Using Dosage To Your Advantage
Is Dosage still a valuable handicapping tool for today's speed-laden
pedigrees?
By: Jason Romaniuk
Whether you are a horse owner, breeder, trainer or handicapper, understanding
dosage could mean the difference between success and failure. Dosage
is a word that is thrown around often in the racing world; pedigree
analysts discuss it very intricately, but racing fans often misunderstand
it. With the Queen’s Plate fast approaching, there is no better
time to get a handle on the mystery of dosage and to understand which
contenders are most likely to conquer the 1-1/4 mile classic.
Although originally researched and studied by Lt. Col. J. J. Vullier
and Dr. Franco Varola in the early 20th century, it was not until
about twenty years ago that dosage became widely accepted as an accurate
way to evaluate a Thoroughbred’s pedigree.
Let it be clear then, that dosage is entirely different from conventional
pedigree analysis. While the latter is based on a historical perspective
of ancestral performance, the former relies heavily on the dynamics
of inheritance.
Dosage is a mathematical analysis of a Thoroughbred pedigree based
upon the location of certain outstanding sires in its family. These
outstanding sires are given the title Chef-de-Race (Masters of the
Breed). Only the most influential stallions over the last century
are chosen to make up the list. To date, there are about 200 sires
that have been honoured with this title. These stallions are split
into five categories: Brilliant – Intermediate – Classic
– Solid – Professional.
Sires designated under the Brilliant category tend to pass an affinity
for shorter distances to their progeny, while on the other end of
the spectrum, sires under the Professional category pass on an abundance
of stamina, effective at longer distances.
Certain sires are versatile enough to be qualified under two categories.
Mr. Prospector, for example, is labeled as a “Brilliant/Classic”
Chef. His get have proven themselves at distances ranging from five
furlongs up to nine, and even ten furlongs.
Depending on the generation in which he appears, a sire contributes
a fixed number of points to the horse in question. The following shows
how points are awarded according to generations:
• 1st generation equals 16 points
• 2nd generation equals 8 points
• 3rd generation equals 4 points
• 4th generation equals 2 points
If a sire has been named a Chef in more than one category, his points
are split between the two equally.
Once a horse’s profile is calculated it will look something
like this:
B I C S P DI CD
Horse A 16 8 2 2 0 8.33 1.35
Horse B 6 4 4 8 10 0.60 - 0.37
In this example, Horse A has a dosage very slanted towards speed.
Most of the influence in his pedigree is in the Brilliant or Intermediate
variety. Judging by his numbers, Horse A is most likely to enjoy distances
ranging from five to seven furlongs.
On the other hand, Horse B has a dosage that favours stamina. His
pedigree is dotted with influences from the Solid and Professional
categories. Consequently, Horse B is most likely to favour distances
over one mile, and even up to two miles.
The column denoted as DI on the chart, stands for Dosage Index. The
DI is simply the ratio of speed points to stamina points. Everything
to the right of the middle is stamina, everything the left of the
middle is speed. The Classic category (middle) is divided equally
between the two.
For Horse A, 16 + 8 + 1 are the speed points. The total is 25 speed
points. On the right we would add 1 + 2 + 0, for a total of 3 points.
Now we divide speed points by stamina points: 25 divided by 3 equals
8.33. This means the horse has over eight times as much speed as stamina.
For Horse B, the same calculations would yield a dosage index of
0.60. This indicates the runner has about two thirds as much speed
as stamina.
The last column on the chart, labeled CD, stands for the Center of
Distribution . This number marks the balancing point of all of the
numbers in the profile. The best way to understand the Center of Distribution
is to picture the spectrum of distances as a see-saw. There are weights
placed unequally on the see-saw. The proper place of the pivot on
the see-saw is equal to the correct DI number. The number will range
from + 2.00 (Brilliant) to – 2.00 (Professional). The number
0.00 is termed as the perfect blend of speed and stamina.
The CD is calculated using this formula: [(Bril x 2) + Int] –
[Solid + (Prof x 2)]/ total points. While more complicated to figure
out, this number helps determine the exact distance that will be favourable
for the subject horse.
As for the Queen’s Plate, many contenders can be better understood
pedigree-wise if one takes into account a horse’s dosage. Because
of the ‘classic’ distance of the plate (1-1/4 miles) many
handicappers like to pay special attention to the dosage index of
a horse. The rule of thumb is that a horse should be able to handle
1-1/4 miles if it possesses a DI of under 4.00. A horse is said to
have a sprint/miler pedigree if the DI exceeds that coveted mark.
There are exceptions to every rule, of course, and there have been
a few horses in the past that have negotiated the distance successfully
with a DI of over 4.00. While they are few and far between, these
types of situations could happen more frequently in coming years.
It is not that the experts are wrong concerning the Chef-de-Race
categories, it is just the current shift in ‘fashionable pedigrees’
that is slowly eliminating stamina-oriented breeding.
Owners now desire a different kind of racehorse, one that is fast
and precocious…very precocious. Patience is not a virtue for
a lot of owners who want a quick return on their investment. They
run their horses early and often, because of their sprint-based pedigrees.
Many new owners in the game do not want to let a stamina-oriented
horse develop slowly on its own, working up to the longer distances.
Consequently, some very solid stamina-based sires are being ignored
in favour of sires with speed-laden pedigrees.
Horses with a DI over 4.00 are more common than ever, and the increase
in numbers brings more opportunities for horses to win at distances
further than their pedigrees suggest – opportunities resulting
from the attrition of stamina in thoroughbred pedigrees.
Republished with
permission from Canadian Thoroughbred
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