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Mastitis Tip of the Month -- Environmental Mastitis

Dairy Pipeline: November 1999

Gerald M. (Jerry) Jones
Extension Dairy Scientist, Milk Quality and Milking Management
Virginia Tech
(5400 231-4764

Well managed dairy herds with low somatic cell counts (SCC below 200-300,000) often may experience problems with onsets of clinical mastitis. Approximately 40-45% of the mastitis cases in low SCC herds are caused by environmental pathogens which can be difficult to detect because of their short duration. Cows in low SCC herds are most susceptible to environmental streptococci and coliform (E. coli, Klebsiella) infections after drying off and just prior to calving but which appear in early lactation.

The main factor in controlling infection from the environment is to keep cows clean and dry between milkings, minimizing opportunity for teats to become exposed to environmental pathogens. Dirty teats and udders are difficult to properly clean and dry without upsetting the milking routine.

These infections are usually associated with wet and dirty conditions that expose teat ends to bacterial contamination. Dirty housing and calving environments, certain types of bedding materials, improper or inadequate cow preparation for milking and milk letdown, and conditions within milking systems that create liner slips during milking are all factors that can potentially lead to mastitis. Infections by environmental pathogens can be reduced by dry cow therapy, pre- and post-milking teat dipping, clean teats and udders where hair has been removed, proper preparation for milking, milking system maintenance, fly control, and controlling mastitis in heifers at calving.

Pathogen identification and treatment records are important. Dietary supplementation with vitamin E and selenium during the late dry period can affect immunity levels of cows and heifers. For more information on environmental streptococcal and coliform mastitis, see Extension Publication 404-234.

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