S. Korver

Stationary performance testing of stallions from the Dutch Warmblood riding horse population. 1. Estimated genetic parameters of scored traits and the genetic relation with dressage and jumping competition from offspring of breeding stallions

Abstract The stationary performance testing (SPT) of stallions as breeding candidates in the Dutch Warmblood riding horse population is evaluated. Genetic and phenotypic parameters of traits scored during SPT and the genetic correlation of these traits with performances in dressage and jumping competition from offspring of breeding stallions are estimated. Data from 1978–1988 are used, covering scores from 337 3-year-old stallions. Eight subjectively scored traits are considered. These traits are: walk; trot; canter; riding ability; show jumping; free jumping; cross country; character. SPT lasts for a period of 100 days. Data from SPT are analysed using an animal model. The relations between SPT of stallions and performances in jumping and dressage competition are analysed with an animal model for SPT data and a sire model for competition data. Variance and covariance components are estimated by restricted maximum likelihood (REML) procedures. Estimates of heritability are high (0.64) for gaits and riding ability, intermediate (0.41) for cross country and medium-high (0.31) for jumping. Estimated genetic correlation between show jumping scored during SPT and jumping in competition from offspring of breeding stallions is 0.84; for dressage this relation is 0.83. Some possible bias due to selection and the subjectivity of scoring is discussed. It is indicated that selection on SPT of stallions before entering breeding service is an effective tool to breed for ability of performance in competition.

Breeding for veal and beef production in Dutch Red and White cattle

Abstract A field trial was conducted to determine genetic parameters in veal and beef production, relationships between performance test and progeny test, and effects of performance and progeny testing on the returns from selection. Progeny of 61 performance-tested Dutch Red and White (DRW) bulls were fattened for veal and for beef. Heritabilities in veal and beef production traits varied from 0.09 to 0.30 and 0.08 to 0.48, respectively. Genetic correlations between corresponding traits in veal and beef production varied from 0.50 to 0.79. Genetic correlations between performance and progeny test were for daily gain 0.58 and 0.66 and for fleshiness 0.18 and 0.37, in veal and beef production, respectively. Effects of selection on performance test data and progeny data (traits of young calves and carcass traits of veal calves and beef bulls at slaughter) were compared. Selection for veal and beef production based on carcass data or based on performance test and carcass data yielded the highest returns. Selection for veal and beef production based on traits of young calves was less worthwhile.