A Brief Review of Dosage A Practical Approach:

Dosage, a technique for classifying Thoroughbred pedigrees by type, originated in the early part of this century from the research of the Frenchman Lt. Col. J. J. Vuillier. In his classic study of the extended pedigrees of the best runners in England and France, Vuillier (in LES CROISEMENTS RATIONNELS DANS LA RACE PURE) observed that few stallions appeared with great frequency. He called those stallions that did appear frequently chefs-de-race, which literally means “chiefs of the race.”  He also noted that the degree of inheritance attributed to these chefs was essentially constant in all pedigrees, the absolute value (or Dosage figure) varying from sire to sire. Furthermore, he demonstrated that in successive 15 to 20 year time frames, new series of chefs emerged which eventually established their own fixed degree of influence.

This process, in which new series of chefs periodically become dominant, provides a rational model for the evolution of the Thoroughbred racehorse. Vuillier believed that the objective in breeding should be to attain Dosage figures in the foal as close as possible to the established Dosage figures for the breed. For some time he practiced his theories successfully in the employ of H. H. The Aga Khan, breeder of such notables as Bahram, Majideh, Mahmoud, and Nasrullah, among many others.

Some years later, the Italian Dr. Franco Varola (in TYPOLOGY OF THE RACE HORSE and THE FUNCTIONAL DEVELOPMENT OF THE THOROUGHBRED) developed a modified version of Dosage that retained the principle that Thoroughbred evolution proceeds through the influence of a very small number of the stallions at stud in any era. Varola did, however, shift the emphasis from quantity (i.e., the degree of inheritance associated with individual sires) to quality (i.e., the pattern of aptitudinal traits inherited from key ancestors). Discounting the generation in which his expanded list of chefs appeared, he arrived at a distribution of aptitudinal traits in a given pedigree that described the "type" of the horse being analyzed. The most significant point made by Varola was that the characteristics transmitted by his chefs were not necessarily those they possessed as runners. The focus, instead, was entirely on the qualities passed on as breeding animals. (See Dosage Contribution)   Thus, in contrast to conventional pedigree analysis based on an historical perspective of ancestral performance, Dosage relies on the dynamics of inheritance. As an alternative and complementary method of pedigree interpretation, it may help avoid potential problems associated with the traditional concept of “breeding the best to the best.”

As we pointed out in the section: Female Families – Taproot Mares, Alec Wildenstein bases much of his breeding principles on those of his predecessors, notably The Aga Khan, and Tesio. Wildenstein also utilizes principles from the Dosage System in his work with breeding. He notes, “Dosage – at first I didn’t think it worked, and then I found that some patterns seem to be of significance. I have been working with that for the last four years. It’s not a fixed rule: you don’t need a DP of 60 to make a good horse. There is a certain rapport between the CD and the DI that seems to work. If you exceed that in either direction, it doesn’t seem to work.”

Our approach, which first appeared publicly as a series of articles in Leon Rasmussen's Bloodlines column in Daily Racing Form just prior to the 1981 Kentucky Derby, has been to fuse the basic ideas of Vuillier and Varola, incorporating both quantitative and qualitative components in the hope of providing additional insights. In order to establish greater utility, we chose to use more accessible four-generation pedigrees instead of the extended pedigrees used previously. We also re-introduced Vuillier's approximation of a genetic effect by halving the influence of any chef in each successive earlier generation(s). Finally, we established a statistical method for evaluating the results of our analysis. In this framework, Dosage in its latest configuration was developed.

Each chef is assigned to one or two of five aptitudinal groups (Brilliant, Intermediate, Classic, Solid, and Professional) covering the spectrum of speed to endurance. The assignments are made to best reflect the traits that these stallions predictably and consistently transmit to their offspring. For bookkeeping purposes we assign a total potential value of 16 points to each generation.

Since there are, progressively, one, two, four, and eight sires in the first four generations, chefs that appear among these sires will contribute 16, 8, 4, and 2 points each as we work back. The points for all chefs present are then tallied in the appropriate aptitude columns. Chefs that confer two aptitudinal characteristics have their points split between the two aptitudes. In the end, the total points in each column produce the Dosage Profile, a series of five numbers that reflect the relative proportions of each of the five aptitudes: 

(B)rilliant:             These chef-de-race sires transmit an early brilliant factor.  They are associated with early developing speed.

(I)ntermediate:     These sires transmit “miler” talent.  They are difficult to find these days.

(C)lassic:              These chef-de-race sires pass on “classic” distance.  In America, 1¼  miles, and internationally, 1½  miles.

(S)tamina:             These chef-de-race sires possess staying aptitudinal talent beyond the 1½ mile.

(P)rofessional:      This aptitude tends towards more than 2 miles (2½  and 3 miles).

The next three sections detail the main calculations that the dosage system utilizes to represent certain characteristics of a horse:

Dosage Profile

A Roman dosage profile (DP) is derived from the points of chef found in four generations of a pedigree and where they fall on the aptitudinal chart. (Cigar's DP, for example, is 7‑2‑10‑1‑0.)

Since breeding has changed in the last century to emphasize speed over stamina (particularly in America), modern pedigrees are likely to lean toward brilliant‑to‑classic, as does Cigar's. One would be hard pressed today to find top runners without at least some brilliant-to-classic influence in their pedigrees‑as was the case with Man O' War (0-0‑4‑12‑8) and 1930s champions Discovery (0-0-4-4‑6), Gallant Fox (0‑0‑16‑8,4), and Challedon (0‑0‑16-4‑2). Presently, the reverse is true: one is more likely to find minimal‑to‑nonexistent influence from the professional end, as with Thunder Gulch (10‑2‑8-0-0), champion Timber Country (11‑5‑22‑0‑0), and leading sire Danzig (15‑11‑14-4-0).

Dosage Index

The dosage index (DI) is derived from the profile to reflect the ratio of speed‑to‑stamina in a pedigree. This is calculated by adding points from the two "speed" categories (brilliant and intermediate) plus half of those from the classic (middle) category, and dividing that total by the points from the two stamina categories (solid and professional), plus the other half of the classic points. The higher the DI, the more speed is supposedly present in the pedigree.  Average North American DI is 2.40, thus, Cigar's DI of 2.33 indicates he has slightly more stamina in his pedigree than average. A 4.00 DI is generally the cutoff, over which a horse is considered not likely to get the American classic distance of a mile and a quarter as a three year old on the first Saturday in May.

Center of Distribution

Center of distribution (CD) is a more complicated calculation derived from the profile. Theoretically, as with DI, the higher the CD, the lower a horse's distance potential. Average CD in this country is +.70. Apple Tree (Fr) winner of three 1-½ -mile Grade/Group 1 events in three countries in 1993-’94, had a CD of ‑.20. Man O' War apparently could have run all day and into the night with a ‑1.17 CD. Conversely, Secretariat’s CD of +.90 was above average yet he was arguably the most eminently capable runner at up to 1½  miles that this country has seen in years.  A common misconception is that the center of distribution is a direct indicator of the optimal running distance for a thoroughbred horse. This is not true, as the center of distribution is only an indicator of speed in relation to distance.  An advantage of UltiMate 2000^© is the automatic computation of a projected optimal running distance in relation to the inter-relationship between dosage index and the center of distribution.  A red ‘X’ indicates the CD itself.

Dosage Contribution

A particular facet of dosage, which goes ignored or overlooked, by most of the thoroughbred breeding community is the significance of the sire’s dosage contribution and the dam’s dosage contribution.  What catalogs and stallion ads give you is the actual dosage of the horse, not what it contributes as a sire or dam.  Because dosage only takes into account the first four generations in each parent’s pedigree, the last branch of the parent’s pedigree is no longer a factor in calculating the dosage of the resulting foal (a new generation).  Therefore one finds quite a difference in a horse’s own dosage and the dosage it can contribute as a sire or dam as illustrated in the diagram below. 

Prospective Foal’s Dosage Contribution as Sire or Dam

The prospective foal’s actual dosage does not enter into consideration when it comes time to breed it.  As can be seen, the foal’s actual dosage is (4-0-16-4-2), however, its contributing dosage is (1-0-6-2-1). Also of importance is the improvement in the prospective foals contributing dosage (1-0-6-2-1) versus the dam’s contributing dosage (2-0-4-4-0).  Therefore this prospective foal can bring more desirable contributing numbers to its own offspring as a sire or dam, a desired result in any breeding.  Another advantage of the UltiMate 2000^© software is that each of these dosages is calculated automatically, both in actual horses and hypothetical breeding.

Research using the described methodology as a tool for pedigree classification has resulted in many revealing observations including the following:

1.      There is a direct correlation between the D.I. and C.D. and performance at varying distances as determined from separate populations of stakes winning sprinters, middle distance runners, and routers. As expected, the sprinters have the highest values (reflecting the importance of speed in short races), the routers have the lowest (confirming the need for endurance in long races), and the middle distance runners fall in between. In general, the Dosage figures correlate with the average distance of the races in each category. The precision of the technique is highlighted in the table below where average Dosage figures are displayed for specific distances between 5.5 and 12 furlongs for open stakes between 1983 and 2004. The correlation is virtually linear, confirming the direct relationship between distance and the speed/stamina characteristics of pedigrees as expressed by Dosage figures.

2. Elite Thoroughbreds as a group (e.g., champions, classic winners, leading sires) have significantly lower DI's and CD's than the general population of stakes winners, suggesting that outstanding performance on the track or at stud benefits from a large component of inherited stamina. There is no evidence, however, of an inherent superiority associated with lower Dosage figures. In other words, a lower DI is not better than a higher DI. Rather, the lower Dosage figures merely reflect the fact that our most prestigious races are run at longer distances and that successful competitors are aptitudinally suited to those races. Elite Thoroughbreds also have a higher point total in their DP than do typical stakes winners, acknowledging the fact that they tend to be somewhat better bred, at least to the extent that more chefs in a pedigree correlate with superior breeding stock.

3. Only two winners of the Kentucky Derby since 1940 (Strike the Gold and Real Quiet), and only three winners of the Belmont Stakes over the same time frame (Damascus, Conquistador Cielo, and Creme Fraiche) have had a DI above 4.00. This is in direct contrast to dirt stakes winners in general, of which about one-third have a DI greater than 4.00 and for which the average DI is slightly higher than 4.00. The combination of Dosage with our discovery that 21 of the 26 winners of the Kentucky Derby since 1972 were ranked as a juvenile within 10 pounds of the highweight on the Experimental Free Handicap or were named juvenile champion in another country has become an especially powerful tool in isolating the true classic contenders. In the four races where a "dual qualifier" (i.e., DI and two-year-old form) failed to win, three finished second, and in three of those races, a qualifier subsequently won either the Preakness or Belmont Stakes. The implications of this result are that a pedigree suited to distance, along with a demonstration of high-class, early maturity are more important for classic performance than other factors such as form in the pre-Derby preps at distances less than ten furlongs. Over the past 26 years, an average of only three starters per Derby have met both criteria, including long-shot winners Genuine Risk, Gato del Sol, Ferdinand, Alysheba, Unbridled, Sea Hero, Go for Gin, and Thunder Gulch. In addition, the "dual qualifiers" have accounted for 9 exactas and 5 trifectas. Thirty-six percent of all "dual qualifiers" won at least one classic race.

4. The average DI of juvenile stakes winners steadily decreases throughout the season, indicating a larger speed component in the pedigree of winners early in the year relative to winners later on. This phenomenon parallels the need for greater stamina as the distances of races for two-year-olds increase through the year.

5. The DI of many steeplechase champions since 1972 exceeds the classic guideline figure of 4.00 despite the long distances associated with steeplechase racing. This result suggests that the pace of these races is well within the ability of speed-bred runners and that their quickness over the jumps can be a more important factor for success. The remainder of steeplechase champions has had a DI close to 1.00 or less, more typical of expectations for competitors at very long distances. Surprisingly, there are few steeplechase champions with a DI in the range of middle distance flat racers.

6. The average DI of stakes winners at tracks favoring speed is higher than the average DI of stakes winners at tracks where speed is less favored. This result is consistent with the observation that brilliantly bred runners often carry their speed further on the speed-oriented surface.

7. Turf stakes winners have, on average, a lower DI than stakes winners on dirt. Furthermore, the turf runners have a significantly greater representation of Solid and Professional chefs in their pedigree. This result is consistent with the observation that turf races are run at a longer average distance than are races on dirt.

The studies discussed here are based on large populations that reflect statistically significant trends.

The Dosage user must recognize, however, that within these populations there is great variation. Accordingly, Dosage figures for an individual may not conform to those of the whole population. Greater accuracy and increased predictability depends in large part on a continual modification and refinement of the chef-de-race list, guided by the principle of a better description of reality.

Dosage Statistics (1983-2004)

The following table provides basic Dosage data for open stakes winners between 1983 and 2004. The data are presented by racing categories of surface, distance, age, and class of race. Each category includes the number of stakes winners in the sample (SW's), the average Dosage Index (ADI), the average Center of Distribution (ACD), the average number of points in each of the five aptitude groups (B=Brilliant, I=Intermediate, C=Classic, S=Solid, P=Professional in order from left to right) that comprise the Dosage Profile (DP), the composite Dosage Index (CDI), the composite Center of Distribution (CCD), and the average distance of the races in the category. Composite Dosage figures are calculated in the usual way by using the average points in each aptitude group. The CDI and CCD reflect the population as a whole rather than the average of each of the individuals in the population.

As the annual weeping and gnashing of teeth begins over who will or won’t be able to get the mile and a quarter come that first Saturday in May, once again I find myself flashing back to those long ago Saturday afternoon broadcasts from the Big A, Belmont or the Spa, broadcasts that those of us who grew up in the city were favored with each week. Once again, I am transformed. I can hear the clarion call of Fred Cappasella, quavering with emotion, as the riveting, struggling epics unfold, piercing through the roar of the crowd, as it swells to a thrilling crescendo. I can see them all as clearly in my mind’s eye, as ever they were on that old black and white 12-inch -----Round Table, Kelso, Gun Bow, Beau Purple, Mongo, Dr. Fager, Damascus, Buckpasser----- how brave, swift and magnificent they were----- and wouldn’t any one of them just make a shambles of this current crop of redoubtables?

Is memory more and more sweetly tinged by the passage of time? No doubt it is----still, I can’t dismiss the feeling that something is not right here. Some elusive, tangible, though perhaps inexpressible quality, seems to have been mislaid through the passing of the generations. Certainly, one might propose that horses like Forego, John Henry, and more recently Cigar and Skip Away would not be out of place among those aforementioned, bygone heroes, and get no argument from me. Yet today, as the new millennium dawns, something palpable about the horses themselves seems to be not “as it once was.” They don’t make ‘em like they used to...hmmm... Well, one could ponder these things forever. Truth be known, perception is reality, and we must clarify our perceptions.

So let’s peruse the current list of chefs-de-race, and see whether or not there are any clues here that might illuminate this quandary. By my count, there are 254 aptitudinal designations assigned to the various chefs. These are distributed unequally among the five-aptitudinal categories. If we figure out the percentage of total aptitudes by aptitudinal category, perhaps it might reveal something. The breakdown is as follows:

Very interesting, but not what I was looking for. What if we form two separate groups of chefs, delineate at about mid-century, and see if there is any difference between them. Bold Ruler was a prepotent sire who emerged about this time, (1954, to be exact) so why not separate the two groups into “chefs foaled prior to 1954” and “chefs foaled after 1953”? Seems fair enough to me.

Now we’re getting somewhere. Aptitudinal designations to the post-1953 group have shifted toward the middle and slightly left, and the Professional aptitude has almost blipped off the screen. So we’ll assign half of the Classic aptitudes toward “Speed,” and half toward “Stamina” and see how our two groups shake out.

Percentage of aptitudinal designations assigned to all chefs:
Speed...57.28%,  Stamina....42.72%

Percentage of aptitudinal designations assigned to chefs foaled prior to 1954:
Speed...54.48%,  Stamina....45.52%

Percentage of aptitudinal designations assigned to chefs foaled after 1953:
Speed...61.01%,  Stamina....38.99%

So we have an aptitudinal shift of about 13% from stamina toward speed, the pre-1954 chefs possessed of more stamina-based aptitudes, the post 1953 chefs possessed of more speed-based aptitudes. Now there’s a treasure trove for students of the obvious----like me----who suspected something was amiss all along. What is one to infer from this information? Is this just a quirk of statistics, or does it have some real relevance to the Thoroughbred and the industry that is built around him? How, why and when did this happen? Is it a good thing, or a bad thing? Perhaps we might arrive at some answers to what appears, at a glance, to be an alarming metamorphosis.

Obviously, we see a reflection of the ever-decreasing opportunities for stamina-bred horses, typified by the leftward bent of the more recent group of the breed’s most influential progenitors. So why have these opportunities decreased? Was there a nationwide conspiracy among racing secretaries to deprive the owners and trainers of stamina-bred horses equal convenience? Was the genetic potentiality for expression of stamina improperly nurtured by the breeding community, so that it recessed to the degree we have observed? Were there other, peripheral factors involved? Needless to say, at this point, it would be problematical for a breeder or breeders to begin to “retrieve” the waning Professional aptitude from existing gene pools. The most recent chefs who express that aptitude are Stage Door Johnny and Vaguely Noble, both foaled in 1965, Run the Gantlet, foaled in 1968, and Ela-Mana-Mou, foaled in 1976, placing at least three of them pretty far back in most contemporary pedigrees. Should the task be undertaken merely upon a whim of nostalgia, or is there a greater, practical, ethical imperative to be heeded here?

The aptitudinal shift toward the expression of speed that we have observed between our two groups of chefs---- considering their profound influence on the breed---- must inevitably result in the emergence of a median Thoroughbred type with more muscle and correspondingly less bone. This type would thus possess a physical predisposition toward more dynamic acceleration and also more frequent and traumatic injury. The basic tenets of selective breeding, inheritance, and physical dynamics, would compel it to emerge. Whenever men have undertaken the selective breeding of animals for utilitarian or sporting purposes, type has always adjusted toward purpose. In a holistic sense, I perceive to be in the majority today a noticeably more muscular, less angulated and conformationally less graceful, less elegant type of Thoroughbred----- who although perhaps faster than his forbears----for shorter distances---- lacks their endurance and soundness. Has the breed fashioned the marketplace, or has the marketplace genotyped the breed?

The paradigm shift toward speed, and its inherent unsoundness, was radicalized by the advent of modern veterinary medicine and rules changes that allowed horses to race on medication. This enabled many individuals who without the aid of science, would have fallen by the wayside, to prosper on the track and later on in the breeding shed. A large enough percentage of these individuals then became genetically influential---- enough to engender the emergence of similar types, with similar infirmities and genetic legacy. Their offspring were then inherently less and less able to endure the rigors of route racing, weight carrying, and racing without medication---- as races became shorter, weights less burdensome, medication rules more liberal and the attrition rates more debilitating. Like tends to beget like----it is the essence of selective breeding. Hence, the type we see today . . . tilted dramatically toward speed, self-perpetuating unsoundness, and not so incidentally, precocity.

“Precocity”----sounds nice, doesn’t it? Webster defines it as “premature development.” Purveyors of “fashionably” bred thoroughbreds have recently chosen to define it as the 10-second furlong, toward what practical purpose one can only imagine. Precocious speed, passed on by precocious sires, that have little else to show for their careers as racehorses, are doomed to an early demise by their own precocity---- we’ve all read the sire advertisements. It is the number one buzzword of the commercial breeder, it is the quality most sought-after by the Thoroughbred “investor.” Precocity, I would suggest, is the last refuge of those who are unable to imply a sense of longevity, and the first concern of those who lack a sense of propriety. It is damnation with faint praise. Precocity betrays the Thoroughbred. It is the subtle admission that his soundness and physical well-being have been compromised for a quick return on investment. It is the final stage of a phenotype distorted by human greed. Think about it.

Should the racing industry have the ethics and foresight to adopt a pro-forma geared toward re-establishing a more comprehensive and results-oriented program of stamina-based venues, Thoroughbred type would be impelled to emerge toward it.

Breeders who sense deterioration toward speed could also impel a more balanced type to emerge, by gearing their programs toward making use of the present stamina-based venues. By so doing, they could motivate the industry toward reinforcing the reversion to a more sound, balanced type as reflected by our pre-1953 group of chefs. As the demand for these venues increases, it should be met. Eventually, it may even become feasible to reassess medication rules, without crippling either the industry or the breed.

Either way, it won’t happen overnight or by serendipity. It will require a highly evolved sense of husbandry, horsemanship, sportsmanship and fair play, and for some of the “prime movers” to dismiss their notions that “it’s all about the money.” Because, when it comes right down to it, if we have nothing else, we have our fondly smiling sense of nostalgia to remind us----as it does every now and then, in those hazy, golden moments----its all about the horses.

When considering dosage in the breeding of thoroughbreds, it is important not to ignore the physical comparison, or phenotype*.  No matter how well the contributing dosage of the sire and dam equate into a prospective foal, breeding two horses of extreme phenotypes will not produce a proportionately correct foal possessing a balance of the sire and dam’s physical attributes and characteristics.  Keep in mind that Dosage is only one of many tools that are necessary for evaluating pedigrees and for predicting the performance aptitude of a resulting foal.

*Several critical measurements of a horse are used to determine how it is “balanced” in relationship to its power, stride and body weight (trunk size).  These factors are expressed visually into a dozen groupings based on that relative “balance.”  As the proportions vary, the horse’s physical structure will adapt to either distance or speed.