Somatic cell count and milk yield and composition in Black and White x Holstein-Friesian cows

The aim of the research was to evaluate the effect of genetic and environmental factors on milk productivity and quality, and to analyse the relationships between the number of somatic cells and milk traits. Research was carried out on 29.000 cows in the, active population of the Pomeranian and Kuj awy regions. The data included milk yield, composition and somatic cell count from test day records, in complete lactation following calving from June 1998 to May 1999. The analysis indicated the significant influence of somatic cell count, genetic group, age of cow, season and period of lactation on milk yield and composition. There is a highly significant relation between somatic cell count and milk traits - negative for daily yield and lactose content and positive for fat and protein content. Daily milk loss was estimated to be 1 kg per logarithm unit of somatic cells. The findings of this study suggest supporting HF in crossbreeding, which results in an increase in milk yield together with a higher milk fat and protein content. Udder health, however should also be an important consideration.