Genetic evaluations of the German Sport Horse: Population structure and use of data from foal and mare inspections and performance tests of mares

Abstract. The aim of the study was to characterize the population of the German Sport Horse, a sub-population of the German Riding Horse, in terms of population structure and genetic parameters. Data from 26 490 horses with information from foal inspections (FI; n=17 881), broodmare inspections (BI; n=12 069) and mare performance tests (MPT; n=2 756) from the years 1990-2006 were used for analysis. A total of 21 traits as scored in the three types of performance tests were analysed. Heritability estimates for traits from FIs ranged from 0.24 ± 0.01 (conformation) to 0.50 ± 0.01 (type). For BIs estimates ranged between 0.15 ± 0.02 (forelegs) and 0.50 ± 0.02 (head). Traits evaluated in the MPT showed heritabilities between 0.18 ± 0.02 (rideability) and 0.46 ± 0.02 (trot). Genetic correlations within and across the three tests were all positive. An analysis of the structure of genetic relationships revealed that the population is influenced by different German Riding Horse sub-populations as well as by thor ough breds. The genetic connectedness within the population is of a complex structure and appeared to be sufficient for genetic analyses. Differences between the genetic pa rame ters estimated in this study for the GSH and those used in the national breeding value esti ma tion system are predominantly insignificant. These results confirm that the GSH is both adequately represented in the national system and that the population itself is a rep re sen tative part of the entire German Riding Horse population.