Efficacy of the SRP ® Vaccine and/or low dose Bovamine® Against Fecal Shedding of E. coli O157:H7 in a Randomized Trial of Commercial Feedlot Cattle
Vaccine/microbial combinations that combine limited bacterial iron up-take and probiotic effects can reduce E.Coli shedding in a feedlot environment, according to David G.Renter, Kansas State University.E. coli O157:H7 inhabits the hindgut of cattle and is commonly shed in the feces. However, a high variability exists across cattle with some animals shedding large amounts of the bacteria and others very little.
Less than 5 per cent of animals shed at what scientists call 'high levels' (>104 cfu/g) although the feeding of distiller's grains can increase fecal shedding of E. coli O157:H7 in cattle.
This study looked at the use of protein-based vaccines containing siderophore receptors and porin (SRP®) and/or a direct-fed microbial (DFM) against fecal shedding of E. coli O157:H7.
Pens of commercial feedlot cattle fed a corn-based diet with around 25 per cent DG (dry matter basis) were tested during the summer. The O157:H7 SRP® vaccine inhibits iron uptake by the bacteria while Bovamine® direct-fed microbial has probiotic effects. Both are commercially available in the United States.
The study design included two pen-level measures of fecal shedding: overall fecal prevalence of O157:H7 and the prevalence of high-shedding animals. Of all treatment protocols, only the two?dose SRP® significantly reduced overall fecal prevalence and the percentage of high shedders, with no significant interactions between treatment and time of sampling.
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The administration of the DFM had no significant effect on the prevalence of fecal O157:H7 or the prevalence of high shedders. With > 50 per cent reduction of E. coli O157:H7 shedding and > 75 per cent reduction in high shedders, this two-dose regimen of the E. coli SRP® vaccine appears to be an efficacious pre-harvest intervention in a commercial feedlot setting.
April 2013