Written By: Ehsan Jahandarpour

A breed is a specific group of domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist several slightly deviating definitions. Breeds are formed through genetic isolation and either natural adaptation to the environment or selective breeding, or a combination of the two. Despite the centrality of the idea of “breeds” to animal husbandry and agriculture, no single, scientifically accepted definition of the term exists. It was shown by set-theoretic means that for the term breed an infinite number of different definitions, which more or less meet the common requirements found in literature, can be given. A breed is therefore not an objective or biolo