The foundation of a breeding program is designated F-0. Several animals can have that designation. The first generation is F-1, the second is F-2 and so on. If you breed back to an ancestor, you can have a pretty interesting looking web-- F-O buck over a F-3 doe, a F-2 doe under a F-5 buck, etc....
just remember, if you are breeding to develop a registerable animal from rabbits with unknown ancestry-- using anything with a F number lower than 3 will invalidate the offspring's eligibility. There must be three known generations on the pedigree!!!
Knowing the generation of an ancestor that is being bred back to helps show some people where the qualities that are being enhanced are coming from. It can also show where undesireable traits are coming from.
