Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 6/3/2008
Publication Date: 8/4/2008
Citation: Brown Brandl, T.M., Berry, E.D., Wells, J., Arthur, T.M., Nienaber, J.A. 2008. The impact of stress level on fecal bacteria and pathogen shedding in feedlot cattle. American Society of Agricultural and Biological Engineers. Paper No. 084178. St. Joseph, MI:ASABE.
Interpretive Summary: Cattle frequently carry E. coli O157:H7, a pathogen that may cause human illness. Chances of human contact with the pathogen increase as the number of organisms increase; therefore, we are highly interested in learning how to reduce that number. The number of pathogenic organisms increases during the summer and one thought is that this may be related to stress. Therefore, these studies were designed to study the possible connection between stress and the number of pathogenic organisms. Two types of stress were studied. The first summer, stress caused by high environmental temperatures was measured. The second summer, stress caused by moving and capturing animals was measured. In both summers, the numbers of neither pathogenic nor non-pathogenic organisms were affected by the stresses we measured. We concluded that there were no strong correlations of stress to increases in E. coli O157:H7 organism shedding by cattle.
Technical Abstract: The prevalence of E. coli O157:H7 in feedlot cattle increases during the warmer months of the year and during transportation. This study was conducted to determine whether stress contributes to this increase. Feedlot heifers of four breeds (hide colors: red, black, tan, and white) were selected on the basis of weight, and assigned to pens on the basis of hide color, weight, and fecal prevalence of E. coli O157. On days 0, 28, 56, and 84 animals were weighed, condition scored, and temperament scored. At the same time, fecal grab samples were collected for each animal individually. The presence and levels of E. coli O157 and levels of generic E. coli in feces were determined. Over the entire study period, there were no clear trends between the heat stress or handling stress and fecal generic E. coli levels or E. coli O157 prevalence in feces.