Genetic variability of traits recorded during 100-day stationary performance test and inbreeding level in Polish warmblood stallions

The objectives of this study were to estimate direct heritability of 30 conformation and performance traits evaluated during 100-day stationary performance test and to predict the genetic effects in Polish Warmblood stallions. Inbreeding coefficients were estimated as well. Moreover, phenotypic and genetic trends were derived. The data were extracted from the database of the Polish Horse Breeding Association. The analysis included 494 warmblood stallions, which performed during 100-day test in the years 2002-2008 at two Polish Training Centres. Pedigree data comprised 8 512 individuals. Restricted maximum likelihood was employed to estimate parameters under an additive genetic model (including fixed effects: age of stallion, breed, year and place of performance test). Nonzero inbreeding coefficients were estimated for 88 stallions with performance records as well as for 458 unrecorded ancestors. Average inbreeding level for the stallions with records was 0.29 %, whereas for all inbred individuals – 1.69 %. The average completeness of the pedigrees, expressed as Cassell coefficient, for the recorded stallions was 42.47 %. The heritability estimates varied from 0.14 (character) to 0.87 (total index). Relatively high heritabilities were found for jumping-ability traits. In general, the genetic trends for studied traits were negligibly positive.