| Abstrakt: |
As part of a larger study to assess risk factors associated with hide and carcass contamination of beef cattle during transport to slaughter, a total of 281 salmonellae were isolated from 1,050 rectal, hide, carcass, and environmental samples. For feedlot cattle, salmonellae were recovered from 4.0% of rectal samples, 37.5% of hide samples, 19.0% of carcass samples, and 47.4% of environmental samples. For nonfeedlot cattle, salmonellae were recovered from 10.9% of rectal samples, 37.5% of hide samples, 54.2% of carcass samples, and 50.0% of environmental samples. Overall, the five serotypes most commonly associated with feedlot cattle and their environment were SalmonellaAnatum (18.3% of the isolates), SalmonellaKentucky (17.5%), SalmonellaMontevideo (9.2%), SalmonellaSenftenberg (8.3%), and SalmonellaMbandaka (7.5%). The five serotypes most commonly associated with nonfeedlot cattle and their environment were SalmonellaKentucky (35.4%), SalmonellaMontevideo (21.7%), SalmonellaCerro (7.5%), SalmonellaAnatum (6.8%), and SalmonellaMbandaka (5.0%). Antimicrobial susceptibility testing of all of the isolates associated with feedlot cattle revealed that 21.7% were resistant to tetracycline, compared with 11.2% of the isolates associated with nonfeedlot cattle. None of the other isolates from feedlot cattle were resistant to any of other antimicrobial agents tested, whereas 6.2% of nonfeedlot cattle isolates were resistant to more than four of the antimicrobial agents tested. |
