Relationship between somatic cell counts and milk production and composition in Jersey cows

The main components in milk from cows that are affected by mastitis can be in different amounts according to the racial characteristics. Thus, the association between the somatic cell counts (SCC) and these components may also differ in milk from Jersey cows. This study evaluated the effect of the SCC in milk from Jersey cows on milk production and its physicochemical composition. For 71 months, data from 3244 milking and 300 cows were evaluated considering the effect of the SCC on milk production (kg cow day -1 ), percentage of fat, protein, lactose, total solids, and nonfat solids. The probable factors associated with fluctuation in milk production based on somatic cell score, lactation number and rainfall were also evaluated by regression models. Milk composition was changed according to the SCC. In general, the higher the SCC in milk, the lower the contents of lactose, fat, and solids, with exception of the protein content, which increased. Losses in milk production of Jersey cows were observed for milk with counts above 50,000 somatic cells per ml.