Table 1.
Mannheimia haemolytica isolation and weight of animals at arrival.
| Trial | TxGroup (n*) | Arrival MH culture n (%) | MDR MH n (%) | Median arrival weight (95% CI) (kg) |
|---|---|---|---|---|
| Fall 2019 | META (41) | 10 (24.4)a | 0 (0) | 228 (215–242) |
| NO META (41) | 2 (4.9)b | 0 (0) | 230 (219–241) | |
| All (82) | 12 (14.6)c | 0 (0)e | 229 (217–241) | |
| Fall 2020 | META (42) | 8 (19.0) | 3 (7.1) | 230 (218–238) |
| NO META (41) | 9 (22.0) | 1 (2.4) | 230 (218–239) | |
| All (83) | 17 (20.5)c | 4 (4.8)ef | 230 (218–239) | |
| Spring 2021 | META (42) | 2 (4.8) | 0 (0) | 232 (219–241) |
| NO META (40) | 5 (12.5) | 0 (0) | 229 (219–244) | |
| All (82) | 7 (8.5)c | 0 (0)e | 230 (219–242) | |
| Fall 2021 | META (42) | 19 (45.2) | 5 (11.9) | 234 (227–249) |
| NO META (42) | 17 (40.5) | 8 (19.0) | 238 (232–246) | |
| All (84) | 36 (42.9)d | 13 (15.5)f | 237 (229–248) | |
| Overall | META (167) | 49 (29.3) | 8 (4.8) | 231 (220–242) |
| NO META (164) | 33 (20.1) | 9 (5.5) | 233 (220–244) | |
| All (331) | 72 (21.8) | 17 (5.1) | 232 (220–242) |
*Group numbers are after removals. 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 or ef, Pairwise Fisher’s Exact test with Benjamini-Hochberg adjustment, p < 0.05). Percentages represent percent of animals. MH, Mannheimia haemolytica; MDR, multi-drug resistant; SD, standard deviation; META, tulathromycin metaphylaxis; NO META, no tulathromycin metaphylaxis; TxGroup, treatment group.