Avian Production Management

Class, breed, variety and strain

DEFINITION OF CLASS, BREED, VARIETY,  STRAIN AND LINES 

•  Class - Used to designate a group of birds - developed in certain regions or geographical areas. They are American, Asiatic, Mediterranean and English.
• Breed - refers to an established group of birds within a species related by breeding, possessing a distinctive shape, conformation, plumage colour, comb type, general body weight and breeds true. Ex. Aseel, Rhode Island Red, Leghorn, Cornish, etc.
• Variety - used to sub-classify breeds. There may be many varieties within a breed differentiated by plumage colour, pattern and comb type Ex. White Leghorn, Black Leghorn, Brown Leghorn, Barred Plymouth Rock etc.
• Strain - Sub classifications of a breed. Normally a strain is named after the person who has evolved them or it can also be named after the institution where it is developed. They are developed duly giving importance to certain specific traits like egg production, early maturity, better feed efficiency, egg weight etc. Ex. Meyer strain of White Leghorn, Forsgate strain of White Leghorn, Sterling strain of Rhode Island Red.
• Lines - Sub classes of  a strain developed such that the gene(s) responsible for a particular trait is fixed so as to be utilized for production of commercial hybrids.