Best Dam Lines Dominate Derby
by Roger Lyons
Even if I have to say so myself (and I do), the Dam Line Index (DLI) profiles presented in my pre-Derby post were very lucky in separating the contenders from the pretenders. That post cited 11 Derby qualifiers whose DLI profiles, while not necessarily distinguishable from one another, were clearly superior to the rest of the field. Five of those 11–Animal Kingdom, Nehro, Mucho Macho Man, Shackleford, and Master of Hounds–finished in that order. Furthermore, nine of the top 12 finishers were among those 11 with superior DLI profiles. As I recall, even during its glory years, dosage had a lot nearer misses than that.
Of course, the profiles would be more satisfying if, like the individual indexes that constitute them, they would do a better job of ranking the female lines, on the whole. But, how do you compare the profile of Animal Kindom’s dam line, which consists of individual DILs ranging from 4.0 to almost 5.0 for the third through the seventh dams, with Nehro, whose indexes of 1.0 to 3.0 for the first through the third dams lead back to a fourth dam whose DLI is 13.5?
If we had known that on this occasion consistency across the dam line would be better than a big number in the background (and who’s to say it’s not!), then Jackie and I might have taken Animal Kindom on top of Nehro, instead of the other way around–and hit the super!
Posted by Roger Lyons on Monday, May 9, 2011 at 12:16 pm.
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Kentucky Derby Dam Line Index Profiles
by Roger Lyons
The table introduced by this post lists the Dam Line Index (DLI) for the first seven dams of each of the 20 Kentucky Derby 2011 qualifiers. The DLI, remember, is derived from the number of runners winning stakes during the last 15 years and descending, tail-female, from a given dam, divided by the average number of generations that dam was removed in those cases. So, the DLI is, literally, the number of SWs attributable to a dam per generation removed, on average.
The DLI is a pedigree measure and bears only a statistical (read tenuous) relation to performance. What I mean is, you can go very far wrong predicting individual performance based on population characteristics.
There is very little in the DLIs for Uncle Mo’s female line to suggest that he would be Champion Juvenile Colt, let alone a Kentucky Derby winner. What it might suggest, however, is that he is in that respect anomalous to his breeding since, in fact, those accomplishments are largely reserved for horses from better dam lines.
The DLI profiles of Animal Kingdom, Archarcharch, Brilliant Speed, Master of Hounds, Midnight Interlude, Mucho Macho Man, Nehro, Pants on Fire, Shackleford, Soldat, and Stay Thirsty are far more typical of the horses of highest racing class.
Archarcharch has an especially unusual and intriguing profile. Ordinarily, the DLIs in a good female line descend in value from the seventh dam to the first dam, as in the well defined case of Pants on Fire, for example. By contrast, the DLIs in Archarcharch’s female line actually ascend in value from back to front, such that his second dam, Pattern Step (1985), by Nureyev, has a DLI of 5.0, the highest-rated second dam, by far, in the list. This would seem to be the picture of an improving branch of a female line that has otherwise gone more or less dormant.
In any event, see what you can make of the DLI record, but don’t bet on it.
Posted by Roger Lyons on Thursday, May 5, 2011 at 7:33 am.
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