1. To develop a procedure for determining comparative levels of E. coli O157:H7 shed
by feedlot cattle.
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2. To determine if a relationship exists between the increase in serum cortisol levels
(stress response) resulting from common management practices and the shedding of
E. coli O157:H7.
Findings: Variables used for estimating animal temperament appear consistent throughout the trial groups of Excitable, Intermediate, and Calm cattle, however, cattle tended to change temperament groups throughout the feeding period. This implies that there were not great disposition differences, especially between the Calm and Intermediate cattle. It appears that Excitable cattle are not more likely to shed E. coli O157:H7. According to the prevalence data, it seems greater fecal shedding occurs in Calm cattle at later points in the feeding period. However, the greatest percentage of shedding occurred at the arrival sampling compared to the other sampling times. It would be interesting to further examine the potential for cross-contamination of E. coli O157:H7 during transport. Based on these data, it is difficult to determine whether or not a relationship exists between stress response and the fecal shedding of E. coli O157:H7 because of potential bias attributable to a relatively low occurrence of the pathogen. This research may serve as a helpful resource to others attempting to design a study investigating the relationship between stress and the shedding of E. coli O157:H7.