Inbreeding to a Sire in the Female Line
by Roger Lyons
Sid Fernando recently posted on Eskendreya at his Sid Fernando + Observations blog, and he included a link to something he posted on Eskendereya at WTC’s Who’s Hot blog just after the Fountain of Youth, and I went back and read it again. In that earlier post Sid draws a parallel between the pedigrees of Eskendereya and Real Quiet. What do they have in common? Inbreeding to a sire in the female line.
That way of putting it is easier than saying “inbreeding to the sire of a mare in the female line,” which is more accurate. I recall that many years ago David Dink, in his broad study of inbreeding for the Thoroughbred Times, chose the simpler expression, so I’ll use it, too. David did a study so broad that it was almost guaranteed not to find any effects of inbreeding, but, as I recall, he did a special installment on inbreeding to a sire in the female line because it was the only pattern of inbreeding that actually did get results that exceeded opportunity.
Just before re-reading Sid’s post from late February, I had posted some comments on Eskendereya (my last post), among which was the observation that Giant’s Causeway really didn’t have a very good strike rate with Northern Dancer, that he liked Raise a Native a lot more, and that’s true. However, after re-reading Sid’s post, which was about inbreeding to Northern Dancer in the female line of Eskendereya, I checked the numbers for occurrences of Northern Dancer as a sire in the female line of mares that have produced foals by Giant’s Causeway. Sid is going to like what I found.
Giant’s Causeway had 12 mares whose dams were by Northern Dancer–inbred 4×3 to Northern Dancer. The only mare to produce a superior runner was the dam of Aragorn, a dual-G1 winner. The story is high quality, low frequency, but that’s not the end of it.
He sired foals out of 16 mares whose third dams were by Norther Dancer–inbred 4×4 to Northern Dancer. Two of those mares produced superior runners, including G1 winner Frost Giant and Model, a listed stakes winner. It seems fair to assess that provisionally as high quality, average frequency, especially since it’s Eskendereya’s pattern. He won’t be included in my tallies until after the classics.
Giant’s Causeway sired foals out of six mares whose fourth dams were by Northern Dancer–inbred 4×5 to Northern Dancer. Two of those mares produced G1 winners, including Red Giant and Internallyflawless. Unequivocally, that generational distance yielded high quality, high frequency.
Clearly, as far as Giant’s Causeway is concerned, there is something special about mares with Northern Dancer as a sire in the female line, and I wouldn’t be surprised to find that this approach does have broad effects for certain sires, as David Dink’s study found and as is suggested by Sid’s comparison. After all, Raise a Native is the key sire in Real Quiet’s female line. It’s not just a Northern Dancer thing, but generational distance could be a factor, especially in regard to frequency.
Posted by Roger Lyons on Sunday, April 11, 2010 at 3:19 pm.
Pedigree Profile: Eskendereya
by Roger Lyons
The norm in pedigree interpretation is to cite the case of an individual stakes winner and attribute its superiority as a racehorse to any pet theory one likes. One might cite the case of Footstepsinthesand (Giant’s Causeway–Glatisant, by Rainbow Quest), for example, and, in near isolation from other relevant cases, tag linebreeding through Storm Bird and close genetic relative Nijinsky II as a factor. However, that pedigree consultants happen to be selling linebreeding does not make it a reliable norm of pedigree interpretation.
In fact, Giant’s Causeway has sired foals out of 108 mares with Nijinsky II in their ancestries through his 2006 crop, and only six of those mares produced superior runners by him. Even when attempting to account for the superiority of a given runner, it’s important to know the ways in which the breeding of that runner is exceptional, relative to its broader pedigree context. I think it says as much about Giant’s Causeway as anything else I’ve ever seen that Footstepsinthesand’s third dam is by Grey Sovereign, of all things (that great quarter-horse sire line), with which, through females only, Giant’s Causeway has a strike rate of 5/16! And, it explains a lot about Footstepsinthesand, but stay away from the male strains (only 1/35).
It’s quite another thing, then, to cite an individual runner and to assess its breeding from the standpoint of its larger populational and pedigree context. True, that’s what I happen to be selling, but it’s hardly a circumstantial choice. The kind of statistical underpinning required by that approach is not as difficult as weaving a rope of sand, but, if it were easy to come by, everybody would be doing it.
The dam of Eskendereya (Giant’s Causeway–Aldebaran Light, by Seattle Slew) does not have Nijinsky II in her ancestry. If she did, there’s only about a 5% chance that Eskendereya would be one of Giant’s Causeway’s better runners, much less likely favorite for the 2010 Kentucky Derby. The breeding of his dam is, in fact, much more typical of the dams of Giant’s Causeway’s best runners, but not overwhelmingly so. From the standpoint of ancestors that have proven highly favorable to Giant’s Causeway, she ranks at the 48th percentile among the dams of all the foals he’s sired.
The ancestors with which Giant’s Causeway has had very good strike rates don’t tell the story in this case, however. Aldebaran Light is a mare whose profile with Giant’s Causeway is characterized by a cluster of ancestors with which he has had an average rate of stakes production. With Seattle Slew, sire of Aldebaran Light, Giant’s Causeway has a strike rate of 7/75. That’s about as close to his average as an ancestor can be without nailing it exactly.
It’s no secret that Giant’s Causeway prefers Raise a Native to Northern Dancer, but Alydar, sire of Eskendereya’s second dam, has not been a favorite. He much prefers Mr. Prospector. His strike rate with Alydar is 2/34 overall, somewhat below average, but that’s deceptive because both of those superior runners were out of mares to which Alydar descended through female strains, as in this case. Giant’s Causeway’s strike rate with Alydar through female strains is 2/24, right around his average.
Those two runners are indicative. The dam of Pointilliste, winner of multiple stakes in France, including the Prix de Barbeville (G3), is by Alydar and out of a Habitat mare. She won stakes at distances of 12 and 15 furlongs. However, the breeding of Flying Spur, second to Rachel Alexandra in last year’s Fair Grounds Oaks (G2) is more telling. Her dam, Lakeway, is bred on exactly the same sire-line cross as the dam of Eskendereya. She’s by Seattle Slew and out of an Alydar mare.
So, both logically and actually, a cluster of ancestors that yield average frequencies of superior runners for a stallion does not mean you should expect an average runner. Such a profile still means an average rate of production of superior runners. So, it’s hardly surprising that a horse like Eskendereya could result from that kind of profile even though one can’t point to some overwhelmingly favorable factor and say, with warrantable confidence, “That’s why.”
Posted by Roger Lyons on Saturday, April 10, 2010 at 1:37 pm.
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