Comparison of chlorhexidine and alcohol‐based antisepsis on the paralumbar fossa in cattle

Objective To determine skin reaction, post‐treatment reduction (immediate effect), and 1 hour post‐treatment reduction (sustained effect) of aerobic bacterial colony forming units (CFU) following three antiseptic protocols in cattle. Study design Prospective, randomized experimental study. Animals Eighteen cows. Methods Three sites in each paralumbar fossa were clipped and randomly assigned to one of three treatment groups: 5 minute 4% chlorhexidine gluconate scrub (CHG); 90 second 80% ethanol scrub (ET); 90 second 70% isopropyl alcohol scrub (IPA). All sites were monitored at all sampling time points and at 24 hours following treatment for adverse skin reaction. Samples were collected pre‐, immediately post‐, and 1 hour post‐treatment and plated in duplicate. Bacterial counts were shifted to eliminate zeroes, log10 transformed, and averaged. ANOVA was used to compare differences in mean reduction in log10CFU/ml between groups. Results Reduction in log10CFU/ml was more pronounced immediately after application of IPA (p = .001) and ET (p = .001) than CHG. This reduction was better sustained after preparation with CHG than ET (p = .005) but not IPA. Immediate and sustained reductions in bacterial loads did not differ after application of IPA or ET. No adverse skin reactions were noted. Conclusions Skin preparation with alcohol‐based antiseptics was well tolerated and improved immediate bacterial reduction compared to CHG. This reduction was better sustained 1 hour after application of CHG than ET, but no difference was detected between CHG and IPA. Clinical relevance Lack of adverse skin reaction and performance provide evidence to support skin preparation with alcohol‐based antiseptics in cattle.