Breeding should be done in an effort to improve the breed. Not only when you breed a litter yourself, also when you offer your dog at stud.
Diploma's don't mean much to me. I'd rather see the dog in the field myself.
Not every dog I've bred shall be used in the breeding programm and a bitch that comes for a mating has to have certain qualities. Multipying isn't very difficult, breeding a good litter is!!!!