Dosages are used throughout Europe and the USA in a variety of ways in breeding, training and selection of thoroughbreds.  To date, their application has been rarely used in Australia.  But can these well established practices give a new direction for Australian breeding?

History

In the early part of the 20^th century, the distinguished French student Lt Col JJ Vuillier extensively researched the pedigrees of numerous thoroughbreds.  Among many of his findings were some factors that continue to be effective today.  One of his major findings was that a limited number of stallions were present in the majority of pedigrees.  He called these stallions that were to shape the breed, “chefs-de-race.”  Translated into English “chefs-de-race” would be heads or leaders of the thoroughbred, and in today’s terms these are the likes of Star Kingdom, Danehill and Northern Dancer to name a few.  He also found that new chefs appeared with regular frequency throughout the history of the thoroughbred, and his studies represent an evolutionary model of the thoroughbred. 

The Italian, Franco Varola incorporated the dosage principles of Vuillier’s work resulting in his most famous work, “Typology of the Racehorse.”  While utilizing these principles, Varola’s work took the studies of dosage to a new level.  His work centered on moving the emphasis on the frequency that these horses appeared in pedigrees, to the quality of attributes contributed to their offspring. It is important to understand that these factors need not reflect the stallion’s own racetrack performance but rather they represent the aptitude of the progeny.  As the title of his work suggested, Varola was very much focused on the “type’ of racehorse being bred which he believed resulted from the pattern of aptitudinal traits inherited from key ancestors.

Dr Steven Roman, a US academic, further expanded the notion of dosages in his ground breaking work during the 1980’s.  His work largely combined both the qualitative and quantitative approaches of both Vuillier and Varola.  Dr Roman established a statistical method for evaluating dosage analysis.  He termed this the Dosage Index that is determined through a mathematical formula and central to our modern interpretation of the study.

The fundamentals

The principles of Dosage analysis however are founded on the basis that each of these chefs contributed a predictable characteristic to each of his progeny. 

These characteristics have been classified into 5 major categories (Brilliant, Intermediate, Classic, Solid and Professional) that cover the range from speed to stamina.  There is however some overlap in their practical application, as certain stallions may contribute in two aptitudinal groups.  The assignments are made to most accurately reflect the traits a stallion most consistently and predictably transmit to his progeny.  A key feature of these principles is that a champion thoroughbred will have a balance of these characteristics within their pedigree.

The great shift in dosages occurred through the work of the Italian, Franco Varola, which is outlined in his great work, Typology of the Racehorse.  Varola’s work extended the concept of the chef-de-race.  While Vuillier identified these prepotent sources within the breed, Varola identified that each chef instilled certain predictable and consistent characteristics into their progeny.

He classified the five major aptitudinal traits in:

Brilliant - Intermediate - Classic - Solid - Professional

Reading from left to right, these traits cover the spectrum from speed to stamina.  Varola also related much of his work to the type of the horse.  His studies also focused on inheritable traits such as colour and fast-twitch muscle for example, although these studies have now become the focus of geneticists, rather than proponents of dosages.

Throughout this website, and in fact most of the works that I publish, I will show a dosage profile in a particular format.  Let us use the example of Kingston Town, one of Australia's greatest ever horses.

His profile is expressed as

[0.55/1.86] [18-2-12-0-8]

or

[CD/DI] [Brilliant - Intermediate - Classic - Solid - Professional}

CD is Centre of Distribution

DI is Dosage Index

The US mathematician, Dr Steven Roman developed a mathematical formula to measure dosages during the 1980’s.  The two formulas are called a Center of Distribution [CD] and a Dosage Index [DI].  Both figures are largely a measurement of the relationship between speed and stamina in a pedigree and Dr Roman’s work concerned primarily the distance aptitude of a racehorse.