Implementation and Prospects of Linear Profiling in the Warmblood Horse

Linear traits have been used in animal breeding since the 1970s, but their routine assessment for selection purposes varies among species, breeds, and breeding organizations. Descriptions of trait expressions relative to biological extremes capture more information than valuations of favorability, particularly when combined with higher specificity of trait definitions. Increased objectivity and better comparability of linear than valuation scores have been important arguments for introducing linear traits in the breeding programs of, for example, dairy cattle, where linear conformation traits have become standard components of national and international genetic evaluations. However, refined trait definitions increase the number of traits to be assessed, which may make it infeasible to broadly work with linear traits. Despite significant research activities since the 1980s, few Warmblood studbooks have included linear traits in their breeding programs. As in other species, feasibility issues were the main reason for retardation, but some pioneer work in the field and advances in recording logistics have contributed to recent intensification of linear profiling in several European studbooks. Compromises have been found regarding trait spectra and efforts for linear assessments in a breeding context. Different strategies in pilot and routine applications of equine linear profiling are reviewed with their perspectives for data usage and future developments. Similar focus of studbooks on the competitive and durable riding horse implies options of synergistic progress in the development of comprehensive linear schemes and efficient collection of linear data, providing the basis for better utilization of conformation and performance information in Warmblood breeding.