A survey on the somatic cell count (SCC), fat, protein, lactose and total solids percentages on bulk tank milk samples, from December 1996to July 1998, was used to characterize the milk composition as determined by SCC. Data of 4785 from the database were classified according to the SCC, in four groups (Group 1, SCC < 500 thousand cells/mL; Group 2, 500 < SCC < 1.000 thousand cells/mL; Group 3, 1.000 < SCC < 1.500 thousand cells/mL; Group 4, SCC > 1.500 thousand cells/mL). A descriptive statistics, analysis of variance and multiple mean tests were applied to the groups. Increases on the group classes were associated with increases on concentration and standard deviation and decreases on protein and lactose concentrations. Despite of the no significance, the total solids tended to decrease as group classes increase. The bulk tank milk samples with higher SCC had greater fat percentages, lower protein and lactose percentages and the same total solids percentages. The significant changes in the milk component contents occur above 1.000.000 cells/ml for fat and 500 thousand cells/ml for protein and lactose. Bulk tank groups with greater SCC have greater variability in milk component compositions.
SCC; milk composition; milk tank
