Table 2.
Herd-level effect of calf-housing system on the proportion of antimicrobial-resistant Escherichia coli
| Antimicrobial agent | PR1
|
P-value | |
|---|---|---|---|
| IP (n = 6) | GP (n = 6) | ||
| Ampicillin | 80.0 | 72.6 | 0.43 |
| Cefoxitin | 48.9 | 59.1 | 0.73 |
| Ceftiofur | 29.6 | 25.1 | 0.85 |
| Ceftriaxone | 8.0 | 4.0 | 0.43 |
| Chloramphenicol | 42.6 | 45.7 | 0.75 |
| Ciprofloxacin | 1.8 | 9.0 | 0.16 |
| Gentamicin | 21.2 | 5.8 | 0.73 |
| Nalidixic acid | 2.5 | 10.3 | 0.12 |
| Neomycin | 53.3 | 46.9 | 0.69 |
| Streptomycin | 83.1 | 72.9 | 0.18 |
| Tetracycline | 87.2 | 79.1 | 0.24 |
| TMS2 | 45.4 | 54.3 | 0.49 |
1
PR = proportion of calves with resistant E. coli isolates by calf-housing system (IP or GP); IP = calves housed in individual pens without direct contact with neighboring calves and fed milk or milk replacer 2 to 3 times a day; GP = calves housed in group pens with 3 to 25 calves being fed free-choice acidified milk.
2
Trimethoprim sulfamethoxazole.