What is dosage?

Dosage is a powerful tool to analyse thoroughbred racehorses.

At the very least it provides a mathematical estimate of the distance at which a horse is likely to perform at its best, however many pundits believe it can also predict a horse’s stakeswinning potential.

A practical example is the question that often arises at Cup time; will a certain horse stay two miles? The answer can be found in its dosage profile.

Over the past 4 or 5 decades, dosage analysis suggests that a Melbourne Cup winner should have a dosage index in the range of 1-2, which places it in the stayers category. Cup winners with dosages in excess of 4 are very rare indeed, however they are commonplace in the sprinting ranks. Dosage is often used in this way as an additional aid to raceform analysis.

Another example of how dosage can help, is the finding that stakeswinners with dosages greater than 5 are extremely rare. With this knowledge, would you go ahead with a mating that produces a dosage rating of more than 5 in the resultant foal? You can see the immense value of dosage, both to punters and breeders alike.

Dosage has been around for almost 100 years, and has been used by many people throughout the world to gain insight into thoroughbred racing prowess. It is a mathematical analysis of the strengths in a thoroughbred pedigree, based upon the location of certain outstanding sires in the family. These preeminent sires are known as “Chefs” and are listed on the Chef-de-Race web site.

Chef-de-Race stallions have been assigned to the following categories: Brilliant (B) - Intermediate (I) - Classic (C) - Solid (S) - Professional (P). These five categories represent the full range from speed (Brilliant) to stamina (Professional). To add more enlightenment, some stallions are classified into two categories, such as Brilliant/Intermediate or Classic/Professional, with perhaps more categories in the wings.

A-NZ Keysires

Unfortunately, for us in the Southern hemisphere, the Chefs list takes no account of influential sires in Australia and New Zealand and there are some examples where the ratings placed on our horses are based solely on progeny on Northern American circuits, far removed from our own race conditions.

Hence, an internationally-renowned exponent of dosage theory, John Hutchinson, felt it was time to adapt dosage analysis to our locally-bred stock. He single-handedly set upon the task of analysing more than 150 Australian and New Zealand (A/NZ) sires, and the result of this seminal work is the ANZ Keysires list. Today, this list is incorporated into pedigree analysis software tools as the quintessential guide to dosages of colonial-bred racehorses.

The ANZ Keysires list is published on the Dosage.com.au web site.

Dosage web resources

Aside from Dosage.com.au, there are a number of useful web sites that provide an explanation of the numbers, and how they are derived, so please refer to them for details. Links to these sites are provided at the bottom of this page.

John Hutchinson’s “Dosage News” page on Thoroughbred Village provides an excellent introduction to dosage in this part of the world, and is required reading for all potential students of this discipline.

Other important information on ANZ dosage can be found online at the links below.

Dosage News: Great introduction to dosage from the regional expert.
Progold Thoroughbreds: Dosage analysis and mating plans.
Take 2's web site: Historical analysis of dosage patterns.
Jack's Chatter: New Zealand perspective.

Important international sites in this field are:

Chef-de-Race: The definitive international dosage site.
Thoroughbred Champions: Great tutorial and links.

How do I request a horse's dosage profile?

The Dosage Search facilities on Dosage.com.au help with the profiling of notable thoroughbreds. Many of the most popular Australasian-bred horses are listed with their dosage profile and distance aptitude. If your favourite horse is not there, it’s easy to request an analysis, and it’s a free service to the Dosage.com.au community.

In summary, if it’s about dosage in Australia and New Zealand, you'll find it at Dosage.com.au!