Opportunities for joint genetic evaluations of Danish and Swedish sport horses

Viklund¹, Å., Furre², S., Vangen², O. and Philipsson¹, J. ¹Swedish University of Agricultural Sciences, Animal Breeding and Genetics, P.O. Box 7023, S-75007 Uppsala, Sweden; Norwegian University of Life Sciences, Department of Animal and Aquacultural Sciences, P.O. Box 5003, N-1432, Ås, Norway; asa.viklund@slu.se

The Nordic Interstallion project aims at a joint genetic evaluation for the Nordic sport horse populations. The populations use foreign stallions of similar origin to a great extent, but a stallion may have too few offspring in each country for a reliable national breeding value. All Nordic countries should therefore benefit from a joint genetic evaluation. The present study included data from show jumping and dressage competitions in Sweden and Denmark through 2011. Show jumping data consisted of 28,000 and 19,500 competing horses in Sweden (SWB) and Denmark (DW), respectively. For dressage the number of horses was 15,200 SWB and 20,800 DW. Lifetime performance in each discipline was defined as lifetime accumulated points. The joint pedigree file was traced 7 generations back ending up with 174,000 horses. For the competition horses the pedigree completeness index was on average above 80%. In total 1074 stallions had competing offspring in both countries. The genetic similarity (GS) between SWB and DW was calculated to 60%. Both countries contributed almost equally to GS, 52% from SWB and 48% from DW. Genetic analyses were performed with a bivariate animal model with performance in the different countries considered as different traits. The genetic correlations between performances in the two countries were close to unity, 0.99 for show jumping and 0.98 for dressage. Heritabilities for dressage were estimated to 0.23 for both Swedish and Danish data. For show jumping the heritabilities were estimated to 0.34 and 0.30 for Swedish and Danish data, respectively. The high genetic correlations between performance traits, and high GS between the both populations, show that the joint data can be used to estimate common breeding values. Next step in the project is to include competition data from Norway and Finland.