Table 2.
Mannheimia haemolytica isolation at arrival, week 3, and week 10 across 4 separate trials.
| Trial | TxGroup | NArr | MHArr n (%) | MDRArr n (%) | NWK3 | MHWK3 n (%)** | MDRWK3 n (%)** | NWK10 | MHWK10 n (%) | MDRWK10 n (%) |
|---|---|---|---|---|---|---|---|---|---|---|
| Fall 2019 | META | 41 | 10 (24)a | 0 (0) | 41 | 20 (49) | 0 (0) | 41 | 2 (5) | 0 (0) |
| NO META | 41 | 2 (4.9)b | 0 (0) | 41 | 12 (29) | 0 (0) | 41 | 2 (5) | 0 (0) | |
| All | 82 | 12 (15)c | 0 (0)e | 82 | 32 (39)gh | 0 (0)m | 82 | 4 (5)o | 0 (0)q | |
| Fall 2020 | META | 42 | 8 (19) | 3 (7.1) | 41 | 24 (58) | 24 (59)i | 40 | 6 (15) | 3 (8) |
| NO META | 41 | 9 (22) | 1 (2.4) | 39 | 20 (51) | 4 (10)j | 39 | 2 (5) | 0 (0) | |
| All | 83 | 17 (20)c | 4 (4.8)ef | 80 | 44 (55)g | 28 (35)n | 79 | 8 (10)op | 3 (4)qr | |
| Spring 2021 | META | 42 | 2 (4.8) | 0 (0) | 40 | 15 (38) | 15 (38)k | 38 | 9 (24) | 7 (18) |
| NO META | 40 | 5 (12) | 0 (0) | 36 | 7 (19) | 1 (3)l | 33 | 5 (15) | 1 (3) | |
| All | 82 | 7 (8.5)c | 0 (0)e | 76 | 22 (29)h | 16 (21)n | 71 | 14 (20)p | 8 (11)r | |
| Fall 2021 | META | 42 | 19 (45) | 5 (12) | 42 | 18 (43) | 17 (40) | 42 | 6 (14) | 2 (5) |
| NO META | 42 | 17 (40) | 8 (19) | 41 | 22 (54) | 8 (20) | 40 | 4 (10) | 1 (3) | |
| All | 84 | 36 (43)d | 13 (16)f | 83 | 40 (48)g | 25 (30)n | 82 | 10 (12)op | 3 (4)qr | |
| Overall | META | 167 | 39 (29) | 8 (4.8) | 164 | 77 (47) | 56 (34) | 161 | 23 (14) | 12 (7) |
| NO META | 164 | 33 (20) | 9 (5.5) | 157 | 61 (39) | 13 (8) | 153 | 13 (8) | 2 (1) | |
| All | 331 | 72 (22) | 17 (5.1) | 321 | 138 (43) | 69 (21)* | 321 | 36 (11) | 14 (4)* |
An asterisk (*) in the ‘Overall’ row represents that there was an overall statistical difference between META and NO META TxGroups (χ2 test, p < 0.05). A double asterisk (**) in the header indicates there was a statistically significant difference between a measurement compared to arrival (McNemar’s χ2 test, p < 0.0001). Values with different superscripts in the same column of the ‘META’ or ‘NO META’ rows represent a statistical difference between TxGroups within Trial (ab, χ2, p < 0.05). Values with different superscripts in the same column of the ‘All’ rows represent a statistically significant difference among Trials (cd, ef, gh, mn, op, or qr Pairwise Fisher’s Exact test with Benjamini-Hochberg adjustment, p < 0.05). MH, Mannheimia haemolytica; MDR, multi-drug resistant; Arr, arrival; WK3, week 3; WK10, week 10; N, number of animals sampled; META, tulathromycin metaphylaxis; NO META, no tulathromycin metaphylaxis; TxGroup, treatment group. Percentage of MH isolated is based on total animals sampled. Percentage of MDR is based on total animals sampled.