Interbreeding
Interbreeding, the process of mating together a Bull Terrier (Miniature) and Bull Terrier, is allowed, only for a short time, in Australia, New Zealand, and the United Kingdom. Interbreeding is undertaken to reduce the incidence of Primary Lens Luxation in the Miniature. The Bull Terrier does not carry the PLL gene so all progeny are phenotypically normal for the disease.
Each country which allows interbreding have their own protocols which govern which dogs can be mated. Australia has no protocols, while the United Kingdom and New Zealand requires strict adherence to health testing and identification of dogs used.
Read more about this topic: Bull Terrier (Miniature)