On Belmont Stakes Day 2010, the Wall Street Journal published a short but highly informative article by Michael Salfino titled “Did Belmont Stakes Peak with ‘Big Red’?” It presented a scatter plot of the times in miles per hour for every winner of the Belmont Stakes since the race was lengthened to 1-1/2 miles in 1926.

Between 1926 and 1973, there was a positive correlation between year and speed: as the years advanced from 1926, speed of the Belmont winner also tended to increase. The correlation ended with Secretariat’s record-setting win in 1973.

According to research by Dr. Mark Denny, a Professor of Marine Sciences and Biomechanics at Stanford University, the Thoroughbred breed’s speed has topped out for races of 1-1/4 to 1-1/2 miles. His paper (“Limits to running speed in dogs, horses, and humans”) estimates “a maximum possible thoroughbred speed just 0.52% faster than Secretariat’s average of 37.5 mph” in the Belmont.

Dr. Denny states that the Thoroughbred breed essentially has a “closed lineage” and DNA testing has revealed that 95% of all contemporary Thoroughbreds are descended from the foundation sire the Darley Arabian. Dr. Denny says that “this results in less genetic diversity, increasing the risk of debilitating ailments.” The situation is exacerbated by the declining pool of registered Thoroughbreds. Certainly, modern-day statistics from American racetracks on breakdowns and data on number of starts corroborate Dr. Denny’s conclusions about “debilitating ailments.”  

Professor Denny offers a possible solution to increasing Thoroughbred speed: “Selective breeding with a different equine stock could yield faster horses.” This course of action would be controversial but merits close consideration. However, I don’t see it being given serious thought, much less implementation, because of strong resistance from within the racing and breeding industry.

I would add to Dr. Denny’s observations that a very restrictive and uniform racing medication policy in the United States is absolutely necessary to improve the Thoroughbred breed, as it would favor sound stallions and mares and penalize the rest. Some of the popular stallions standing at stud today would not have been able to achieve what they did on the racetrack sans raceday medication and therefore would not be so important in propagating the breed. The view here is that enhanced soundness is far more important than incremental advancements in speed.

For the full text of the Wall Street Journal article and the aforementioned scatter plot, click here.

Copyright © 2010 Horse Racing Business