The bloodline or pedigree is a history & map of how the genes express themselves. Objective study will offer improved odds in reaching desired results. The problem with looking at the individual dog is that it may have been the only proper & healthy one from a litter. Further, traits do skip generations. Females may produce puppys that carry thier fathers type vs. the sire of the litter's type. Something that looking at the bloodline will give clues to. Better to concider a breeding prospect from a litter of consistant type dogs vs. the one single good example of a breed. Another concideration is how much temperment & working ablity is breed in vs. put-on my the handler? Again somethging that is hard to deterime by only looking ast one dog.