Pure breed, Half-breed and Mongrel street dogs,
    What’s the difference?

1. Well, let’s define first what pure breed means.
    A pure breed dog is the product of crossing between two canines of the same breed, recognized by FCI (Fédération Cynologique Internationale). The representative organism of FCI and affiliated in Brazil is CBKC (Confederação Brasileira de Cinofilia).

2. Now we’re going to define Half-breed.
    A half-breed dog is the product of crossing between two canines of different breed. From then on, the product of any crossing of a pure-breed with a half-breed will be, automatically a half-breed.

3. Afterwards, we’re going to define Mongrel street dogs.
    A Mongrel street dog is a product of crossing between two half-breeds whose result makes it impossible to define what breed originated it... Some authors yet define UB (undefined breed) the mongrel whose origin breeds are impossible to be defined.
   
4. Finally we’re going to define UB
    An UB is a dog whose breed, although already spread, was not officially recognized by FCI as a pure breed yet. It is the case of Pitbull, American Bulldog, Brazilian Mastiff, Pampas Elkhound, Brazilian Little Bulldog and the Brazilian Greyhound.