Genetic parameters for longevity and informative value of early indicator traits in Danish show jumping horses

Abstract

The study aim was to investigate the usefulness of different longevity measures in Danish show jumping horses as well as potential early indicator traits for longevity in jumping. The analyses comprised jumping competition data from 9592 horses born during 1981 to 1994, 30,435 young horse records, and their pedigree. Genetic parameters and breeding values were estimated using AI-REML and mixed models including fixed effects of birth year, age at first placing, sex and number of offspring. Four longevity traits were investigated: no. years in competition from first to last entry (NYC), no. active years in competition i.e. only years with a registered start/placing (NAY), NAY plus no. foals carried to term by mares (NAYF), and accumulated lifetime points (LDP) combining longevity and competition success. Longevity defined as NAY was found most useful for the Danish Warmblood. The heritability of NAY was 0.11. Young horse jumping traits had moderate to high genetic correlation with longevity (rg: 0.51–0.74) and highest value as indicator trait among young horse traits (rg×rIA: 0.23–0.44). Conformation had lower informative value for longevity (highest |rg×rIA| was 0.10). Including information of young horse capacity and rideability during jumping in a multivariate analysis increased the accuracy of NAY breeding values of younger horses from 0.32 to 0.49 and increased model predictive ability compared to a univariate longevity evaluation.