Table 5.
Co-isolation patterns of bacteria* recovered from calves at time of first BRD treatment (N = 16 pens).
| Bacterial isolation pattern | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Year | Metaphylaxis | Number Calves | Neg. Culture | MH | PM | HS | MH + PM | MH + HS | PM + HS | MH + PM + HS |
| 2020 | Tulathromycin | 28 | 6 (21%) | 9 (32%) | 0 (0%) | 0 (0%) | 4 (14%) | 5 (18%) | 1 (4%) | 3 (11%) |
| 2021 | Tulathromycin | 13 | 1 (8%) | 6 (46%) | 1 (8%) | 1 (8%) | 2 (15%) | 1 (8%) | 1 (8%) | 0 (0%) |
| 2021 | Oxytetracycline | 89 | 9 (10%) | 31 (35%) | 11 (12%) | 7 (8%) | 13 (15%) | 6 (7%) | 8 (9%) | 4 (4%) |
| All years | All groups | 130 | 16 (12%) | 46 (35%) | 12 (9%) | 8 (6%) | 19 (15%) | 12 (9%) | 10 (8%) | 7 (5%) |
*M. haemolytica, MH; P. multocida, PM; H. somni, HS.