Livestock species are divided into genetic groups called
breeds. Unfortunately, a clear definition of the term breed
is difficult to find. Breed might be dehned as a group of
animals with similar physical characteristics (such as
color, homs, body type, etc). However, there are breeds
that contain wide variation in such raits, while some
breeds may share many characteristics. There is general
agreement that the concept of a breed denotes common
ancestry- However, some breed organizations choose to
allow entry of animals from other breeds. An early
observation was made about the definition of breed:l I I "A
breed is a group of domesdc animals, termed. such by
coffrmon consent of the brceders, a terrn which arose
among breeders of livestock, created one might say for
their own use, and no one is warranted in assigning to this
word a scientific definition and in calling the breeders
wrong when they deviated from the formulated definition.
It is their word and the breeders' common usage is what
we must accept as the correct definition." A breed has
also been described as something that arises more rapidly
than normal evolutionary processes would allow but more
slowly than would be true in rhe laboratory.t'l Sorn"
trreeds arise almost entirely through natural forces,
whereas others arc developed by human managers in a
highly directed fashion. The tolal number of recognized
breeds is probably in excess of 1000 worldwide, although
some are just national derivatives of the same breed.t3]
Several hundred of these breeds are illustrated in the
Breeds of Livestock website maintained by the Department
of Animal Science at Oklahoma State University
(www.ansi.okstate.edurbreeds). Numerous breeds have
also been described in other venues.{o'5]