The Northern Dancer effect

Old friend Bill Oppenheim penned one of his most interesting articles in years in the January 6 issue of Thoroughbred Daily News. If you don't subscribe to TDN, that article is behind their pay wall, so I can't help you there.

The theme of the story was Bill's take on the changes in the industry both in the U.S., where he started out and in England, where he now resides (well, Scotland actually) in the last 20 years or so. It's a wide-ranging piece and a very good read that covers the main points pretty accurately and succinctly, with good stuff on the changes in the way people buy horses, the decline of female families as related to owner-breeders, why Europeans don't trust American catalogs, and more.

The most interesting part of the article for this old curmudgeon, however, was the section on inbreeding to Northern Dancer. You'll have to learn about Bill's system of rating runners and sires on your own, but the interesting thing to a pedigree maven is that Bill found that the percentage of his "A runners" (perhaps roughly equivalent to listed winners and above) inbred (though only through sire and broodmare sire lines) to Northern Dancer increased from 4.3% of "A runners" foaled in 1996 to 9.6% of "A runners" foaled in 2005. In other words, about 10% of these elite runners are now by Northern Dancer line horses out of mares by Northern Dancer line horses. But note that he's not counting any other occurrences of Northern Dancer on either the top or the bottom of the pedigree, so, no doubt, he's missing a substantial number of Northern Dancer crosses.

Bill rightly notes all the appropriate caveats about this number, and I'm here to tell you that I have no doubt whatsoever that this represents a serious underestimate of the percentage of horses actually inbred to Northern Dancer among his "A runner" population.

For the racing year of 2008 (the last year Bill's data covered), I kept certain data on every Graded stakes winner in the United States in a spreadsheet, including all inbreedings within the first six generations. 36.5% of them were inbred to Northern Dancer. If I'm not mistaken, Bill's data covers North American racing plus racing in the five major European countries, whereas, as mentioned, my spreadsheet covered only U.S. (not including Canada) racing.

Now here's the thing....Northern Dancer is far, far more widespread in Europe--particularly England and Ireland--than he is currently in the U.S. The son of Nearctic so thoroughly dominates European racing that over half (71 of 140) of the stallions currently listed in Weatherby's stallion book are Northern Dancer line stallions....and most of the non-Northern Dancer line horses will have at least one cross of Northern Dancer on the bottom side.

By contrast, of the 501 horses listed in the Thoroughbred Times online Stallion directory, 162, or 32.4% are from the Northern Dancer male line. That's just one illustration of how much more dominant Northern Dancer is in Europe than in the U.S., but it helps explain why I'm so certain Bill's figures on inbreeding to Northern Dancer are much too low. If the percentage of graded winners in the U.S. inbred to Northern Dancer is somewhere around 35% (and rising, by the way) then it simply has to be higher than that in Europe where Northern Dancer has been totally dominant for the last 20 years. The last time a horse from a male line other than Northern Dancer led the English sire list was 1989 when Blushing Groom topped the list. As we've been discussing this week, exactly how many times which sire line topped the North American list is a vexed question at best, but no matter how you count it, Northern Dancers have stood at the top no more than half the time over that 20 year span.

Now, let's be clear. Neither Bill nor I are complaining about inbreeding to Northern Dancer. It's very clearly a good thing. As Vuillier pointed out over 100 years ago, the best horses (graded stakes winners in this case) of the present basically predict the pedigrees of the future because they're the ones that get the best chance to breed on. So obviously the future of the breed is inbreeding to Northern Dancer.

Those who don't like it can try to avoid it if they wish...at their own cost.