“The present pedigree analysis study provides evidence suggesting
that maternal heritability of athletic performance may be a
stronger contributor than paternal heritability to race ability.”
So concludes a scientific paper titled “Potential role of maternal lineage in the thoroughbred breeding strategy.” By clicking on the link above, you may read a post by Byron Rogers which summarizes the conclusions of the original scientific treatise and links back to it. Byron adds some statistics and conclusions of his own. Be forewarned, however, that if you think my statistics are difficult to understand, the statistics presented therein are even more abstruse.
Be that as it may, the conclusions may be summarized thusly in a nutshell: Dams may be more important than sires in predicting racetrack success from pedigrees.
That is an intriguing idea and has lots of emotional appeal to a lot of people, mainly because it is so far the opposite of the general consensus that sires are more important than dams.
I can think of some examples that support this hypothesis. Perhaps the clearest example is Jonesboro (2002 colt by Sefapiano out of Mom’s Command, by Top Command). Jonesboro was a G2 winner and an earner of $1,550,685 (3,051 Performance Points).
Sefapiano was not a very good sire (albeit somewhat underrated). Mom’s Command was 1985 champion three-year-old filly. In this case the combination of a bad sire with an excellent (in terms of racing class) dam worked out quite well. Mom’s Command was 20 years old when she produced Jonesboro, which is one reason Jonesboro sold for only $27,000 as a yearling. That was the highest price for any yearling by Sefapiano in 2003. The other five sold for $19,700, $7,500, $7,200, $4,000, and $2,500.
A more recent example might be 2011 Kentucky Derby winner and champion three-year-old Animal Kingdom (Leroidesanimaux out of Dalicia, by Acatenango). Lersoidesanimauc was not a very good sire (other than Animal Kingdom). Animal Kingdom sold for $100,000 as a yearling in 2009, but the 20 yearlings by Leroidesanimaux sold in 2009 averaged only $21,717 and had a median of $6,062.
Dalicia, on the other hand, was a G3 winner in Germany and was by a very good sire (Acatenango). So you could interpret that to mean that Animal Kingdom was by a poor sire out of a very good dam, the same pattern as Jonesboro.
Actually, that is a matter of interpretation. Leroidesanimaux was a very good racehorse (2005 champion turf horse), a much better racehorse than Sefapiano (record of 4-2-2-0 for earnings of $37,793). If you look at it that way, you could also say that Animal Kingdom was by a very good racehorse (but indifferent sire) out of a very good dam. Animal Kingdom might not be the best of examples, therefore, except that he illustrates that interpretation plays a big role in this game.
The most obvious counter example is Triple Crown winner American Pharoah (Pioneerof the Nile out of Littleprincessemma, by Yankee Gentleman). Pioneerof the Nile is a pretty good sire. Littleprincessemma was unplaced in two starts. Yankee Gentleman is no great shakes as a broodmare sire (other than American Pharoah).
The second dam is the Ecliptical mare Exclusive Rosette, a very minor restricted stakes winner with a record of 17-3-0-3 for earnings of $27,281 (a good example of black type being misleading). The third dam (Zetta Jet) was unplaced in five starts. The fourth dam (Queen Zetta) was unplaced in six starts. Exclusive Rosette did produce G2 winner Stormin Wolf and G3 winner Misty Rosette (both by Stormin Fever).
So the female line of American Pharoah is not particularly impressive. On a scale of ten (ten being best), I would have to give it about a five. You look at his pedigree and conclude that he must have gotten his talent from his sire, not his dam or female line.
Which is not at all unusual. Many of the best racehorses are by good sires out of undistinguished dams (although as Byron correctly points out, that is mainly because very little selection is evident among dams; if she has a pair of ovaries, she is qualified to be a broodmare).
So you can find plenty of examples to support or negate the theory that dams are more important than sires. I started to write “prove or disprove,” but that would have been wrong. Examples prove nothing. Nevertheless, this is an intriguing area of possible research.
While we are on the subject of American Pharoah, his connections have indicated that he will race again this year. That is good. But it is also the LEAST they can do, considering that he will not race again next year.
There seems to be some sentiment out there that American Pharoah now “has little left to prove.” It is true that he has little left to prove with regard to his own crop, of which he is clearly by far the best.
Secretariat raced quite successfully against older horses after his Triple Crown at three. Seattle Slew and Affirmed both raced at four. Both were champion older horses. Affirmed was Horse of the Year again at four as well. (All three were Horses of the Year at three.)
I suggest that American Pharoah needs to race successfully against older horses (and there are some pretty good older horses out there) before we even start to compare him to the likes of Secretariat, Seattle Slew, and Affirmed. Sadly, I am not optimistic that will actually happen.