(Edtor's note: This article was written by the NMC (formerly the National Mastitis Council) and originally appeared on eXtension.org.)
How does postmilking teat disinfection work?
The rate of new udder infection is related to the number of mastitis-causing pathogens on teat ends. Disinfecting teats with a germicidal agent immediately after milking kills most of the pathogens on teats. This in turn reduces the chance of those pathogens getting into the udder.
Postmilking teat disinfection is especially effective against the contagious pathogens Staphylococcus aureus and Streptococcus agalactiae. While milking can spread any type of mastitis pathogen, these two pathogens in particular spread from cow to cow during the milking process. Postmilking teat disinfection is less effective in reducing the new infection rate of “environmental” pathogens such as coliforms and Streptococcus species other than Streptococcus agalactiae. Control of environmental pathogens requires management practices including maintaining cows in a clean, dry environment; good premilking hygiene, including premilking teat disinfection and thoroughly drying teats; and using functionally adequate milking machines. Milkers should continue postmilking teat disinfecting as a routine part of milking procedures, even if Streptococcus agalactiae has been eliminated and somatic cell counts are low.
What to expect
More than 50% of new udder infections can be prevented by disinfecting teats with an effective product immediately after every milking. Teat disinfection does not affect existing infections. Existing infections are best eliminated by dry cow treatment and culling chronically infected cows. Prevention of new infections by teat disinfection and elimination of existing mastitis cases reduces the level of mastitis in a dairy herd year by year. Improvements, such as decreased cases of clinical mastitis and/or lowered herd somatic cell counts, generally can be observed within a few months. Do not expect miracles overnight!
How to apply
Postmilking teat disinfectants can be applied either by dipping or spraying. Either method is acceptable, if done in a manner that thoroughly covers the entire teat. Care should be taken to ensure that all four teats are covered. The disinfectant should be applied immediately after every milking.
Store teat disinfectants in cool, dry areas. Do not allow disinfectants to freeze! Keep containers closed to prevent contamination, and do not use after the expiration date. Do not assume that teat disinfectants will kill all pathogens. Some pathogens can survive in disinfectant under some conditions.