there seemed to be a little confusion here regarding stud book numbers. you earn your stud book number through champion shows, just because the dog doesnt have its stud book number doesnt mean it is un worthy breeding stock. some perfect breed standard dogs go to pet homes and later have a litter so long as they are health checked and up to standard and a good example of the breed and are line bred i see no problem as you can check how closely related they are via kc papers and pedigrees.
not wanting to cause any arguments just clearing up

also some dogs with stud book numbers arnt necissarily the best dogs to use.