Genetic parameters and breeding values for the South African warmblood horse population

Abstract

1. The aim of this study was to determine the genetic parameters and breeding values for the South African Warmblood horse population. Information collected by the Society from 1989 to 1998 was provided for 2143 horses. This information included bloodline, breeder, owner, gender, birth date, pedigree, and scores from the inspection test. 2. Non-genetic factors that had a significant effect were determined for all inspection test traits. Year of inspection was significant for most traits; gender, breeder, owner, category of age at inspection, year of birth, month of birth, month of inspection and the combined effects of bloodline and register were all significant for various traits. 3. The parameters calculated were the environmental and genetic variance, the environmental and genetic correlations and the heritability. The environmental variance ranged from 0.212 to 1.038, and the genetic variance ranged from 0.014 to 0.137. Environmental correlations ranged from 0.012 to 0.924, and genetic correlations ranged from -0.331 to 0.997. Heritability estimates ranged from 0.009 to 0.374. 4. Best linear unbiased estimates were calculated for the independent variables in the traits for which they were significant. Best linear unbiased predictions were calculated for all animals in the population. Genetic trends were graphically presented for the total scores of the inspection test. Positive genetic trend was indicated.