Location: Meat Safety and QualityTitle: Evaluation of commercial ß-agonists, dietary protein, and shade on fecal shedding of Escherichia coli O157:H7 from feedlot cattle
|Wells, James - Jim|
|KIM, M - National Institute Of Animal Science|
Submitted to: Foodborne Pathogens and Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/16/2017
Publication Date: 11/9/2017
Citation: Wells, J.E., Berry, E.D., Kim, M., Shackelford, S.D., Hales, K.E. 2017. Evaluation of commercial ß-agonists, dietary protein, and shade on fecal shedding of Escherichia coli O157:H7 from feedlot cattle. Foodborne Pathogens and Disease. 14(11):649-655. https://doi.org/10.1089/fpd.2017.2313.
Interpretive Summary: Escherichia coli O157:H7 is a foodborne pathogen commonly associated with cattle feces. ß–agonists are compounds fed to feedlot cattle to improve performance, and previous research indicated that these compounds might impact fecal shedding of this pathogen. However, these studies were small in scale, and results were conflicting relative to potential impact on pathogen shedding. A series of large studies were conducted with feedlot cattle to determine if feeding ß–agonists prior to harvest affected fecal shedding and concentrations of E. coli O157:H7. ß–agonists had no significant impact in feedlot cattle on fecal prevalence or the percentage of animals shedding E. coli O157:H7 at high levels. Furthermore, the addition of soybean meal to the feedlot diet appeared to reduce the percentage of animals shedding E. coli O157:H7 at high levels. This novel finding needs to be studied in greater detail.
Technical Abstract: Escherichia coli O157:H7 is a foodborne pathogen commonly associated with cattle feces. Diet, including dietary supplements such as b-agonists, may impact fecal shedding of this pathogen. A series of three experiments were conducted to determine if the b- agonists ractopamine hydrochloride (RAC) or zilpaterol hydrochloride (ZH) would impact the level or prevalence of fecal E. coli O157:H7 shedding. In Experiment 1, dietary RAC did not impact fecal shedding of E. coli O157:H7 based on the level or prevalence, but the addition of dietary soybean meal (SBM) in the study did reduce E. coli O157:H7 shedding. In Experiments 2 and 3,dietary ZH did not affect fecal E. coli O157:H7 shedding as determined by enumeration or prevalence, but in Experiment 2 the addition of 30% (dry matter basis) wet distillers grains with solubles (WDGS) in the diet tended to increase E. coli O157:H7 shedding. Shade is a potential management tool to reduce heat stress in cattle, and in Experiment 3 the presence of shade over the feedlot pens did not affect E. coli O157:H7 shedding. The use of b-agonists in cattle diets did not significantly affect fecal shedding of E. coli O157:H7, and in particular the percentage of animals shedding enumerable levels of the pathogen did not change, indicating that there was not a change in colonization. As has been reported previously and indicated again in this study, the use of WDGS in the diet may increase E. coli O157:H7 shedding. In contrast, the addition of SBM to cattle diets, to increase the dietary crude protein, appeared to reduce E. coli O157:H7 shedding,but this potential dietary intervention needs to be confirmed with additional research.