceed the DI 4.00 guideline figure in the 2020 to 2040 time-frame,” said Dr. Steven Roman, creator of the Dosage concept.
“This appears to be what is happening, although no one paid attention at the time because they didn’t understand that Dosage is dynamic rather than static and only reflects the breeding culture at a particular point in time.”
So, all those who think that a horse can’t “get the distance” of the Belmont Stakes, might want to think again.
These days, it doesn’t take much.