Estimation of genetic parameters in land sheep breeds

The objective of the present study was a genetic statistical analysis of performance traits recorded at the day of licensing in land sheep breeds. The performance traits score for muscle mass, type and wool quality were analysed for the breeds German Polled Heath, German Grey Heath, Bentheim, German White Heath and Coburg from breeding regions in Lower Saxony and Westphalia. Systematic fixed effects of herd-year-season, test day, sex, birth rearing type and the linear covariate age at licensing were included in the statistical models to estimate the variance and covariance components. There were high additive genetic correlations between muscle mass and type. The estimates of additive genetic correlations between wool quality and type or wool quality and muscle mass were moderate. The heritabilities estimated separately for each breed ranged between h(2)=0.06 and h(2)=0.16 for muscle mass and between h(2)=0.04 and h(2)=0.09 for type. The biggest range of heritabilities was estimated for wool quality with h(2)=0.03 to h(2)=0.14.