**Dosage: Pedigree &
Performance**

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**A Brief Review of DOSAGE: A
PRACTICAL APPROACH**

Dosage, a technique for classifying
Thoroughbred pedigrees by type, originated in the early part of the 20th century
from the research of the Frenchman Lt. Col. J. J. Vuillier. In his classic study
of the extended pedigrees of the best runners in England and France, Vuillier
(in LES CROISEMENTS RATIONNELS DANS LA RACE PURE) observed that very few
stallions appeared with any great frequency. He called these stallions *
chefs-de-race*. He also noted that the degree of inheritance attributed to
these *chefs-de-race* was essentially constant in all pedigrees, the absolute value
(or Dosage figure) varying from sire to sire. Furthermore, he demonstrated that
in successive 15 to 20 year time frames, new series of *chefs-de-race*
emerged which eventually established their own fixed degree of influence. This
process, in which new series of *chefs-de-race* periodically become dominant,
provides a rational model for the evolution of the Thoroughbred race horse.
Vuillier believed that the objective in breeding should be to attain Dosage
figures in the foal as close as possible to the established Dosage figures for
the breed. For some time he practiced his theories successfully in the employ of
H. H. The Aga Khan, breeder of such notables as Bahram, Majideh, Mahmoud, and
Nasrullah, among many others.

Some years later, the Italian Dr. Franco Varola (in TYPOLOGY OF THE RACE HORSE
and THE FUNCTIONAL DEVELOPMENT OF THE THOROUGHBRED) developed a modified version
of Dosage that retained the principle that Thoroughbred evolution proceeds
through the influence of a very small number of the stallions at stud in any
era. Varola did, however, shift the emphasis from quantity (i.e., the degree of
inheritance associated with individual sires) to quality (i.e., the pattern of
aptitudinal traits inherited from key ancestors). Discounting the generation in
which his expanded list of *chefs-de-race* appeared, he arrived at a distribution
of aptitudinal traits in a given pedigree that described the "type" of the horse
being analyzed. The most significant point made by Varola was that the
characteristics transmitted by his *chefs-de-race* were not necessarily those they
possessed as runners. The focus, instead, was entirely on the qualities passed
on as breeding animals. Thus, in contrast to conventional pedigree analysis
based on an historical perspective of ancestral performance, Dosage relies on
the dynamics of inheritance. As an alternative and complementary method of
pedigree interpretation, it may help avoid potential problems associated with
the traditional concept of "breeding the best to the best".

Our approach, which first appeared publicly as
a series of articles in Leon Rasmussen's Bloodlines column in Daily Racing
Form just prior to the 1981 Kentucky Derby, has been to fuse the basic ideas of
Vuillier and Varola, incorporating both quantitative and qualitative components
in the hope of providing additional insights. In order to establish greater
utility, we chose to use more accessible four-generation pedigrees instead of
the extended pedigrees used previously. We also re-introduced Vuillier's
approximation of a genetic effect by halving the influence of any *chef-de-race* in
each successive earlier generation. Finally, we established a statistical method
for evaluating the results of our analysis. In this framework, Dosage in its
latest configuration was developed.

Each *chef-de-race *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. The
assignments are made to best reflect the traits that these stallions predictably
and consistently transmit to their offspring. For bookkeeping purposes we assign
a total potential value of 16 points to each generation. Since there are,
progressively, one, two, four, and eight sires in the first four generations, *
chefs-de-race* that appear among these sires will contribute 16, 8, 4, and 2 points
each as we work back. The points for all *chefs-de-race* present are then tallied
in the appropriate aptitude columns. *Chefs-de-race* that confer two aptitudinal
characteristics have their points split between the two aptitudes. In the end,
the total points in each column produce the **Dosage Profile (DP)**, a series of five
numbers that reflect the relative proportions of each of the five aptitudes and
is expressed in the order:

**Brilliant-Intermediate-Classic-Solid-Professional**

For example, the DP of the leading
classic sire Halo, dk.b. or br. c., 1969 (Hail to Reason-Cosmah, by Cosmic
Bomb), himself a *chef-de-race*, is calculated as follows:

GENERATION (PTS) | SIRES (APTITUDINAL GROUP(S)) | B | I | C | S | P | |

1ST GENERATION (16): | HAIL TO REASON (CLASSIC) | 16 | |||||

2ND GENERATION (8): | TURN-TO (BRILLIANT/INTERMEDIATE) | 4 | 4 | ||||

COSMIC BOMB (N/A) | |||||||

3RD GENERATION (4): | ROYAL CHARGER (BRILLIANT) | 4 | |||||

BLUE SWORDS (N/A) | |||||||

PHARAMOND II (N/A) | |||||||

MAHMOUD (INTERMEDIATE/CLASSIC) | 2 | 2 | |||||

4TH GENERATION (2): | NEARCO (BRILLIANT/CLASSIC) | 1 | 1 | ||||

ADMIRAL DRAKE (PROFESSIONAL) | 2 | ||||||

BLUE LARKSPUR (CLASSIC) | 2 | ||||||

SIR GALLAHAD III (CLASSIC) | 2 | ||||||

PHALARIS (BRILLIANT) | 2 | ||||||

BLUE LARKSPUR (CLASSIC) | 2 | ||||||

BLENHEIM II (CLASSIC /SOLID) | 1 | 1 | |||||

PEACE CHANCE (N/A) | |||||||

DP: |
11 |
6 |
26 |
1 |
2 |

The ratio
of points in the speed
wing (Brilliant points + Intermediate points + one-half the Classic points) to
points in the stamina wing (one-half the Classic points + Solid points +
Professional points) is the **Dosage Index (DI)**. This number is directly proportional
to the inherited prepotent speed in a pedigree and inversely proportional to the
stamina. A DI of 1.00 indicates a balance of the two. The DI of Halo is 1.88
((11 + 6 + 13) divided by (13 + 1 + 2)).

If we consider the five aptitude groups as points
spaced equally along a linear scale where Brilliant is assigned a value of
+2.00, Intermediate is +1.00, Classic is 0.00, Solid is -1.00, and Professional
is -2.00, the DP allows for the calculation of the **Center of Distribution
(CD)**, that
point along the scale corresponding to the total combined influences of all *
chefs-de-race* in the pedigree. In that sense, it is a balance point (analogous to a
center of gravity) of all weighted aptitudes supplied by *chefs-de-race*
in the four generations. Calculation of the CD is done by taking the sum of
twice the Brilliant points plus Intermediate points minus Solid points minus
twice the Professional points and dividing that number by the total points in
the DP. An exact balance of speed and stamina yields a CD of 0.00. The CD for
Halo is 0.50 (((2 x 11) + 6 - 1 - (2 x 2)) divided by (11 + 6 + 26 + 1 + 2)),
which places the combined effect of all *chefs-de-race* in his four generation
pedigree equidistant between the Classic and Intermediate aptitudes.

For reference, a current list of *chefs-de-race*
is located at this site*. *The *chefs-de-race* are shown in alphabetical
order along with their aptitudinal assignments where B=Brilliant,
I=Intermediate, C=Classic, S=Solid, and P=Professional.

Research using the described methodology as a tool for pedigree classification has resulted in many revealing observations including the following:

1. There is a direct correlation between the DI or CD and performance at varying distances as determined from separate populations of stakes winning sprinters, middle distance runners, and routers. As expected, the sprinters have the highest values (reflecting the importance of speed in short races), the routers have the lowest (confirming the need for endurance in long races), and the middle distance runners fall in between. In general, the 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 2011. The correlation is virtually linear, confirming the direct relationship between distance and the speed/stamina characteristics of pedigrees as expressed by Dosage figures.

DISTANCE | AVG DI | AVG CD | ||

5 1/2 f | 4.02 | 0.81 | ||

6 f | 4.26 | 0.87 | ||

6 1/2 f | 3.75 | 0.82 | ||

7 f | 3.73 | 0.82 | ||

8 f | 2.98 | 0.68 | ||

8f & 70 yds | 3.29 | 0.73 | ||

8 1/2 f | 3.05 | 0.69 | ||

9 f | 2.86 | 0.65 | ||

9 1/2 f | 2.52 | 0.57 | ||

10 f | 2.50 | 0.56 | ||

11 f | 2.10 | 0.47 | ||

12 f | 2.02 | 0.43 |

2. Elite Thoroughbreds as a group (e.g., champions, classic winners, leading
sires) have significantly lower DIs and CDs than the general population of
stakes winners, suggesting that outstanding performance on the track or at stud
benefits from a large component of inherited stamina. There is no evidence,
however, of an inherent superiority associated with lower Dosage figures. In
other words, a lower DI is not better than a higher DI. Rather, the lower Dosage
figures merely reflect the fact that our most prestigious races are run at
longer distances and that successful competitors are aptitudinally suited to
those races. Elite Thoroughbreds also have a higher point total in their DP than
do typical stakes winners, acknowledging the fact that they tend to be somewhat
better bred, at least to the extent that more *chefs-de-race*
in a pedigree correlate with superior breeding stock.

3. Five winners of the Kentucky Derby since 1940 (Strike the Gold, Real Quiet, Charismatic, Giacomo and Mine That Bird), and five winners of the Belmont Stakes over the same time frame (Damascus, Conquistador Cielo, Creme Fraiche, Commendable and Sarava) have had a DI above 4.00. This is in direct contrast to dirt stakes winners in general, of which about one-fourth have a DI greater than 4.00 and for which the average DI is about 3.6. The combination of Dosage and our observation that 23 winners of the Kentucky Derby since 1972 were ranked as a juvenile within 10 pounds of the high weight on the Experimental Free Handicap or were named juvenile champion in another country has become an especially powerful tool in isolating the true classic contenders. In the seven Derbies where a "dual qualifier" (i.e., DI and two-year-old form) failed to win, three finished second, and in four of those races, a qualifier subsequently won either the Preakness or Belmont Stakes. The implications of this result are that a pedigree suited to distance, along with a demonstration of high-class, early maturity are more important for classic performance than other factors such as form in the pre-Derby preps at distances less than ten furlongs. Over the past three decades, an average of only three and a half starters per Derby have met both criteria, including longshot winners Genuine Risk, Gato del Sol, Ferdinand, Alysheba, Unbridled, Sea Hero, Go for Gin, and Thunder Gulch. In addition, the "dual qualifiers" have accounted for 9 exactas and 5 trifectas. Thirty-three percent of all "dual qualifiers" won at least one classic race.

4. The average DI of juvenile stakes winners steadily decreases throughout the season, indicating a larger speed component in the pedigree of winners early in the year relative to winners later on. This phenomenon parallels the need for greater stamina as the distances of races for two-year-olds increase through the year.

5. The DI of many steeplechase champions since 1972 exceeds the classic guideline figure of 4.00 despite the long distances associated with steeplechase racing. This result suggests that the pace of these races is well within the ability of speed-bred runners and that their quickness over the jumps can be a more important factor for success. The remainder of steeplechase champions have had a DI close to 1.00 or less, more typical of expectations for competitors at very long distances. Surprisingly, there are few steeplechase champions with a DI in the range of middle distance flat racers.

6. The average DI of stakes winners at tracks favoring speed is higher than the average DI of stakes winners at tracks where speed is less favored. This result is consistent with the observation that brilliantly bred runners often carry their speed further on the speed-oriented surface.

7. Turf stakes winners have, on average, a lower DI than stakes winners on dirt.
Furthermore, the turf runners have a significantly greater representation of
Solid and Professional *chefs-de-race* in their pedigree. This result is consistent
with the observation that turf races are run at a longer average distance than
are races on dirt.

The studies described here are based on large populations that reflect
statistically significant trends. The Dosage user must recognize, however, that
within these populations there is great variation. Accordingly, Dosage figures
for an individual may not conform to those of the whole population. Greater
accuracy and increased predictability depends in large part on a continual
modification and refinement of the *chef-de-race* list, guided by the
principle of a better description of reality.