Platt, Tammy M.; Loneragan, Guy H.; Scott, H. Morgan; Norby, Bo; Thomson, Daniel U.; Brown, Michel S.; Ives, Samuel E.; Brashears, Mindy M. (United States of America)
American Journal of Veterinary Research (2008)
Twenty single source crossbred steers were enrolled in a cohort study. Steers were randomly assigned to an exposed cohort (n=10) or an unexposed cohort (control cohort:10). Chlortetracycline (22 mg/kg) in cottonseed meal was administered to the exposed cohort on days 0 through 4, 6 through 10, and 12 through 16/ The control cohort was administered only cottonseed meal.
Fecal samples were collected from 16 steers on days -7, 0, 2, 6, 8, 12, 14, 22, 26 and 22, and Escherichia coli and Enterococcs spp were isolated.
AST Method: Broth Microdilution
Reference explicitly reports AST breakpoints: False
Reference reports using a MIC table: Uncertain
Is Excluded: False
| Country | Sub-Region | Sub-Region Detail |
|---|---|---|
| United States of America | Texas (State) | None |
| ID | Note | Resolution |
|---|
| Title | Host | Host | Production Stage | Description | ROs |
|---|---|---|---|---|---|
| Chlortetracycline use | Cattle | Beef Steers | Feedlot | Cattle fed cottonseed meal with or without chlortetracycline (22 mg/kg) added. (Data from days 14-19) | 1 |
| Chlortetracycline use | Cattle | Beef Steers | Feedlot | Cattle fed cottonseed meal with or without chlortetracycline (22 mg/kg) added. (Data from days 8-12) | 1 |
| Chlortetracycline Use | Cattle | Finishers | Farm | Steers administered chlortetracycline (22 mg/kg) in feed in 3 separate 5-day periods (1 day of no AMU between each period). Factor =avg of all sampling timepoints (days -7, 0, 2, 6, 8, 12, 14, 19, 22, 26, 33). Both groups had other AMU in feed. | 3 |