Reduction of E. coli   O157:H7 in Beef Feedlot Cattle using Varying Doses of a Direct-Fed Microbial

This research evaluated three different doses of Lactobacillus acidophilus strain NP 51 and a combination treatment of NP51 and NP45 on the prevalence of Escherichia coli O157 in finishing beef cattle. The highest concentration of NP51 was the most effective in reducing fecal shedding. There were no detrimental effects of the treatments used in these studies on animal performance.

Funded in part by The Beef Checkoff

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Objectives

The objective was to evaluate the effects of three different doses of Lactobacillus acidophilus strain NP 51 and a combination treatment of NP51 and NP45 on prevalence of Escherichia coli O157 in finishing beef cattle.

Conclusions

Cattle receiving a high level dose of NP51 were, overall, 77% less likely to shed E. coli O157 in their feces relative to those receiving the control diet. While supplementing cattle with lower doses of NP51 resulted in decreased fecal prevalence of the organism, using the high-level dose of NP51 was most effective. A lower percentage of cattle were carrying detectable E. coli O157 on their hide among those receiving DFM compared to the control groups. Supplementing cattle with Lactobacillus acidophilus strain NP51 based DFM continues to show promise as a pre- harvest food safety intervention strategy to control E. coli O157 in finishing beef cattle. The effectiveness of using the high- level dose of NP51 may make it most advantageous in improving food safety pre-harvest.

Deliverable

This study confirmed that cattle feed supplemented with a direct fed microbial reduces fecal shedding of E. coli O157:H7, while having either little or no negative impact on performance.