(Sarah of the Clue Crew reports from an AKC dog show with a new puppy friend.)  According to the American Kennel Club, only the offspring of a sire and a dam of the same unmixed breed qualifies as this
There was not a dog living, according to writers of the eighteenth century, that 
... are well-known facts, but these are mules and will breed only with the parent 
...... A puppy has a small stomach, and what it gets from its dam is very rich food.