The cold-blooded trotting horse has been successfully bred for trotting performance. At the same time, the intensive selection and use of popular stallions has led to a rapid increase in relatedness within the breed. This implies a risk that inbreeding depression may affect important characteristics. The purpose of this project is therefore to provide a basis for sustainable breeding that promotes the breed's future health and robustness.
The research project started at the beginning of 2024 and is a Swedish-Norwegian collaboration between researchers at the Swedish University of Agricultural Sciences (SLU) and the Norwegian University of Life Sciences (NMBU). The project is conducted in close collaboration with the breeding organizations in both countries. The project will also be monitored by a reference group appointed by the Swedish-Norwegian Foundation for Equine Research and the Swedish Trotting Association.
Photo: Susanne Eriksson
In the project, pedigree information and trait data from both the Swedish and the Norwegian Trotting Associations and Norsk Hestesenter will be analyzed. With the help of statistical analyses, we will study the general effects of inbreeding on different traits in the horses. We will also study whether there are differences between different popular stallions, so-called "matadors", regarding the effect of inbreeding on these individuals.
In addition to the analyzes based on relationships estimated from pedigree information, we also plan to analyze DNA from several hundred hair samples. It provides a deeper insight into the level of relatedness, inbreeding and the possible presence of harmful genetic variants in the breed.
The Coldblooded trotter is one of the native horse breeds for which Sweden (and Norway) have conservation responsibility. Previous studies have shown that strong inbreeding has negative effects on both health, fertility and performance in the breed, but updated information based on the current situation is needed. An important part of the project is to advise on strategies for sustainable breeding based on the results that the project provides.
