The term mastitis describes an inflammation of the mammary tissues. The term is usually used to refer to the clinical signs associated with an infection of the udder, although an infection may occur without any outward signs being seen (a so-called sub-clinical infection). The agents responsible for causing mastitis can be divided into two groups by their method of infection; environmental agents, which are present in the cows environment and move onto each animal individually; and contagious agents, which move from cow to cow through direct or indirect contact. More recently pathogens responsible for causing mastitis have been graded on a continous scale; some are more "contagious" and others are classed as more "environental" (see figure below):
The Five Point Plan to reduce contagious mastitis.
Strategies to control environmental mastitis.
Use the California Mastitis Test protocol to identify subclinically infected quarters. You can grade cases of mastitis to help decide on most appropriate therapy.