Survey of Salmonella serotypes in feedlot cattle.

A national study of health and management of cattle in feedlots was conducted. Within this study, the prevalence of Salmonella spp. in fecal samples was determined. Fifty fecal samples were collected from each of 100 feedlots. Within each feedlot, 25 fresh fecal samples were collected from the floor of the pens of cattle which had been on feed the shortest and 25 from those on feed the longest periods of time. The total number of samples collected was 4,977; 2,484 and 2,495 from pens of cattle on feed the shortest and longest times, respectively. Salmonella spp. were recovered from 38% (38 of 100) of the feedlots. Salmonella spp. were recovered from 5.5% (273 of 4,977) of all samples and from 3.5% (88 of 2,484) and 7.4% (185 of 2,495) of samples from pens of cattle shortest and longest on feed, respectively. The most common serotype recovered was S. anatum (27.9%), followed by S. montevideo (12.9%), S. muenster (11.8%), S. kentucky (8.2%), and S. newington (4.3%). The most common serogroups identified were E1 (39.6%), C1 (20.7%), and B (10.4%). Shedding of the serotypes most commonly associated with human illness occurred infrequently (13 of 273: 4.8%). This study provides information on the status of Salmonella spp. from cattle in feedlots and may serve as baseline information for future studies.