A breeder is a person who practices the vocation of mating carefully selected specimens of the same breed to reproduce specific, consistently replicable qualities and characteristics.

Dog breeding is the practice of mating selected specimens with the intent to maintain or produce specific qualities and characteristics.

A cat breed is an infrasubspecific rank for the classification of domestic cats. A cat is considered to be of a certain cat breed if it is true breeding for the traits that define that breed.

Horse breeding refers to reproduction in horses, and particularly the human-directed process of selective breeding of animals, particularly purebred horses of a given breed.