Apply teat dips immediately after milking machine removal. Sampling Schedule and Procedures Collect duplicate or two consecutive single quarter milk samples to determine existing infections in the herd at the beginning of the trial. Obtain a third sample when results of the first two samples do not agree. Culture single quarter milk samples monthly during the trial. A second quarter milk sample should be collected within seven daysfrom all quarters in which the bacteriological status of the gland had changed from the previous month.
Culture duplicate samples from cows calving and herd additions prior to inclusion in the trial.
When any quarter develops clinical mastitis, collect and culture duplicate milk samples from all four quarters before any treatment is administered. Collect and culture duplicate milk samples from individual cows at drying off or upon leaving the herd. In determining that a quarter is free of infection when it enters the trial, no pathogens may be recovered from two of the initial samples. The status of a quarter should be recorded as a bacteriologically-negative clinical case when bacteriological results of duplicate samples from a clinical quarter do not match. Clinical mastitis and IMI diagnosed during the first seven daysof lactation should not be included in data analyses of teat dip efficacy.