All the well-known breeds of dogs are highly artificial and their maintenance requires the constant care of the breeder in mating, and in rejecting aberrant progeny.
The lopeared breed is the oldest English variety, and has been cultivated carefully since about 1785, the aim of the breeder being directed to the development of the size of the ears, and with such success that they sometimes measure more than 23 in.
As the breeder selects a congenital variation which suits his requirements, and by breeding from the animals (or plants) exhibiting that variation obtains a new breed specially characterized by that variation, so in nature is there a selection amongst all the congenital variations of each generation of a species.
Bakewell's fame as a breeder was for a time enhanced by the improvement which he effected on the Long-horned cattle, then the prevailing breed of the midland counties of England.
The sow is a prolific breeder and good mother, weighing, when mature but not fat, 450 lb - the boar averaging 600 lb, and barrows at six to eight months 350 lb.