The Kentucky Derby is only a few weeks away and press coverage of each contender is already at full blast. During the next few weeks we will hear about every aspect of the training, health, eating habits, right down to the choice of shoes of each of the potential participants.

It is easy to get carried away by all the commentary and the hype and lose sight of the elements that are most important in sorting out the contenders from the pretenders.

Today, I want to discuss one of the factors that will receive much of the attention from both turf writers and fans -Pedigree.

How important is an individual horse’s pedigree in evaluating potential Derby success?

Ever since Leon Rasmussen wrote in the early 80s that “no Kentucky Derby winner since 1929 had a Dosage Index higher than 4.00” handicappers and journalist have analyzed the pedigrees of Derby contenders almost obsessively.

The Dosage Index classifies horse pedigrees by type and assigns a number that reflects the ability that a horse has to compete at a specific distance - the lower the number, the greater the aptitude to compete at classic distances.

The idea that a number derived from pedigree alone could single handedly eliminate almost half the field from contention in the Derby was simple and alluring. And it worked!

It worked, that is, until in 1991 when a horse by the name of Strike the Gold won the Derby despite the fact that his Dosage Index was 9.00. His win was followed by wins by Real Quiet, Charismatic and Giacomo all of whom had Dosages in the higher than 4.00. These results put an end to Dosage as a theory for predicting Derby winners.

However, the idea that pedigree can be used to somehow gain an edge in selecting Derby winners did not die with Dosage. The race is now on to find the next magic number, explanation, or gimmick that will give a handicapper an edge in predicting Derby success.
Pedigree, as a general matter, can only give us the probability that a particular horse will have certain characteristics. The law of genetics is random in selecting traits that will be handed down to through the generations.

Therefore, we often see horses that display very different characteristics from the ones we expect to see by looking at their pedigree. For instance, a sprinter type who is able to succeed in the classics (Smarty Jones) or a turf horse that really likes dirt racing (Cigar).
For me, although a hard-core Pedigree enthusiast, Pedigree is not very important in handicapping this race. I believe that the usefulness of Pedigree is inversely proportional to the amount of additional information available on a given horse.

Pedigree is most important when planning a mating because there is no information available on the prospective foal (except of course the physical characteristics of the parents which should be taken into account).

At the yearling sales, pedigree is still crucial but it loses some of its importance because we have plenty of information on the build, conformation and temperament of the foal in question.

Finally, by the time a horse is ready to run, pedigree may still shed some light on certain factors like the ability of a foal to mature early or her preference for a specific surface but as soon as the gates open the usefulness of pedigree as a predictor of success is diminished even further.

The only relevant use of bloodlines in this Derby may be to try to determine which of the horses that have been successful in Polytrack may actually take to the dirt surface of Churchill downs – a surface they have never tried. But even here other factors such as workouts prior to the race may be much more telling.

We have too much information on Derby entrants to focus on bloodlines. Looking at genetics to predict Derby success is like using a meat cleaver to perform a fine surgery, it’s blunt and unnecessary.