Making the Derby Field 2839

Like that Christmas tree that is buried in your attic only to be displayed once a year, so is the Dosage Index.  Forgotten about for most of the year until about the middle of March to the beginning of April, the Dosage Index resurfaces with the anticipation of the Run for the Roses.  There are many of those that believe that Dosage figures are nothing more than a compilation of numbers manipulated to come up with any result that you want.  This is due to the fact that the classifications and additions of a chefs-de-race can be changed from year to year.  Dosage purists like to boast the fact that of the sixty-five Kentucky Derby winners only five have ever had a DI (Dosage Index) of above 4.00. 

The Dosage for the previous seven Bluegrass Derby winners is as follows:

It is not my intention to debate this theory, but rather to help shed some light onto the subject of Dosage.

Dosage is a method for classifying Thoroughbred pedigrees by type.  It originated back in the early 20^th century from a study of the best thoroughbreds in England and France.  I t was discovered that a handful of stallions appeared with regular frequency in the top European runners.  This select group of premier stallions is distinguished by the term chefs-de-race. 

Dosage has evolved over the years as a statistical method for evaluating pedigree analysis.  Each chef is assigned to one or two of five aptitudinal groups (Brilliant, Intermediate, Classic, Solid, and Professional) covering the spectrum (from left to right) of speed to endurance.  These attributes were assigned to best reflect the traits these stallions passed on to their offspring.   

The Dosage Index (DI) is the ratio of inherited speed to stamina in the pedigree.  Dosage Profile is split down the middle through the Classic aptitudinal group. The numbers on the left side represent speed. Those on the right side represent stamina.

If you look at the Dosage Profile (pedigree query) of Danzig it would look something like this:

DP = 15 (Brilliant)-11 (Intermediate)-14 (Classic)-0 (Solid)-0 (Professional)

You can see that Danzig was bred from the center of the spectrum (Classic) back to the front of the Spectrum (Brilliant). 

The Dosage Index is determined by dividing the speed component (the Brilliant points plus the Intermediate points plus one-half the Classic points) by the stamina component (one-half the Classic points plus the Solid points plus the Professional points).

15(B) + 11(I) + 7(C) / 7(C) + 0(S) + 0(P)

33 / 7 = DI 4.71

The Dosage Index for Danzig is 4.71.

The Center of Distribution (CD) is a balance point of all weighted aptitudes supplied by chefs in the four generations. It represents the equidistance between the Classic and Intermediate aptitudes. To determine the Center of Distribution this formula is used:

(2xB + I – S – 2xP) / (B + I + C + S + P)

(2×15(B) + 11(I) – 0(S) – 2×0(P) / 15(B) + 11(I) + 14(C) + 0(S) + 0(P)

30 + 11 -0 -0 / 15 + 11 + 14 + 0 + 0

41 / 40 = 1.03

The Center of Distribution for Danzig is 1.03

The big question is what do all of these numbers mean? 

Dosage figures correlate with the average distance of the races in each category. The precision of the technique is highlighted in the table below where average Dosage figures are displayed for specific distances between 5.5 and 12 furlongs for open stakes between 1983 and 2004.

Reprinted from http://www.chef-de-race.com/

So if you were racing Danzig for the very first time and you took into consideration his Dosage Profile you might determine that with a DI 4.71 and a CD 1.03 that Danzig would be best suited in sprints.

It is apparent to me that many of the breeders in the Sim community pay very close attention to Dosage when breeding and placing their horses.  There are also those that subscribe to the theory of breeding the best to the best.  The one fact that remains unanimous amongst us all is that it takes a little ability and a whole lot of luck to breed a champion.