Measuring Dam Lines
by Roger Lyons
Every few years, around November sale time, I survey female lines to see how their rankings have shifted over time. The terms “survey” and “ranking” require definition. This time round, I pulled out the winners of stakes, as compiled by WTC, that were run from 1995 to the present and tabulated every occurrence of every dam in the female lines of these SWs going back seven generations, along with the generational distance of each occurrence.
Then I crunched the numbers as usual to find out for each dam 1) how many SWs were descended from her and 2) the average generational distance of her occurrence in the female lines of those SWs. That’s all you need in order to get a rough idea of relative contemporary influence because, if you divide the number of SWs by the average generational distance at which the dam occurred in the female lines, then you end up with an index that you can use to rank the dams in a more or less valid way–based on the number of SWs per average number of generations removed. Let’s call it the Dam Line Index (DLI).
For example, La Troienne, which ranks highest among the 70,659 individual dams represented, occurs in the female line (within seven generations) of 298 SWs (since 1995) at an average of 6.42 generational removes. That means her DLI is 298 / 6.42 = 46.42, which is the number of SWs descended from her per generation.
The average generational distance is useful because it controls to some extent for the differential opportunity of mares of different eras. Best in Show, for example, which ranks 10th, occurred in the female lines of 78 SWs and at an average generational distance of only 3.79 generations. So, the index of her influence is 20.58 SWs per generation. That’s a lot less than La Troienne, but not that much less than Escutcheon, which has the second-highest rank, at 28.21 and an average generational distance of 6.38.
Now, there’s always going to be someone who says (without thinking) that seven generations is not enough since La Troienne occurs beyond the seventh generation of some contemporary SWs. That is an untenable position, though, because, if you extend that rationale across the population of dams (not just La Troienne), there can be no generational limit that will satisfy them all.
Besides, the method already has an inherent bias in favor of the older dams. Consider that Urban Sea, dam of sires Galileo and Sea the Stars, plus other high-class sons and daughters, ranks last (362nd) among dams with a DLI of at least 7.0. She is the dam of seven SWs, but has not had the advantage of subsequent generations through which to multiply her influence. She’s almost certainly bound to be better as a tail-female influence than she ranks now, and increasing the maximum generational distance of the survey would only serve to exaggerate the bias against her.
Click here to view the alphabetical list of top-40 dam lines and here to view the same list in rank order.
More about this topic in subsequent posts.
Posted by Roger Lyons on Wednesday, October 20, 2010 at 9:20 am.
Odysseus/Devil May Care, Take Two
by Roger Lyons
In a recent post about the breeding of Odysseus and Devil May Care, I argued that Odysseus is not bred to win a major stakes beyond 8.5 furlongs, as Devil May Care had just done. So, you can imagine how eagerly I anticipated Odysseus’ start in the Bluegrass Stakes (G1). Or perhaps, instead, you imagine trepidation. Either way, I was looking forward to it.
I didn’t expect him to win, but didn’t expect him to run last, either. Then came the sad news of the bone chip, which might well have happened during the race. As so often happens in racing, some questions never find ultimate answers, but that misfortune pales by comparison with the bad luck for Padua Stables, and I’d rather have been proven wrong than have it turn out that way.
In any event, my quarrel with his pedigree has largely, but not exclusively, to do with his close inbreeding to Mr. Prospector (3×3), based on Malibu Moon’s past success and opportunity. Statistical information like that only tells you what to expect based on a norm. Strictly speaking, you can only hypothesize. You can say something like this: if Odysseus is able to win a major stakes at 10 furlongs, then he is not at all typical of his breeding. Any given horse can become an exception to its breeding, but most don’t.
In that same post I also argued that Devil May Care is much more likely than Odysseus to be exceptional relative to the past performance of Malibu Moon’s Mr. Prospector inbreds. First of all, her inbreeding to Mr. Prospector is at 3×4, which is a huge difference. Secondly, she comes from the Roberto sire line, with which Malibu Moon has had good success from opportunity.
Of Malibu Moon’s five SWs inbred to Mr. Prospector, Devil May Care’s breeding is exceptional, especially in regard to her pattern of inbreeding to Mr. Prospector, and readers of my last post (if there are any) might guess exactly how. Odysseus’ dam is by Conquistador Cielo, by Mr. Prospector, which means Mr. Prospector is returned by the sire line of the dam. Devil May Care, on the other hand, is out of a mare whose second dam is by Mr. Prospector. That is to say, Devil May Care is inbred to a sire in the female line–the pattern shared by Eskendereya (inbred 4×4 to Northern Dancer) and Real Quiet (inbred 4×3 to Raise a Native).
The numbers are important. Of all the foals Malibu Moon has sired out of mares in some descent of Mr. Prospector, only five mares had Mr. Prospector as a sire in the female line. Two of those mares had foals inbred at a distance of 3×3. Throw those out because it’s too close. The foals of only three of those five mares were inbred at the much more effective distance of 3×4, like Devil May Care. So, Devil May Care comes from precious little legitimate opportunity.
We don’t know what is typical for that kind of breeding. It’s a new thing for Malibu Moon. Devil May Care has already gone farther in a major stakes than any other of Malibu Moon’s Mr. Prospector inbreds when she won the nine-furlong Bonnie Miss S. (G2). She’s done enough already, but, if she wins the Oaks, her pedigree is the new take on how to get a very high-class Malibu Moon runner inbred to Mr. Prospector.
Posted by Roger Lyons on Thursday, April 15, 2010 at 11:30 am.
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