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The specific objectives of these experiments are to determine the prevalence of E. coli O157:H7 on the hides and in the feces of feedlot cattle in the same pens over time and to determine or estimate the number of cattle shedding E. coli O157:H7 that are necessary to contaminate the hides of over 50% of the animals in the pen.
Findings: The Meats Research Unit of the U.S. Meat Animal Research Center has collected data that clearly implicate cattle hides as the major source of E. coli O157:H7 on beef. Considering this fact, it is critical to determine the number of cattle harboring E. coli O157:H7 that it will take to contaminate the hides of most of the cattle in the same pen. This study has shown that large variations in rates of E. coli O157:H7 prevalence may exist between neighboring pens, including those that share water troughs. Also, large fluctuations in hide and fecal prevalence rates for E. coli O157:H7 can occur within a pen in a short span of time, as exemplified by the increase in hide prevalence from 3% to 94% in only a 2-week period. Additionally, from this data it would appear that the presence of animals shedding E. coli O157:H7 at high levels in their feces greatly affects the hide prevalence within a pen. One pen containing only two fecal-positive animals, one shedding at a high level, had a hide prevalence rate of 84%. Finally, transport to and holding in pens at the processing plant can lead to large increases in cattle hide prevalence for E. coli O157:H7.
<P> For complete projects details, view the <a href="http://www.beefresearch.org/CMDocs/BeefResearch/Prevalence%20of%20E.%20…; target="_blank">Project Summary. </a>