1. Institute of Genetics; Vetsuisse Faculty; University of Bern; 3001 Bern Switzerland
2. Department of Clinical Veterinary Medicine; Swiss Institute of Equine Medicine; Vetsuisse Faculty; University of Bern, and Agroscope; Länggassstrasse 124 3012 Bern Switzerland
3. Swiss National Stud Farm; Agroscope; 1580 Avenches Switzerland
4. Department of Animal Sciences; Functional Breeding Group; Georg-August University Göttingen; Burckhardtweg 2 37077 Göttingen Germany
5. Institute of Animal Breeding and Husbandry; Christian-Albrechts University Kiel; Hermann-Rodewald-Strasse 6 24098 Kiel Germany