Efficacy of a germicidal post milking barrier-type teat dip in preventing intramammary infections.

Five commercial dairy herds with 269 lactating cows participated for 12 months in a field trial to determine the effectiveness of a barrier teat dip containing chlorous acid/chlorine dioxide germicide. The right quarters of the cows in two herds and the left quarters of the cows in three herds were dipped in the experimental teat dip after the removal of the milking machine. The other quarters were dipped in a conventional 0.5 per cent iodophor product. Compared with this control product, teat dipping with the experimental dip reduced the number of new intramammary infections by 18.8 per cent, infections with major pathogens by 13.6 per cent, infections with minor pathogens by 16.8 per cent and clinical mastitis by 33.3 per cent. Statistical analysis indicated a trend towards decreased intramammary infections with coliforms and coagulase-negative staphylococci when the experimental teat dip was used. It was concluded that under the conditions of this investigation it was effective in preventing new infections due to both contagious and some environmental pathogens. However, the data suggested that it could adversely affect the condition of the skin of the teat when it was used after incorrect preparation of the udder.