Structural assessment of the Scottish stratified sheep production system

This paper deals with a new approach of describing Scottish stratified sheep production system using information about the breed/crossbreed structure of 133 flocks surveyed in 2006. The aim was to develop a more accurate tool that could simplify the assessment and description of structural changes of this system. The methodology involves grouping sheep breeds, creating a Flock Type pattern based on the parents breed and the potential outputs that could be carried out in the flocks, and finally stratifying the flocks using a Classification Tree procedure to get an approximation to the traditional hill–upland–lowland description of the system. Scottish stratified sheep production system is described using categorical variables from the survey and a Pearson X2 statistic. The results emphasise that stratified structure is an important part of the Scottish sheep production system, and that stratified management is in turn an important part of the stratified structure. Breed structure, breeding goal and flock replacement changes are explained, and how they are affecting the present system. After comparing the results with other studies, the Scottish sheep production system seems to be moving towards a less dynamic system, with a new balance of breeds, more introductions of Terminal Sire breeds and in which Self Contained breeds and other crossbreeds ewes could compete with mules.