Foundation & Outcross
A foundation cat is a cat whose relatives, as far as we know, contributed to the genetic pool only through that particular cat. For example, Bridget, relatives: unknown x unknown, is a foundation cat. Her relatives may have contributed to the genetic pool of other cats but are assumed, not knowing it, that this has not happened; if there is no evidence to the contrary. A foundation cat is basically a single combination of genes to be introduced into other cats in the breed. The foundation cats referred to are those who founded the Maine Coon breed before the foundation book was closed, on the contrary the new foundation cats are those introduced into an already established genetic pool. Putting new foundation blood is a slow and difficult process involving several generations and registries. For example: an F1 foundation cat is a first generation Maine Coon often found occasionally in Maine or neighboring states. ACA has its foundation book open so when a breeder finds a cat that looks like a Maine Coon as standard, he can register it as F1 in ACA. The relationship is not known and the date of birth is only estimated. Sometimes the founding Maine Coon can be found on a farm where his relatives live and his date of birth is known in this case for the F1 cat you will have this information available. Once registered in ACA, the cat is bred with other foundation cats, the puppies that are born are then registered in ACA as F2. ACA records only up to F3 after which the puppies are registered in CFF. CFF does not register pedigree puppies with less than F3. TICA and ACFA register from F4. CFA only records from F5 but cats cannot be shown on shows. Only once the cat is F6 will it be considered a PED cat.
It is the cross between cats of different bloodlines (unrelated). Inbreeding performed for three or four generations typically leads to character fixation, after which further improvement becomes difficult. At this point the health of the line can begin to suffer. Reproductive problems may arise or a weakened immune system may develop. Many breeders therefore find it wise to introduce new blood into the line. This consists of an "outcross crossing"; the cats that will be born will be able to show an improvement in their health and vigor since they are born.
Taken from: Pawpeds