Is Overbreeding to Native Dancer Responsible For All Of These Breakdowns?

Very interesting article by William Nack on the overbreeding to Native Dancer and how that is causing so many breakdowns in American racehorses. They just may be on to something, so I did some work on pedigree query researching the pedigrees of every high profile breakdown victim of the last few years. Every single one of them had multiple crosses of Native dancer in their pedigree, representing massive inbreeding. It inspired me to take a closer look at pedigree and breakdowns.

On the flip side I did some research on some of our old warriors. The iron horses that have campaigned year after year, virtually injury free. Out of a selection iron horses like Evening Attire, Spooky Mulder, Naughty New Yorker, Broad Brush, Say Florida Sandy and Arromanches only Broad Brush is free of Native Dancer blood so it is very hard to even find a horse out there without the Native Dancer blood. However most of the old warriors are not inbreed to Native Dancer like the tragic breakdown victims Eight Belles, Barbaro, George Washington, Mending Fences, and Pine Island. Most of the old warriors had balanced pedigrees with sound influences like Damascus well represented in the pedigree.

On a similar note there is the offspring of Unbridled and how it relates to Eight Belles. On youtube they have the ABC pre-race coverage of the 1990 Belmont Stakes available for viewing. It it an interesting watch as you can catch a glimpse of the game before drugs like Lasix were legal everywhere. Before the Belmont Stakes the hosts of the coverage openly doubt the favorite Unbridled's ability to race in New York due to the lack of lasix in New York. At the time New York was the only triple crown jurisdiction to restrict the use of lasix. As they hit the 3/8th pole Unbridled spit the bit. Did he spit the bit because he could not race on his anti-bleeding medication? The horses effort was completely unlike his derby triumph 5 weeks earlier when he had the benefit of lasix. Unbridled is of course the Sire of Unbridleds Song who retired unsound early in his three year old season and is the sire of Eight Belles. Could this be a case of a unsound, drug addicted sire passing his unsound genetic DNA to generation after generation?