Genetic trends for performance of Swedish Warmblood horses

The main breeding objective for the Swedish Warmblood horse (SWB) is to produce competitive horses in show jumping or dressage. The aims of this study were to investigate the genetic trends of SWB and the factors affecting the genetic progress. The realised genetic trend was studied separately for stallions and mares using the relative breeding values (RBVs) from the official genetic evaluation in 2009. RBVs were estimated using a multi-trait animal model with results from competitions and two young horse performance tests. The genetic progress increased substantially from the mid 1980s in both show jumping and dressage. The improvement rate was almost twice as high for show jumping as for dressage, 0.056 genetic standard deviation units per year compared with 0.032. The trend of broodmares followed the trend of the un-selected mares; thus the achieved progress was solely due to stallion selection. The stronger stallion selection was a result of the improved stallion performance test introduced in late 1970s, import of high quality stallions, and the BLUP evaluation based on the progenies results at young horse performance test introduced in 1986. For stallions born until 1984 the selection intensity was close to zero, thereafter the selection intensities corresponded to selection of the 5% best stallions in show jumping and the 28% best stallions in dressage. Accuracy at selection was 0.60 in show jumping for both stallions and broodmares, and 0.41 and 0.48 in dressage for stallions and broodmares, respectively. The generation interval was 11.1 years for stallions and 10.3 years for broodmares. In the future the breeding programme should focus on more efficient use of RBVs for selection of both stallions and broodmares at both young age and when progenies of stallions have been tested. Because of the strongly increased genetic level in the population, high quality stallions can be selected within the SWB population to a higher extent than previously.