The working registries do it differently. I have my working dogs on different types of registries. One is the working sheep dog registry where they dont give a toss what mix the dog is as long as it comes from parents registered on that registry or it satisfies one of the certified stockman that it has good stock working ability when tested. So a kelpie/BC mix on this register will have all the known ancestors on it its pedigree which could stretch back quite a long way and it would also be recognised by the ANKC for eligibility for inclusion on its sporting register with no requirement for sterilisation to compete in its events. As far the registery goes their interest is in preserving working ability.
The working koolie and kelpie registeres will assess dogs and the more known the parentage is the higher the level of registration.