Correlations Between Production Traits in First Lactation Holstein Cows

Abstract

Genetic and phenotypic correlations between milk yield, fat (yield and percent, protein (yield and percent), and somatic cell count in first lactation Holstein cows were estimated using a multivariate restricted maximum likelihood algorithm. There were 18,189 daughters of 257 sires in 928 herds. Genetic correlations between pairs of yield traits were all positive (.73 to .88), but phenotypic correlations with somatic cell count were small and negative. Genetic correlations between somatic cell count, and fat percent, and protein percent were negative, −.11. Milk yield, fat yield, and protein yield had heritabilities of .36, .38, and .25. © 1987, American Dairy Science Association. All rights reserved.