Golden Treasure
Golden Treasure
Health, The Purebred Dog and Hybrid Vigour
Health, The Purebred Dog and Hybrid Vigour
Originally, when many breeds were first recognized by the major breed registries, the breed registry was open. A knowledgeable person or show judge would look at a particular dog and decide if the it was a good representation of it's breed. There were no known registries or pedigrees that could accompany it.
For the last 3 or 4 decades the stud books have been closed. Only dogs born of purebred, registered parents have been considered purebred. Which only allows for breeding within a set genetic group.
Many of todays breeds have started with as little as 10 original animals. These have, in the case of some breeds, all been fairly closely related or in some cases all belonging to the same kennel.
There is no ability with the CKC and AKC to introduce new genetic lines unless they have a three or four generation pedigree to accompany them. Geneticists realize that limited populations cannot remain healthy indefinitely without fresh genetic input.
The closed studbook system is subject to what geneticists call "founder effect." This means that a breed population will reflect the genetic input of the limited group that contributed to its breed foundation. Thus if one or more founders out of a group of ten carry a defect normally rare in the overall species population, resulting new breed can easily have a ten percent or greater incidence of that defect.
With the closed studbook system many breeds have health problems or defects that breeders are now vainly trying to eliminate through health testing. It is widely recognized by most people that purebred dogs are less healthy than the genetically diverse "mutt" or crossbred.
Crossbreeding has the opposite effect of inbreeding. It reintroduces a genetic variety creating what geneticists refer to as heterosis or hybrid vigour. Hybrid Vigour is a proven outcome of a healthier, more fertile, and mentally stable offspring.
The farther apart in relation two animals that are mated are, the better! The proper idea of crossbreeding requires that the two parent breeds be complimentary to each other.