Inbreeding is when two closely related animals are mated for 4-6 generations.
Out-crossing is when two unrelated animals of the same breed are mated for 4-6 generations.
Cross-breeding is when two animals of two different breeds are mated (e.g. Hisardale).
Interspecific hybridisation is when two animals of two different related species are mated (e.g. Mule).