The 23 New Chefs-de-Race Added by Dr. Steven Roman and the Impact They Will Have

The Dosage system was developed to provide breeders and bettors with a numerical way to evaluate the balance of speed and stamina inherited by a horse. The method is not a magic formula; it was built from the observation that a small number of influential stallions transmit traits of precocity or stamina to their descendants. At the beginning of the 20th century, the French military officer J. J. Vuillier began identifying these sires, which he called chefs-de-race (literally “masters of the breed”), grouping them according to aptitude. The Italian researcher Franco Varola expanded the idea in the 1960s. The system remained relatively obscure until columnist Leon Rasmussen published an article in 1981 in the Daily Racing Form introducing the approach of Steven A. Roman, PhD, a scientist who refined Dosage using statistical analysis. In his book Dosage: Pedigree & Performance, Roman argues that his research is empirical and supported by tables and regression models to relate Dosage and distance. According to Roman, winners of classic races usually present a Dosage Index (DI) between 2.00 and 2.60, while pure sprinters fall between 4.00 and 4.75. This approach influenced breeding and yearling selection in the following decades.

Into Mischief (Harlan’s Holiday) in his paddock at Spendthrift Farm, Lexington, Kentucky.

Dosage is a numerical tool that attempts to quantify the balance of speed and stamina in a pedigree. Unlike other analyses, it does not attempt to examine the entire family tree, but focuses only on those stallions that have demonstrated exceptional influence on the breed: the chefs-de-race. Currently, more than 200 chefs are recognized. Each chef contributes points to the immediate generations of the horse analyzed: 16 points if present in the first generation (sire), 8 in the second (grandparents), 4 in the third (great-grandparents), and 2 in the fourth. This weighting is based on the idea that an ancestor’s influence diminishes with each generation. Only recognized chefs contribute points; any other stallion, no matter how famous, does not enter into the calculation.

The chefs are classified into five aptitude groups, covering the full spectrum between speed and stamina. These groups are Brilliant, Intermediate, Classic, Solid, and Professional (B, I, C, S, and P), ordered from least to greatest stamina. A chef-de-race may belong to more than one category; for example, Mr. Prospector is classified as Brilliant/Classic, so his points are divided equally between both categories. This reflects that certain stallions transmit both speed and stamina.

The sum of all points generated by the chefs in each category constitutes the Dosage Profile (DP), a series of five numbers showing how much influence the horse inherited in each aptitude. For example, a sprinter such as Squirtle Squirt showed a DP leaning to the left with a majority of points in the Brilliant category, indicating a predominance of speed. In contrast, the stayer Spring Marathon had the highest figure in the Professional category, reflecting a strong inclination toward stamina.

Roman’s book emphasizes that the DP should not be analyzed only by the total number of points, but by their distribution. In chapter 10, it states that the DP is “the core of modern Dosage methodology” and that the way points are distributed significantly affects performance; horses with at least ten points in the Brilliant category are more likely to win in speed races than those with fewer than ten, even if both share the same DI.

The Dosage Index is a simple ratio: speed points (Brilliant + Intermediate + half of Classic) are divided by stamina points (Solid + Professional + the other half of Classic). A DI of 1.00 indicates a perfect balance; high values (above 3.0) point to a greater proportion of speed and, according to Roman, are characteristic of horses suited to shorter distances. Historically, it was claimed that no Kentucky Derby winner had a DI above 4.00, although Strike the Gold’s victory in 1991 with an initial DI of 9.0 demonstrated that exceptions exist. After Alydar was recognized as a chef and added stamina points, Strike the Gold’s DI was corrected to 2.6.

The Center of Distribution (CD) marks the balance point of the profile. It is calculated using the formula [(2 × Brilliant + Intermediate) – (Solid + 2 × Professional)] divided by the total points. The CD is expressed on a scale from +2.00 (pure sprinters) to –2.00 (extreme stayers). For example, Lochsong, a European sprint champion, had a DP of 6-0-0-0-0 (only Brilliant points) and a CD of +2.00, indicating purely speed influence.

Although Dosage has been a useful tool for approximating aptitude, Roman warns that his method is not a traditional statistical system. The 2002 edition of Dosage: Pedigree & Performance insists that conclusions are based on race data, but interpretation must combine science and art. Roman himself acknowledges that the Dosage Index is a guide, not a law: “There are statistical principles that will hold true in most cases, but exceptions will always arise.” Some experts note that chef lists were not updated quickly enough, so modern pedigrees could include few or no chefs, producing extreme DIs that did not reflect a horse’s true ability.

In 2023, Roman thoroughly revised the North American chef list for the first time in a decade. According to a letter published by The Dirty Horse Club, 24 highly influential stallions were identified, 23 of them new chefs-de-race. The team analyzed each stallion’s progeny, calculating the Average Winning Distance (AWD) and the average Center of Distribution of their winners. When a stallion had at least three offspring among the top 150 in the statistics, it was evaluated whether assigning it to a category aligned the average CD of its winners with the expected value. For example, Tapit’s offspring had an average winning distance of 8.67 furlongs and an average CD of 0.69; classifying Tapit as Classic adjusted the CD to 0.45, consistent with a classic-type stallion.

This update eliminates the need for “non-chef notable sires” lists and integrates Australian/New Zealand chefs into the main list, improving profile accuracy. Roman also notes that conduit mares — those that amplify or attenuate chef influence in the female line — remain important, but the new chefs reduce reliance on extreme scores and allow maternal influence to be more subtle.

Roman added nineteen contemporary American stallions along with some imports influencing North America. They were classified by aptitude as follows:

Sire	Category
Munnings	Brilliant – Intermediate
In Excess	Brilliant – Intermediate
Speightstown	Brilliant – Intermediate
Rubiano	Brilliant – Intermediate
Into Mischief	Brilliant – Classic
Elusive Quality	Brilliant – Classic
More Than Ready	Brilliant – Classic
Candy Ride	Brilliant – Classic
Uncle Mo	Intermediate – Classic
Street Cry	Intermediate – Classic
Scat Daddy	Intermediate – Classic
Quality Road	Intermediate – Classic
Distorted Humor	Intermediate – Classic
Tiznow	Intermediate – Classic
Quiet American	Classic
Medaglia d’Oro	Classic
Curlin	Classic
Tapit	Classic
Kitten’s Joy	Classic
Dynaformer	Classic
Empire Maker	Classic – Solid
English Channel	Solid – Professional
Alleged	Classic – Professional

Brilliant (4f–6f), Intermediate (7f–9f), Classic (10f–12f), Solid (13f–15f), Professional (16f+).

Among the new chefs, Candy Ride stands out as the fourth Argentine stallion on the list after Congreve, Sideral, and Forli. Candy Ride was unbeaten in Argentina and the United States, setting a world record at one mile and a track record in the Pacific Classic. As a stallion, he has produced champions on dirt and turf such as Gun Runner and Shared Belief. His classification as Brilliant/Classic reflects his ability to transmit both early speed and classic-distance aptitude. His predecessors had similar impact. Congreve (1924) became a patriarch of Argentine breeding; Sideral, by Seductor, excelled in stamina races and sired stayers; Forli, unbeaten in Argentina, was exported to the United States and influenced global breeding through horses like Thatch, Lisadell, and Special.

The inclusion of these 23 stallions has immediate practical effects for breeders and analysts, beginning with a structural correction of extreme profiles. Previously, pedigrees dominated by lines such as Into Mischief, Tapit, or Curlin produced artificially unbalanced Dosage Profiles because these sires did not contribute points as chefs. Their influence was diluted across generations, inflating the DI above 4.0 and misrepresenting true aptitude. Now, with proper classification, points are assigned correctly, reducing inflated indices and eliminating the need for manual adjustments.

At the same time, the system achieves finer differentiation between pure speed and functional balance. Stallions like Munnings, Speightstown, Rubiano, and In Excess classified as Brilliant–Intermediate show they are not strictly sprinters, while Candy Ride, More Than Ready, and Elusive Quality as Brilliant–Classic confirm dual capacity. This changes DP interpretation: it is no longer enough to look at Brilliant weight; distribution toward Classic becomes key.

This update also integrates the contemporary reality of North American breeding. Including dominant stallions like Into Mischief, Curlin, Tapit, and Uncle Mo ensures the system reflects modern genetics rather than past snapshots. Roman justifies this with statistical consistency in producing stakes winners across surfaces and distances.

Operationally, breeders must recalibrate analyses. Crosses that once appeared unbalanced may now show harmony. For example, a Munnings × Tapit mating now generates direct points in Brilliant–Intermediate and Classic, altering the profile. This influences mating decisions and improves versatility and commercial appeal.

Dosage should not be seen as a predictive formula, but as a complementary indicator. Roman explains that a DI between 2.0 and 2.6 correlates with success at 10–12 furlongs, yet acknowledges that breeding and training cannot be reduced to numbers. Triple Crown history shows horses with DIs above 4.0 can still win the Kentucky Derby under the right conditions.

The system’s main strength lies in its reference value: it indicates whether a pedigree leans toward speed or stamina and allows comparison within crops. It also helps bettors eliminate pure sprinters in staying races. Weaknesses include past lack of updates (now corrected), omission of some influential sires through female lines, and the fact that only stallions are scored, though mares are crucial. Roman recognizes this through the concept of conduit mares.

Dosage has endured for over a century as a practical tool to understand pedigree balance. Steven A. Roman’s work provided statistical grounding and periodic updates. His book explains its history, methodology, and applications, showing how science and empiricism can guide decisions. The addition of 23 new chefs modernizes the system, reduces extreme indices, and offers a more accurate reading of inherited aptitude. For breeders, it is an invitation to reassess mating strategies; for analysts, a reminder that no index replaces a full evaluation of conformation, performance, and environment. Speed and stamina remain the foundation, but interpretation will always remain an art.