Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 17, 2011
Publication Date: April 1, 2011
Citation: Wells, J., Shackelford, S.D., Berry, E.D., Kalchayanand, N., Bosilevac, J.M., Wheeler, T.L. 2011. Reduction in dietary wet distillers grains alters Escherichia coli 0157:H7 in feces of cattle. In: Proceedings of the 2011 Congress on Gastrointestinal Function, April 18-20, 2011, Chicago, Illinois. Technical Abstract: Cattle fed finishing diets with distillers grains have been shown to more often have Escherichia coli O157:H7 in the feces and on the hides. The objectives of this study were to determine if pathogen levels and prevalence differ at higher level of wet distillers grains with solubles (WDGS) in the diet, if switching to a predominantly corn diet reduces pathogen load, and how long corn diets should be fed before reductions in pathogen load are observed. To accomplish these objectives, 608 heifers (20 pens, 27-33 animals per pen) were sorted into 1 of 5 treatments, and fed 0, 40, or 70% WDGS (DM basis). For 3 of the treatments, WDGS was reduced midway through the study. Treatment 0W0W (positive control) was corn grain fed continuously, and 40W40W (negative control) was 40% WDGS fed continuously. Treatments 40W0W, 40W15W and 70W15W were fed either 40% or 70% WDGS for the first 56 days, and switched to 0% or 15% WDGS, respectively, for the last 56 days. Samples of feces from each animal were collected 56 days before, day of, and up to 56 days after the dietary switch for the enumeration and detection of E. coli O157:H7. After the dietary switch, animals fed 0W0W diets had the lowest fecal prevalence and percent enumerable samples (10.2 and 3.23%), whereas animals fed 40W40W had the highest fecal prevalence and percent enumerable samples (70.1 and 29.2%; P < 0.05). Animals switched to lower levels of WDGS with the 40W0W, 40W15W, or the 70W15W, had lower fecal prevalence and percent enumerable samples (33.4 and 6.3%, 31.03 and 9.7%, 34.9 and 8.4%; P < 0.05) compared to the animals fed the 40W40W diet. Time after dietary switch was important, as animals fed lower levels did not have significantly lower fecal prevalence and percent enumerable samples until 56 days after the dietary switch. The study indicates that cattle can be switched to lower levels of dietary WDGS (15% or less) 56 days prior to slaughter to significantly reduce the E. coli O157:H7 load.