ABSTRACT
MASTITIS DEFINITION/OVERVIEW Mastitis is one of the major diseases of dairy cattle worldwide and it has a significant economic cost. For example, it has been estimated to cost the US dairy industry over $1 billion annually. Although the incidence of clinical mastitis in a dairy herd can vary widely depending on location and risk factors, subclinical mastitis also has a major economic cost. Cows with subclinical mastitis will not have detectable changes in the milk, but they will have reduced milk yields and milk quality. The price that farmers are paid for their milk is based on a number of factors, including hygienic quality, as assessed by somatic cell count (SCC) and/or bacterial content. High levels of mastitis will lead to high SCCs and bacterial levels, leading to substantial deductions from the milk price paid to the farmer. In some countries farmers may be unable to sell their milk for human consumption.
