Estimates of Genetic Parameters for Racing Times of Thoroughbred Horses

Authors: BÜLENT EKİZ, ÖMÜR KOÇAK

Abstract: The aim of this study was to estimate the genetic parameters for racing times, which are needed for a selection program of Thoroughbred horses in Turkey. The racing records used in the study were obtained from the Turkish Jockey Club. The trait used in the study was racing time for racing distances of 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200, and 2400 m. The data from each racing distance were analyzed separately. Genetic parameters were estimated by REML procedure using the DFREML program. Estimates of heritability ranged from 0.177 to 0.353, depending on the racing distance. While estimates of heritability were highest for the 2 shortest distances (1200 and 1300 m), it was lowest for 2400 m, the longest distance. Estimates of pe^2 were lower at shorter distances than at longer distances. Estimates of repeatability varied from 0.289 to 0.404, depending on the racing distance. These results indicated that a moderate level of genetic progress is possible for racing time if selection is based on the phenotypic value of the horses.

Keywords: Thoroughbred horse, racing time, heritability, repeatability

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