EFFECT OF THE COW AGE GROUP AND LACTATION STAGE ON THE COUNT OF SOMATIC CELLS IN COW MILK

The aim of the paper was to evaluate the effect of the cow age group and lactation stage on the count of somatic cells in cow milk. The analysis was made based on the breeding documentation of 11359 test yields from cows representing twelve herds in the Kujawy and Pomorze Province. All the animals researched calved for the first time in 2001. The numerical data were verified statistically with the analysis of variance following GLM procedure, considering the effect of the herd, father, sampling month, cow groups (primiparas, multiparas), lactation stage at which the sample was taken. The effect of these factors on basic milking yield and the content of somatic cells were mostly highly significant. It was observed that depending on the milk use length in cows during lactation, the content of somatic cells in milk increased, and the yield of milk, fat and protein decreased.