The influence of iodine teat dipping and an external teat sealant in heifers on bacterial isolation from quarter milk culture obtained post-calving

Antibacterial Activities of Acetic Acid against Major and Minor Pathogens Isolated from Mastitis in Dairy Cows

The present study evaluated the antimicrobial activities of acetic acid against bovine mastitis pathogens compared to lactic acid and lauric and caprylic saturated fatty acids. Eleven mastitis pathogens were isolated from sub-clinical and clinical bovine mastitis cases for the study. An initial screening of their antibacterial activities by agar well diffusion method was performed. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each acid were obtained using a microdilution method; each acid was diluted from stock solution and then were diluted with culture broth to reach concentrations ranging from 4 to 0.004% w/v. The results showed acetic acid had the highest zone of inhibition against all pathogens except Escherichia coli compared with lauric and caprylic acids. The MIC and MBC were lowest for acetic acid against both Gram-positive (except Staphylococcus chromogenes from the coagulase negative staphylococci (CNS) group) and Gram-negative pathogens, intermediate for lactic and caprylic acids and greatest for lauric acid. In conclusion, acetic acid had antimicrobial activities against most mastitis pathogens compared with other acids. Further studies are needed to optimize the formulation and concentration of acetic acid for teat-dipping agent in the future.

Adhesion Capacity of Weissella cibaria to Bovine Mammary Tissue and the Effect of Bio-Sealant Topical Application on Physicochemical Properties of Milk

The ability of a probiotic strain (Weissella cibaria) to adhere on tissue and the effect of its topical application in nipples of lactating cows on physicochemical characteristics of milk were evaluated. An ex vivo model was used to demonstrate the adhesion capacity of W. cibaria. Tissue samples were randomly distributed in three different solutions corresponding to three treatments (a nipple bio-sealant formulation, sterile PBS solution and biomass of W. cibaria, sterile PBS solution without microorganism addition). The number of bacteria adhered in tissue was quantified and observed using electron microscopy. Additionally, a bio-sealant prepared with W. cibaria was topically applied to nipples of dairy cows. Milk samples were taken every 7 days for 60 days. Two controls were used. California mastitis test (CMT), somatic cell count, electrical conductivity, pH, density, and acidity were evaluated. The adhesion capacity of W. cibaria strain to epithelial cells of bovine teat tissue samples was demonstrated. When the strain was added as a bio-sealant, the adhesion capacity of W. cibaria was 80.44%. The response variables did not show significant differences among treatments; these results indicate the safety of the topical application of W. cibaria on the bovine mammary gland. In this study, a new safe way of administering probiotic microorganisms in nipples of lactating cows was demonstrated. W. cibaria adheres to the bovine mammary tissue and can be topically applied in nipples of lactating cows without affecting the physicochemical characteristics of milk.