Dams Are More Important Than Sires????–Part 3

As promised, below are the results for the various groups discussed in my previous post. Just to review, A sires are G1 winners, B sires are all others, A dams are graded stakes winners (G1-G2-G3), and B dams are nongraded stakes winners. APPPSSW stands for average Performance Points per stakes winner, a measure of the quality of stakes winners involved (665 being average).

Group          Foals          Stakes Winners          %          APPPSW          PPI (Result)

A Sires         3,971                    207                    5.21             944                     2.25

B Sires          1,596                     76                    4.76             699                     1.52

A Dams        1,500                     78                    5.20             981                     2.33

B Dams        4.067                   205                    5.04            840                    1.94

Totals            5,567                   283                   5.08            879                     2.05

There is not much difference among the four groups by percentage of stakes winners from foals. APPPSW (quality of stakes winners) does show some significant differences, with A dams being first at 981 (665 being average), followed by A sires at 944, B dams at 840, and B sires at 699. PPIs (results) follow suit, with A dams being best at 2.33, followed by A sires at 2.25, B dams at 1.94, and B sires at 1.52.

Group          Foals          Stakes Winners          %          APPPSW          PPI (Result)

AA                1,140                     55                      4.82           1,063                   2.35

AB                2,831                    152                     5.37              902                   2.22

BA                   360                     23                     6.39              784                   2.29

BB                 1,236                    53                     4.29               663                   1.30

BA is best by percentage of stakes winners from foals at 6.39, followed by AB at 5.37, AA at 4.82, and BB at 4.29. AA is best by APPPSW at 1,063, followed by AB at 902, BA at 784, and BB at 663. Taking both factors into account, AA is best by PPI (results) at 2.35, closely followed by BA at 2.29 and AB at 2.22, with BB a distant trailer at 1.30.

These are the absolute results. What is more important is the results versus the prices, which are summarized in the charts below.

Group          Foals          Price Index          PPI (Result)          Difference

A Sires         3,971                 1.70                      2.25                        +0.55

B Sires         1,596                 1.47                      1.52                         +0.05

A Dams       1,500                2.04                      2.33                        +0.29

B Dams       4,067                1.49                      1.94                         +0.45

Totals          5,567                 1.64                      2.05                        +0.41

All four groups have positive results (PPI higher than Price Index), which is what you want to see. This is because all foals above are out of stakes winners, and such foals collectively had better results than warranted by their prices. A sires are best at +0.55, followed by B dams at +0.45, A dams at +0.29, and B sires at +0.05.

Group          Foals          Price Index          PPI (Result)          Difference

AA                1,140                  2.06                    2.35                        +0.29

AB                2,831                  1.56                     2.22                        +0.66

BA                   360                  1.95                     2.29                        +0.34

BB                1,236                  1.33                     1.30                        –0.03

AA is logically expected to be much better than BB. That is indeed the case in absolute terms (2.35 to 1.30). It is also the case in terms of prices versus results (AA +0.29, BB –0.03). Note that BB was the only one of the four groups which had a negative result relative to its prices.

This whole study was constructed in order to examine AB versus BA. To review, AB involves a better sire with a good mare. BA involves a good sire with a better mare. If BA produces better results than AB, the theory that dams might be more important than sires is supported.

BA did produce slightly better results than AB (2.29 to 2.22). But considering the prices involved (1.95 for BA and 1.56 for BA), that is a Pyrrhic victory. In terms of prices versus results, AB was by far the best at +0.66, BA was second at +0.34, followed closely by AA at +0.29. BB had a negative result (–0.03).

Considering the prices involved, BA was NOT any better than AB. The opposite was true. AB was considerably better than BA. This does NOT support the theory that dams are more important than sires.

I mentioned before that this whole project was “quick and dirty.” Therefore, it should be taken with a few grains of salt. Perhaps I should think of a better approach to this whole concept, one that incorporates all foals, not just foals out of stakes winners.

I mentioned in my previous post that interpretation plays a big role in this game. Using G1 winners as the “better” sires has a lot to do with these results. The fact of the matter is that many of the best sires of these sales foals of 2008-2011 were NOT G1 winners. Most of them were, but many of them were not. Some of the ones who were NOT G1 winners include Distorted Humor, Dynaformer, and Pulpit (all G2 winners), as well as Malibu Moon (merely a winner, not even a stakes winner).

I think the problem with the original scientific treatise and the reason it came to the erroneous conclusion that dams might be more important than sires is its definition of an “elite” sire. It ranked the sires based on their race records. The sires with the best race records were considered “elite” sires. All others were considered “nonelite.”

Now it is true that the best racehorses generally make the best sires. Emphasis on the generally. It is also true that many of the best racehorses turn out to be indifferent sires or worse. And a very few racehorses who were not G1 winners turn out to be excellent sires.

I think the original scientific treatise should have used a different criterion for separating “elite” from “nonelite” sires, something more to do with their actual sire records and nothing to do with their race records. Something like AEI or percentage of stakes winners from foals or even the prices of their foals sold at public auction. If they had used a different criterion more related to actual sire success (and having nothing to do do with race records), I think they might have come up with a very different result.

Perhaps I will try to explain this in general statistical terms. The correlation between a sire’s race record and his success as a sire is positive but weak. That is because, as Byron correctly pointed out, you almost have to be a G1 winner in the first place to have a decent shot at stud. Therefore, the supply of sires who are G1 winners is plentiful. Which makes them relatively cheap (except of course for the few who are actually any good at stud).

The dams’ side of the equation is quite different. The correlation between a dam’s race record and her success as a broodmare is both positive and strong, much stronger than in the case of sires. That is because the supply of broodmares who are graded winners (or any other definition of excellence you choose) will always be low. Low supply, good results, high demand.

Perhaps the safest thing to say about all of this is that a sire is still 50% and a dam is still 50% of a foal’s genetic inheritance. As far as we know the two are still equally important.

Because the general consensus seems to be that sires are more important than dams, believing the opposite and placing more emphasis on dams than sires might not be a bad idea. Iconoclasm is its own reward.

Reminds me of a story about the late Alfred G. Vanderbilt. Someone asked him what was his breeding strategy. “My strategy is to breed my Discovery mares to something,” he supposedly replied. Perhaps a little oversimplified, but you get the general idea.

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2 Responses to Dams Are More Important Than Sires????–Part 3

  1. Dougal Steel says:

    Hi there
    I read somewhere that you did some research into the effect of broodmare age on producing stakes winners. That old chestnut. Do you have a link to that ananysis?

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