Table 5.
History of cattle colonized with tulathromycin-resistant M. haemolyticaa.
| Animal number | Days enrolled in study | M. haemolytica isolated ≥60 days on feed | Antimicrobial use | |||
|---|---|---|---|---|---|---|
| Antimicrobial (dose administered) | Administration route | Day of administration | Day of withdrawal | |||
| A028 | 84 | 32A, 32B, 32C | Tulathromycin (2.5 mg/kg BW)b | Subcutaneous | 1 | - |
| Chlortetracycline (35 mg/kg diet DM)c | In feed | 1 | 84 | |||
| Chlortetracycline (6 g/head/day)d | In feed | 1 | 22 | |||
| Monensin sodium (25 mg/kg diet DM)e | In feed | 1 | 84 | |||
| A156 | 82 | 50A | Tulathromycin (2.5 mg/kg BW) | Subcutaneous | 1 | - |
| Chlortetracycline (35 mg/kg diet DM) | In feed | 1 | 82 | |||
| Monensin sodium (25 mg/kg diet DM) | In feed | 1 | 82 | |||
| A877 | 86 | 55A | Tulathromycin (2.5 mg/kg BW) | Subcutaneous | 1 | - |
| Chlortetracycline (35 mg/kg diet DM) | In feed | 1 | 86 | |||
| Monensin sodium (25 mg/kg diet DM) | In feed | 1 | 86 | |||
a
All cattle were housed in the same pen and sampled on February 10, 2010.
b
Used for prevention of BRD.
c
Used to prevent liver abscesses.
d
Used to prevent Histophilus somni infection.
e
Used to promote growth and control coccidiosis.