Dosage in Plain English

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Let’s say this, right now — in this context, dosage has no connection to doping horses. None. Nada. Zip.

If you follow horse-racing to any extent, you’ve heard the term and wondered what it meant. Maybe an explanation made your eyes glaze over. After all, you don’t need to know all the ins-and-outs.

So, this post is just a newbie’s introduction. And, if you stay long enough to read the entire post, you’ll find a little secret at the end that blew me away when I first read it.

Dosage is a statistical tool used to predict performance.

Dosage figures are based on a list that works like a “Who’s Who” of thoroughbred breeding.

About a hundred years ago, a French thoroughbred racing scholar named Lt. Col. J.J. Vuillier conducted a study of the top runners in England and France.

Vuilllier noticed that certain stallions kept appearing on those pedigrees. He studied their records and determined which characteristics they passed on.

He called these stallions the chefs-de-race or “chiefs of racing.” What’s more, he noticed that every decade or so, new stallions showed up on the list.

Chefs-de-race (Chiefs of Racing)

As of this writing, there are 210 stallions listed.

So. who’s among them? Legendary horses like Man O’War, Secretariat and War Admiral. So is modern stallion A.P. Indy, a leading sire whose stud fee is $300,000 for a live foal.

But who’s not on the list? For one, War Admiral’s famous-from-the-movies vanquisher Seabiscuit.

Nor is Storm Cat, the now-pensioned stallion who used to command $500,000 in stud fees.

Winning a US or UK Triple Crown title isn’t a lock for inclusion as a chef, either. Only six Triple Crown winners — three from the U.S. and three from the U.K. — are listed as chefs.

Of those US Triple Crown winners, Affirmed isn’t listed, but his famous rival Alydar is.

The Influential Genes of the Chefs

A stallion on the list is a given an aptitudinal designation that’s indicated by a letter, but it’s not S for “speed” or E for “endurance.” Think more metaphorically.

“Brilliant” is used for “speed.” And “Professional” is used for endurance or stamina.

So, B=Brilliant (speed), I=Intermediate, C=Classic, S=Solid and P=Professional(stamina).

And you read that from left to right, you can see what resembles a matter-of-degrees from Brilliant (fast) to Professional(tough).

Now, let’s go back to the chefs-de-race list.

When you look down the columns of names, you’ll see parentheses with the letters B, I, C, S, P. Some listings just have one letter, others have combinations of two.

Where the Numbers Come In

Now, here’s where dosage gets mathy and makes people’s heads spin.

When a chef-de-race is in a horse’s pedigree, a numerical value is determined by the generation that sire appears. That makes up the Dosage Profile.

The numbers are assigned along the B-I-C-S-P lines. Let’s take a look at current “Horse of the Year” Curlin, whose dosage profile is 9-3-8-0-0.

Remember B(rilliant) — I(ntermediate) — C(lassic) — S(olid) — P(rofessional) which means …

A Range from Speed to Stamina

No doubt, according to that layout of numbers — with so many to the left of center — Curlin is bred for speed. He’s also bred to go the distance of the Classic races like the US Triple Crown. But the numbers say he’s a little light on the endurance/stamina. After all, he lost his Belmont Stakes bid, a 1-1/2 mile race, to the filly Rags to Riches.

The stats also say that Curlin is a generation or two out from the chefs in his pedigree. The closet one is his grandfather Mr. Prospector, who came in second to Secretariat back in the day. Even coming in second to Secretariat, Mr. Prospector sired enough winners that he’s listed as a B/C (Brilliant and Classic).

However, other numbers — like Curlin’s $10.2 million of earnings at this writing — say that he’s the richest horse in the world. So, Curlin and his connections are doing something right.

Whether he can pass on “the good schtuff” to his descendants is a question for the future.

Just Probabilities, but Still …

But, statistics or no, horses are living beings who have good days and bad.

Still, handicappers and breeders pay attention to dosage as a statistic that can indicate probable performance.

FWIW, new chef-de-race A.P. Indy, who’s still active in the breeding shed, is a good example of when the variables come together and how dosage numbers work. In his case, according to the chart, he’s an I/C. He was the 1992 Horse of the Year. Although he scratched in the Kentucky Derby, he won the Belmont, the Breeders Cup Classic, and the Jockey Club Gold Cup.

Indy’s Dosage Profile is 13-10-20-3-0.

Remember – Brilliant-Intermediate-Classic-Solid-Professional.

He’s got some speed in him, all right, but he’s also got some distance runners, too. Those numbers right of center probably contributed to that 1-1/2 mile Belmont Stakes win.

Let’s go back here, scroll down the page and take a look at Indy’s pedigree. He’s a direct son of US Triple Crown winner Seattle Slew, plus Indy’s mother was sired by Triple Crown winner Secretariat.

He’s got Triple Crown winners in close generational proximity “on the top and bottom,” as horsemen say.

Which leads us to a little secret about dosage …

Common Sense in Statistical Form

If you breed the best to the best, your odds of getting the best are better.

Now, for the secret

I wish the link were still here. But when I was first curious about dosage, I did some websurfing. I saw the dosage numbers for the 2004 Kentucky Derby, the year that Smarty Jones made his Triple Crown bid. I was amazed to look at those Dosage Profiles and see what history proved out.

That the beloved Smarty Jones did not have the pedigree to go the distance of the Belmont Stakes. His DP has very little to the right of center. But Birdstone. the winner (and spoiler) did.

Check it out – stats from Pedigree Online:

• Smarty Jones – 10-3-8-1-0
• Birdstone – 7-8-9-0-2

For more reading on dosage:

From Thoroughbred Champions

Dosage: Pedigree & Performance by Stephen A. Roman, PhD

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Tags: A.P. Indy, Birdstone, chefs-de-race, Curlin, dosage, Smarty Jones, Triple Crown