Historical Review of the Stratified British Sheep Production System

抄録

The stratified British sheep production system is a three-tier production system that includes the hill, the upland, and the lowland subsystems. In the hills, pure-breed ewes are kept, and draft five-year ewes are brought down to the uplands where they can still have a couple of years of productive life. In the uplands, the hill ewes are mated with an upland sire. This first cross brings together hardiness, and mothering abilities to produce dams of the Prime Lamb. These are brought further down to the Lowlands where they are mated to a Terminal Sire to produce the Prime Lamb. The system takes advantage of maternal and individual heterosis and complementarity of breeds. The system marked the British sheep industry of the 20^th century, however, the new challenges faced by the industry may end this unique production system. The objective of this revision is to construct a single document easily accessible to scholars explaining the Stratified British Sheep Production System.