ESTIMATES OF GENETIC-PARAMETERS OF TROTTING PERFORMANCE TRAITS FOR REPEATED ANNUAL RECORDS

The heritability and repeatability of trotting performance traits and genetic and phenotypic correlations among these traits were estimated from repeated annual records of 6934 Finnhorse and 5298 Standardbred t rotters. The number of observations in the two breeds was 19 550 and 1 4 184, respectively. (Co)variance components were obtained with animal model and restricted maximum likelihood (REML) method. The heritabili ty estimates were highest for time traits (0.29 to 0.35) and lowest fo r number of starts (0.08 to 0.10) in the two breeds. The repeatability estimates were high for time traits but only moderate for other trott ing performance traits, suggesting that repeated records improve accur acy in genetic evaluations. The genetic correlations among the perform ance traits, especially between time and money traits, were very high and favourable considering the breeding goals. The phenotypic associat ions were distinctly weaker than the genetic ones.