[QUOTE=Flying Fox;7716937]
I think there is an important genetic principle here that is familiar to agricultural breeders of plant and animal livestock, but much less so to racehorse breeders.
A broodmare with many exceptional genes may have been thwarted from racing by just a few negative genes–which in turn might be bred out a generation later with an appropriate mate. So a mare with a few racing problems MIGHT nevertheless be a great broodmare prospect. A mare with foot or breathing problems as a racehorse might be mated with a stallion very strong in those areas, with very positive results…
Or, a mediocre racemare may have a genetic make-up that combines extraordinarily well with one or more male lines, so that the offspring exceed the parents in performance. This is very well known to plant and livestock breeders. A very ordinary strain of red flowers might combine with an equally ordinary blue strain, producing an extraordinary strain of purple flowers. *But these purple flowers (hybrids) will not reproduce consistently well themselves, while their modest red and blue ancestors will continue to produce great offspring… Historically we have a good picture of what makes a great broodmare. If we are to put this knowledge to practical use we must look to identify the great broodmare prospects of the future. While pedigrees filled with names like War Admiral, and Sir Galahad III distinguished the best broodmares of the past, we might look for the names of Buckpasser, Hoist the Flag, Graustark, Nijinsky II, Alydar, Secretariat, and Dr. Fager to play a prominent role in the future. All are outstanding broodmare-sires whose pedigrees are filled with strong female influences: top broodmares and broodmare-sires… http://broodmaresinc.com/clustermares/[/QUOTE]
The big difference between breeding plants experimentally and racehorses is cost. I don’t think that TB breeders are unware of genetic principles. But of necessity, they are also very much aware that every experimental breeding costs thousands of dollars and yields one result (if you’re lucky) which will then cost more thousands more (not to mention several years) before its success or failure can be proven on the track. Which is why TB breeders prefer to narrow the variables as much as possible before starting out.
As for the stallions to look for in mares of the future, those are hardly uncommon names to find in TB pedigrees. I’d be willing to bet that at least one of those horses, if not more, appears in the pedigree of 90% of the broodmares in Kentucky. So yes, there are broodmares with those stallions in their families who will produce successful offspring. There are also mares related to those stallions who will produce nothing but duds.