The change in the proportion of cattle fecal pats positive for <i>E</i>. <i>coli</i> O157:H7 over time.

<p>(A) The proportion of fecal pats positive for <i>E</i>. <i>coli</i> O157:H7 by control and intervention groups, pre- and post-intervention. Bars indicate 95% confidence interval after adjusting the standard errors for clustering within pens. (Number of fecal samples = 2719) (B) Box-plots of the (unadjusted) change in within-pen prevalence of positive fecal pats within each pen (post- minus pre-intervention prevalence). (Number of fecal samples = 2719).</p

Results of mixed effect logistic regression models to assess the association between weather variables and the log odds of <i>E</i>. <i>coli</i> O157:H7 presence in fecal pats, after adjusting for pen and date as random effects.

<p>Results of mixed effect logistic regression models to assess the association between weather variables and the log odds of <i>E</i>. <i>coli</i> O157:H7 presence in fecal pats, after adjusting for pen and date as random effects.</p

Mean temperature, dew-point, relative humidity and mean precipitation during the seven days preceding each sampling date.

<p>Points show 7-day mean of average daily values. Upper and lower horizontal lines show 7-day means of maximum and minimum daily values. Bars represent mean precipitation over the 7 days preceding the sampling date.</p

Proportion of fecal pats positive for <i>E</i>. <i>coli</i> O157:H7 by pen, and pen-level variables.

<p>Data shown from pre-intervention time-point only (number of fecal samples = 1400). Light gray indicates year 1 (2014). Dark gray indicates year 2 (2015). Bars indicate 95% confidence intervals. Note: clustering of pens by sampling date is not shown.</p

The prevalence of <i>Escherichia coli</i> O157:H7 fecal shedding in feedlot pens is affected by the water-to-cattle ratio: A randomized controlled trial

<div><p><i>Escherichia coli</i> O157:H7 fecal shedding in feedlot cattle is common and is a public health concern due to the risk of foodborne transmission that can result in severe, or even fatal, disease in people. Despite a large body of research, few practical and cost-effective farm-level interventions have been identified. In this study, a randomized controlled trial was conducted to assess the effect of reducing the level of water in automatically refilling water-troughs on fecal shedding of <i>E</i>. <i>coli</i> O157:H7 in feedlot cattle. Pens in a feedlot in the Texas Panhandle were randomly allocated as control (total number: 17) or intervention (total number: 18) pens. Fecal samples (2,759 in total) were collected both at baseline and three weeks after the intervention, and tested for the presence of <i>E</i>. <i>coli</i> O157:H7 using immunomagnetic bead separation and selective culture. There was a strong statistical association between sampling date and the likelihood of a fecal sample testing positive for <i>E</i>. <i>coli</i> O157:H7. Pen was also a strong predictor of fecal prevalence. Despite accounting for this high level of clustering, a statistically significant association between reduced water levels in the trough and increased prevalence of <i>E</i>. <i>coli</i> O157:H7 in the feces was observed (Odds Ratio = 1.6; 95% Confidence Interval: 1.2–2.0; Likelihood Ratio Test: p = 0.02). This is the first time that such an association has been reported, and suggests that increasing water-trough levels may be effective in reducing shedding of <i>E</i>. <i>coli</i> O157:H7 in cattle feces, although further work would be needed to test this hypothesis. Controlling <i>E</i>. <i>coli</i> O157:H7 fecal shedding at the pre-harvest level may lead to a reduced burden of human foodborne illness attributed to this pathogen in beef.</p></div

Proportion of fecal pats positive for <i>E</i>. <i>coli</i> O157:H7 by sampling date and weather conditions.

<p>Data shown from control pens only (number of fecal samples = 1360). Light gray indicates year 1 (2014). Dark gray indicates year 2 (2015). Bars indicate 95% confidence intervals.</p