Limited effects of a commercial direct-fed microbial on weaning pig performance and gastrointestinal microbiology

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 other groups. Total VFA concentration in the DFM group was signifi cantly higher than that in the antibiotic-fed group. Prevalence of Salmonella serovars and rotavirus following challenge was similar in all groups.