Clustering the relationship matrix as a supportive tool to maintain genetic diversity in the Scandinavian cold-blooded trotter

ABSTRACT In the joint breeding population of the Norwegian and North-Swedish cold-blooded trotters, formerly suggested actions concerning sire selection strategies due to reduced genetic variation have not been implemented. The aim of this study was therefore to update the status regarding genetic variation and to explore the cluster structure and evaluate if such a tool could give an immediate action to maintain the diversity. This study reports that the joint population is approaching a bottleneck, and clustering of the additive relationship matrix of one year-class showed that some smaller clusters existed, mainly in the Swedish part of the joint population. Through active recruitment of sires in these clusters, there is a potential for maintaining the genetic variation. Development of an interactive mating tool is essential, realizing real-time subscription of mares to sires on basis of knowledge of the cluster structure, which would give an immediate, practical solution close to minimum coancestry mating.