If Mayfield was so smart, and knew so much about breeding dogs and breeding theory, then why wasn't he more successful as a breeder compared to those he talked about?

None of what he has said is a "fact" ... it's merely "what he says" ...

Jack

PS: A dog born in March of 51 could easily sire a litter in 52 ... and would be 18 months old by September. Could also have been bred to on Heinzl's yard for all we know. Birthdates could be wrong on the papers, etc.