Original sentence: Hybrids between different species within the same genus are sometimes known as interspecific hybrids or crosses.Hybrids between different sub-species within a species are known as intra-specific hybrids.In biology, the word hybrid has two meanings.In less technical conversation (and particularly in the dog world) the word hybrid refers to selective breed crosses and their progeny, even if outcrossed to other breeds.In some dog sports, particularly Flyball, hybrids have become very popular.The Borderjack (Border Collie/Jack Russell Terrier) is desirable because it retains the small size of the Jack Russell but has the athletic ability and trainability of the Border Collie.The Borderstaffy (Border Collie/Staffordshire Bull Terrier) is prized because it has the speed of a Border Collie and the strength of a Staffordshire Bull Terrier.The cross-breeding of dogs is closest to the latter.The first meaning is the result of interbreeding between two animals or plants of different taxa.The second meaning of "hybrid" is crosses between populations, breeds or cultivars of a single species.This second meaning is often used in plant and animal breeding
Edited sentence: Animal rescuers, and other animal lovers, believe that breeding so-called "designer dogs" is both tragic and cruel as long as thousands of mixed breed dogs are left homeless and to die in shelters every day.In the dog world the word hybrid refers to selective breed crosses and their progeny, even if outcrossed to other breeds