EFFECT OF CLEANING AND SUBTHERAPEUTIC CHLORTETRACYCLINE ON SALMONELLA

Abstract The objective of this study was to evaluate the effect of stringent cleaning and subthera-peutic chlortetracycline (CTC) on Salmonella enterica (SE) prevalence in market age swine. Twenty-four finisher barns from one farm were enrolled in a 2X2 factorial study design. Treatments included 1) assignment to a “stringent ” or standard cleaning protocol and 2) inclusion of 50g of CTC/ton of feed or no feed antimicrobials. Barn swab samples were obtained pre- and post-cleaning for SE detection. Post-cleaning aerobic plate counts (APC) were collected. Feces were collected to determine SE prevalence pre-market. The stringent cleaning protocol resulted in decreased mean APC post-cleaning, but there was no difference in isolation of SE from the barn environment between cleaning protocols. Pigs housed in barns that received CTC had decreased odds of being SE positive, but there was no difference in the odds of a pig being SE positive between cleaning protocols. Introduction Contamination of the barn environment with Salmonella enterica (SE) has been sug-gested to be an important risk factor for SE infection in swine. All-in, all-out production practices with cleaning and disinfection between groups is often utilized to aid in the control of production impairing illnesses in swine. However, the effectiveness of these practices on the prevalence o