Genetic and environmental correlations among somatic cell counts, milk yield and protein percentage in milking ewes

摘要

A total of 10,624 monthly test day records of SCC, milk yield, and protein percentage for 3,489 Spanish Churra ewes from 10 flocks were used to estimate genetic and environmental correlations. Genetic correlations were estimated by REML procedure with a multitrait repeatability animal model. Genetic correlations of log SCC with milk yield and protein percentage were -0.10 and 0.03, respectively. Genetic correlation between milk yield and protein percentage was -0.27. Permanent environmental correlations of log SCC with milk yield and protein percentage were -0.26 and 0.23, respectively. Phenotypic correlations were -0.15 and 0.10. The low genetic correlation of log SCC with milk yield and the nil genetic correlation between celt counts and proteinpercentage may indicate that selection decisions for improving milk yield and protein percentage for Churra ewes are not expected to have an effective correlated response in cell counts.