"The truth of the matter, it appears to me, is that there is very little difference between the overall results of inbreeding (within five generations) and the overall results of NOT inbreeding (ditto)."

"... the lesson from these big, beautiful, and brilliant performers is that, just as they dominated on the racetrack, the top racemares succeed more often than the norm in their role as mothers to the next generation of racing stars."

A history of gray thoroughbreds and how the color survived. "We have now reached the wild frontier of the pre-Stud Book era, when a riot of exotic colors like palomino, dun, and buckskin were well attested, alongside our more familiar hues. Gray was on its way to becoming a 'museum' color too. But the thin gray line was preserved, thanks to the otherwise obscure Master Robert, whose gray posterity held on, one generation at a time, until bursting forth anew with The Tetrarch and his tribe. The vicissitudes of genetics, bad advice, sterility, and U-boats could not prevent it."

Re: the first matings of Rachel Alexandra and Zenyatta: "Never before in modern times have the careers of two female racehorses overshadowed male contemporaries for consecutive years. And chances are, any success by their offspring will be attributed to the mares’ genetic prowess while the failures will surely fall on the backs of the sires. That in itself constitutes a seismic shift in attitude."

"The results have varied from the expected (graded stakes winners are the best prospects for producing high-quality runners) to the surprising (fast maiden winners produce a surprising percentage of high-quality runners). We also discuss listed stakes winners as producers (they appear to be over-valued and overbred by breeders), and non-winning mares (it’s hard to justify having them in a high-quality broodmare band), and six other categories of racing class as well."

"In the horsey world, this is huge news. Zenyatta is perhaps the greatest mare ever to have raced. Her pregnancy, if it comes, will likely be the most closely-followed in Thoroughbred history. And the resulting foal, if it comes, will be the most famous weanling ever. If you think Prince William was cute as a boy, and I know you do, just wait until you see this little one running around a paddock in Kentucky in a few years."

"Sixteen foals have been produced by previous matings of animals acclaimed as Horses of the Year, with four of those foals becoming stakes winners and one, Apalachee (Round Table–Moccasin) becoming a champion. That is not a bad strike rate, but the odds are still long against Rachel Alexandra’s first foal living up to its parents’ class."

Handicapping site from Steve Davidowitz and Lauren Stich.

Quick reference on top sires across the board.

Under-the-radar debut sires