Results: In the fi eld study, average daily gain of antibiotic-fed pigs was larger than that of DFM-fed pigs. Other growthperformance parameters, fecal Escherichia coli concentrations, and prevalence of Salmonella serovars were similar among treatment groups. Under experimental conditions, total fecal coliform concentration was signifi cantly lower in the antibiotic-fed group than in the two ot...