The rates of new infections are the highest during the first two weeks of the dry period and the last two weeks of the dry period. New infection rates are also high in early lactation and diminish as the lactation proceeds. Infection Dynamics To understand mastitis infection, you must realize how its level changes on a herd basis. Somatic Cells Described Somatic means of the body. Thus, a somatic cell is simply a body cell.
Examples are skin cells, muscle cells, bone cells, or virtually any cell in the body.
In milk, however, the predominant cell types are epithelial and white blood cells. Epithelial cells of the alveoli are most numerous and active during early lactation when milk production is greatest. Throughout the cow's lactation these cells slowly age and gradually are sloughed into the milk. Milk production drops during late lactation as these cells become fewer and less productive. While this is a dynamic process, the number of epithelial cells found in milk is relatively constant throughout lactation.