Genetic and phenotypic parameter estimates for growth and carcass value traits of sheep

Heritability coefficients as well as genetic and phenotypic correlations of growth and carcass value traits were estimated for German Mutton Merino (GMM), German Longwool Merino (GLM) and Merinoland (ML) using data From test stations recorded between 1990 and 1996. According to the regulations in German sheep breeding performance testing starts with an average weight of 20 kg and ends at a target slaughter weight of about 42 kg involving only male lambs. Traits analysed were preadjusted for the effects of birth type, recording year, season, flock, contemporary group and age of lamb at measurement. With slight differences among the three involved stations/breeds heritability for traits of growth intensity ranged from 0.22 to 0.47 and was always lowest for pre testing daily weight gain (DGB) and highest for daily gain in the testing period (DGT). Due to maternal influences only low or no genetic correlations between DGB and both other traits were found (-0.14 up to 0.38). There were close relations between daily gain from birth to slaughter and DGT (0.94 - 0.96). The subjective score for conformation shows considerably lower heritabilities ranging from 0.12 to 0.19 for GMM and GLM whereas for ML the estimated heritabilities between 0.43 to 0.47 ranged.