Univ. of Nebraska researchers conducted a trial to evaluate the effects of vaccination on the probability of feedlot steers to shed E. coli 0157:H7 in the feces, and for the organism to colonize in the terminal rectum. A total of 288 steers were allotted to one of two treatments, either vaccination or no vaccination. Fecal samples were collected from the rectum of each steers on days 1, 14, 28, and 56. At slaughter time (day 57), mucosal samples were collected from each steer by scraping the mucosal lining of the rectum. The probability to shed E coli 0157:H7 in the feces did not differ significantly between vaccinated and non-vaccinated steers. However, the probability to be colonized by E. coli 0157:H7 in the terminal rectum was dramatically reduced by vaccination (0.7% vs. 27.0% for vaccinated and non-vaccinated, respectively). These results suggest that vaccination may be a promising pre-harvest intervention for the control of E. coli 0157:H7 in feedlot cattle (Peterson et. al. J. Anim. Sci. [Suppl. 1]: Abstract 379).