class in the dam

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class in the dam, david dink, statistics and breeding

David Dink has a three-part series on class in the dam as a tool in evaluating breeding prospects and mating the critters.

It can be accessed at http://ddink55.wordpress.com/

The statistics are fairly stiff work, but the less mathematically inclined may read the introductions and conclusions to find the majority of useful information Dink has unearthed and reminded us about with this series.

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new blog on thoroughbred breeding

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boojum's bonanza, david dink, statistics and breeding, thoroughbred breeding

There is a briskly written new blog on the net with the enticing name of Boojum’s Bonanza. Visit it here.

Boojum is the pen name for the statistician, theorist, racing historian, and writer David Dink. Long a devotee of independent inquiry, Dink has produced massive studies on the effects of inbreeding and dosage, in particular, that have drawn both high praise and vitriolic condemnation (depending on the individual).

As that suggests, Dink is not a writer inclined to sit upon the fence of fashion and make quiet comments that can be taken in many ways. Instead, he tends to fire at will and let the bodies lie where they fall.

It is an approach to discourse that has its charms.

So I would encourage all the statistically challenged to take a gander at Boojum’s Bonanza and see what an amazingly deep well is there to be sampled. Dink’s general interest, statistics as a means of illuminating pedigrees, is a facet of breeding that is nowadays virtually extinct in print and underrepresented on the net.

The site has, as yet, only freshly minted pieces on Birth Month, Coat Color, and a two-part dissertation on inbreeding to Bold Ruler. That is plenty for a start. Read, think, and ask questions.

inbreeding to northern dancer by the numbers

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apex runners, bill oppenheim, david dink, inbreeding to northern dancer, inbreeding to thoroughbreds, international thoroughbred, mating theories, statistical analysis, thoroughbred breeding, thoroughbred daily news

In an article for Thoroughbred Daily News last Wednesday, Bill Oppenheim fell upon the topic of inbreeding to Northern Dancer and evaluated the practice in terms of his APEX runner database. He studied horses inbred to Northern Dancer in the male line and broodmare sire line

as a percentage of all Northern Dancer-line sired A Runners, by year foaled, 1996-2005. That percentage increased from 13.2 percent among 380 Northern Dancer-line sired A Runners foaled in 1996 to 22.4 percent of the 566 Northern Dancer-line sired A Runners foaled in 2004, and 22.7 percent of the 409 Northern Dancer-line sired A Runners of 2005 (including just three-year-olds by the end of 2008, so the number of 2005-foaled A Runners will have increased significantly by the end of 2009).

Then Oppenheim evaluated the A runners inbred to Northern Dancer as a percentage of all A runners in his database. He wrote: “That percentage has increased from 4.3 percent (50) of the 1,151 A Runners foaled in 1996 to 9.3 percent (127) of the 1,371 A Runners foaled in 2004, and 9.6 percent (93) of the 967 A Runners (through the end of 2008) foaled in 2005.”

Coincidentally, in the current issue of International Thoroughbred, David Dink has authored an article and companion study of 7,206 horses from weanling, yearling, and 2-year-old sales from 1999 through 2002, which is a slightly older population than Oppenheim’s. Dink’s massive study of this moderately elite group (sales horses are better than overall breed norms) yielded 13.28 percent inbred to Northern Dancer through any line in the pedigree. Part 1 of this study, with discussion of the statistics and their implications, is in the current issue of International Thoroughbred, and Part 2 of this study is planned for the next issue of the magazine.

Dink’s study answers one of the questions posed by Oppenheim in his article last week: “Is Northern Dancer over Northern Dancer 9 or 10 percent of the whole population?” From the data mined by Dink, the answer is an unequivocal “yes.”

This is an increasing trend as both of these statistical approaches show, and one of the corollaries to this rising line of incidence is that more and more lesser horses will be mated along these lines, resulting in less success for this type of cross. But importantly, it is an approach that breeders and advisers respond to and consider seriously.

Dink said, “One of the reasons I undertook this study was that when you put statistics in terms of inbreeding, people will pay attention. If, on the other hand, I had evaluated the numbers in terms of positions of horses in pedigrees, they just yawn.”