RELATIONSHIP BETWEEN SOMATIC CELL COUNTS AND COMPOSITION OF MILK FROM INDIVIDUAL HOLSTEIN COWS

Abstract

ABSTRACT In the present study, the relationship between somatic cell counts (SCC) and composition (total solids, fat, protein and lactose content) of milk from individual Holstein cows was investigated in two different farms. Farm A had 43 lactating cows and produced bulk milk with mean SCC below 500,000 cells/mL. Farm B had 38 lactating cows that produced bulk milk with SCC usually above 1,000,000 cells/mL. Milk samples were collected three times from all lactating cows in both farms, with 60-day intervals between collections. Milks from farm A presented mean SCC levels that ranged from 143,000 to 549,000 cells/mL, while counts in farm B ranged from 1,187,000 to 3,432,000 cells/mL. SCC produced positive correlations (p < 0.05) only with protein content in farm A. A significant negative relationship (p < 0.05) was observed between log SCC and total solids and lactose in farm B. The results indicate that SCC of individual cow’s milk significantly correlate with a decrease in milk constituents only under conditions of average SCC in bulked milk above 1,000,000 cells/mL.