Genetics and Breeding: Clinical Mastitis in Norwegian Cattle: Frequency, Variance Components, and Genetic Correlation with Protein Yield

摘要

Records of clinical mastitis in first lactation Nor- wegian Cattle from 1978 onward were analyzed. Vari- ance components for clinical mastitis were estimated with a linear sire model using records of more than 1.2 million cows from 2043 sires, resulting in herita- bility estimates of 0.035. Different strategies for ex- tracting data gave very similar results, and estimated heritability for mastitis was the same with univariate and bivariate (with protein yield) analyses, which indicates that selection bias caused by correlated responses from other traits in the breeding goal is not a problem with this data set.