Bayz

Bayz is a multi-trait random regression model used to estimate the variances, covariances, and correlations between Chinese and Nordic Holstein populations for three milk production traits at different levels of genome region. The method uses latent variables to model heterogeneous variance and covariance and is shown to be comparable to a multi-trait GBLUP for the whole genome as one region. Results suggest that certain chromosomes account for very large genomic variance, covariance, and correlation for milk yield and fat yield. Overall correlations between the two populations are positive and high, but some regions show weakly positive or highly negative genomic correlations for milk yield and fat yield. The estimated genomic parameters can be useful for improving genomic prediction accuracy using a joint reference data in the future.