Not sure who wrote this, but it is part of the background on Purim at the Richland Hills website:
PURIM AS A SIRE
Purim goes to stud with the advantage of being a total outcross for the sire lines that dominate the contemporary Thoroughbred population (Northern Dancer, Raise a Native, and Seattle Slew). Further to his advantage, he was produced from a mare that is not bred similarly to those mares which have produced most of the better runners by his sire. Therefore, Purim can breed mares from the sire lines that Dynaformer does the best with, without inbreeding.
Purim is descended from the 1-k family, whose most famous representative is Dr. Fager. This is not surprising since Dynaformer crosses very well with the daughters of Dr. Fager and his sons—particularly Dr. Blum. This is a family that inbreeds to itself very well, so Purim will likely do well with these mares as well. Because Purim resembles his sire a great deal phenotypically, it’s probably safe to assume that he is similar genotypically. Purim arguably had more talent than his sire, achieving grade one status on the racetrack.
Dynaformer offspring are usually very large, somewhat coarse and often late maturing. These traits can be minimized to an extent through selection of mates. Purim has minor inbreedings to Hail to Reason, and to *Ribot. He is bred to be sound on the top and bottom of his pedigree, and displayed that as well. This should be a huge factor in his success as a sire. Dynaformer works with a number of different sire lines, but gets his best runners out of mares from the Native Dancer and Nearctic lines. Of his five best runners, four are from the Native Dancer line. Mr. Prospector and some of his sons have done the best, but some mares from the Nearctic line have done well also.
Daughters of Mr. Prospector have been bred to Dynaformer 11 times, with 4 being superior runners, including Grade 1 winner Film Maker. The daughters of several Mr. Prospector sons have produced poorly when bred to Dynaformer. Mares by Conquistador Cielo have done nothing when bred to Dynaformer—this cross is 0 of 13. Ironically, a daughter of his son Marquetry produced a superior runner when bred to Dynaformer. Gone West daughters have done little to date when bred to Dynaformer—0 of 6. But it is much too early to totally discount some of these numbers as the sample size is still too small to be conclusive. Seeking the Gold mares produced Grade 1 winner Riskaverse from six tries. On the other hand, Dynaformer was bred four times to daughters of Carson City—two stakes winners resulted, one being the best runner by him—Barbaro. Part of this is likely explained by an infusion of speed and smaller size.
The other line of Native Dancer to work well with Dynaformer is Sharpen Up (GB). The daughters of his son Diesis (GB) have crossed repeatedly well with Dynaformer—7 of 15 times. Another son, Cut Throat, has a daughter that produced a superior runner from just two tries. Other representatives of the Native Dancer line to cross well with Dynaformer include daughters of Alysheba (2 of 3), Kingmambo (1 of 1), Thunder Gulch (1 of 1), Saratoga Six (1 of 2), (Miswaki 2 of 8), and Fappiano (1 of 4).
In the future, I think that Dynaformer and his sons will do well with Quiet American mares. Dynaformer is 0 of 1 with them so far, but these mares combine Mr. Prospector with the blood of Dr. Fager. This could be a significant cross. The only drawback is from a commercial standpoint, you are combing lines that are subject to getting coarseness. Other young sires that should make good broodmare sires whose daughters might work well with Purim in the future include Tale of the Cat, Coronado’s Quest, Langfuhr, Chester House, Dixie Union, Cherokee Run, Distorted Humor, Forest Wildcat, Forestry, Giant’s Causeway, Hennessy, Lemon Drop Kid, Smoken Glacken, and Unbridled’s Song.
