Solutions of Zinc oxide and silver nitrate as an alternative to bovine udder antisepsis

ABSTRACT:

This study aimed to analyze the zinc oxide and silver nitrate solutions as an alternative antiseptic for cow teats (in situ), considering the lack in the literature about these compounds uses in mastitis prophylaxis. First microdilution tests med and MBC (Minimal Bactericidal Concentration were perfor in order to determine the antimicrobial activity of zinc oxide and silver nitrate solutions over 30 Staphylococcus spp. isolates, obtained from cows with mastitis. All strains tested showed sensitivity to both solutions, but the silver nitrate solution had lower MBC values (3,05 to 97,65ug/ml) compared with zinc oxide solution MBCs (97,65 to 6,250 ug/ml). Subsequently, the antiseptic teat tests were conducted (in situ) by immersing the teats in same antimicrobial solutions tested in the first experiment. Therefore, 40 teats were used (n = 40) originating from slaughtered cows were divided into 4 groups of 10 teats, to test test zinc oxide 3% (30mg/mL) and silver nitrate 1% (10mg/mL) solutions and their respective controls. The teats were submitted to mesophilic count on the teat surface (CFU/cm²) before and after immersion in tested solutions. As a result, all the solutions (zinc oxide and silver nitrate) had a significant reduction in CFU/cm² until 60 minutes after immersion (M 0’ to 60 M’). Silver nitrate solution showed a reduction of CFU/cm² significantly higher compared to the group treated with zinc oxide solution. These results validate the potential use of zinc oxide and silver nitrate solutions in dairy cows as a pre- and post-dipping antiseptic.

INDEX TERMS: Teats antisepsis; zinc oxide; silver nitrate; cattle