Evaluation of Chlorhexidine as a Premilking Teat Disinfectant for the Prevention of Intramammary Infections During Lactation

Abstract

A study was conducted for 15 months to evaluate efficacy of a 0.35% chlorhexidine teat dip as a premilking teat disinfectant based on reduction of naturally occurring new intramammary infections. Predipping was compared with a negative control using a split-udder experimental design. All teats were dipped after milking with the same 0.35% chlorhexidine teat dip. Most new major pathogen intramammary infections were caused by Streptococcus species, primarily Streptococcus uberis and Streptococcus equinus and gram-negative bacteria, primarily Escherichia coli. Percentage of quarters newly infected by major mastitis pathogens was 30.6% lower in mammary glands with teats predipped and postdipped in chlorhexidine than in mammary glands with teats postdipped only, and differences between treatment groups approached significance. New infections by coagulase-negative Staphylococcus species were significantly lower in mammary glands with teats predipped and postdipped than in mammary glands with teats postdipped only. When all mastitis pathogens were combined, percentage of quarters newly infected by major and minor mastitis pathogens was significantly lower in the predipped and postdipped group than in the postdipped only group. No statistical differences in incidence of clinical mastitis between treatment groups were observed. No chapping or irritation of teats was observed and no adverse effects were detected using chlorhexidine as a premilking and postmilking teat disinfectant. Results of this study suggest that premilking teat disinfection with chlorhexidine in association with good udder preparation and postmilking teat disinfection can further reduce the occurrence of new intramammary infections during lactation.