|Koohmaraie, Mohammad - FORMER ARS EMPLOYEE|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 6, 2009
Publication Date: August 5, 2009
Citation: Wells, J., Shackelford, S.D., Berry, E.D., Kalchayanand, N., Guerini, M.N., Varel, V.H., Arthur, T.M., Bosilevac, J.M., Freetly, H.C., Wheeler, T.L., Ferrell, C.L., Koohmaraie, M. 2009. Prevalence and Level of Escherichia coli O157:H7 in Feces and on Hides of Feedlot Steers Fed Diets With or Without Wet Distillers Grains with Solubles. Journal of Food Protection. 72(8):1624-1633. Interpretive Summary: The feeding of distillers grains to cattle has increased in recent years as a consequence of its increased availability and the increased price of corn. In this study with 600 steers in the feedlot environment, the level and prevalence for E. coli O157:H7 on hides and in feces was monitored for 245-days through the growing and finishing phases of production. In the finishing phase, animals that received 40% WDGS (on dry matter basis) in their diet had greater prevalence of the pathogen on hides and in feces compared to control animals fed corn-grain only. Although the magnitude of the differences in E. coli O157:H7 observed between the two finishing phase diets may have been inflated by the unexpectedly low prevalence in the pens of animals fed corn and the large variation in the pathogen across the pens of animals fed 40% WDGS. More E. coli O157:H7 associated with cattle at the feedlot could result in a greater pathogen load associated with animals at the time of harvest. Additional studies with feedlot animals in the summer months are needed to determine if high levels of WDGS in the finishing diet affect pathogen load in the summer when E. coli O157:H7 prevalence is highest.
Technical Abstract: The objective of this study was to determine if wet distillers grains with solubles (WDGS) in diets affected Escherichia coli O157:H7 in growing and finishing cattle, so steers (n = 603) were randomly assigned to diets with and without WDGS. Hide and fecal samples were collected monthly (October through June) from each animal for enumeration and enrichment of E.coli O157:H7. In the growing phase (0 or 13.9% WDGS diets), fecal prevalence for E. coli O157:H7 in steers fed a diet with WDGS was twice that of control steers (P < 0.001). In the finishing phase (0 or 40% WDGS diets), average prevalence in feces (P < 0.001) and on hides (P < 0.001) was higher for cattle fed WDGS. The average percentage of fecal E. coli O157:H7 enumerable samples during the finishing phase for cattle fed WDGS was 2.7% compared to 0.1% for corn (P < 0.001). The average percentage of E. coli O157:H7 enumerable hide samples was not different between diets, but the cattle fed WDGS had higher levels (P < 0.05). Animals fed WDGS had higher levels of generic E. coli (P < 0.001), higher pH (P < 0.001), and lower concentrations of L-lactate (P < 0.001) in feces. These results indicate that feeding 40% WDGS may increase the level and prevalence of E. coli O157:H7 in and on feedlot cattle, although the magnitude of the difference in this study may have been increased because of low prevalence in the control pens.