Table 2.
Model adjusted means and standard errors of the mean (SEM) for health and antimicrobial use outcomes of steers and heifers at medium risk for bovine respiratory disease (BRD) that received metaphylaxis (META) or a pull-and-treat (PT) health program for BRD *.
| Item | PT | META | p-Value |
|---|---|---|---|
| All morbidity †, % (SEM) | |||
| First treatment | 18.75 (2.967) | 9.44 (1.755) | <0.01 |
| Second treatment | 2.89 (1.108) | 1.67 (0.686) | 0.06 |
| Third treatment | 1.13 (0.431) | 0.60 (0.273) | 0.17 |
| Mean treatment count ⸙, n/100 animals (SEM) | |||
| BRD | 20.26 (3.737) | 9.15 (1.805) | <0.01 |
| Non-BRD respiratory disease | 0.42 (0.230) | 0.78 (0.377) | 0.21 |
| Musculoskeletal/trauma | 0.64 (0.282) | 0.50 (0.237) | 0.63 |
| Other | 1.20 (0.425) | 1.13 (0.405) | 0.86 |
| Total | 22.45 (4.142) | 11.78 (2.273) | <0.01 |
| BRD morbidity, % (SEM) | |||
| First treatment | 17.18 (2.927) | 7.32 (1.498) | <0.01 |
| Second treatment | 2.41 (0.841) | 1.24 (0.486) | 0.05 |
| Third treatment | 0.97 (0.401) | 0.52 (0.254) | 0.21 |
| BRD AMD ‡/animal enrolled, mean (SEM) | 0.21 (0.029) | 1.10 (0.138) | <0.01 |
| BRD AMD ‡/100 kg HCW §, mean (SEM) | 0.06 (0.009) | 0.30 (0.040) | <0.01 |
| Animals removed from trial, % (SEM) | |||
| BRD | 1.05 (0.403) | 0.72 (0.303) | 0.35 |
| Other | 0.55 (0.242) | 1.01 (0.366) | 0.21 |
| Total | 1.55 (0.535) | 1.62 (0.555) | 0.89 |
| Mortality, % (SEM) | |||
| BRD | 0.73 (0.341) | 0.44 (0.234) | 0.34 |
| Other | 1.44 (0.457) | 0.56 (0.231) | 0.04 |
| Total | 2.53 (0.503) | 1.15 (0.317) | 0.03 |
| Total fallouts ⸕, % (SEM) | 3.91 (0.953) | 2.71 (0.708) | 0.10 |
* Trial was conducted as a randomized complete block design at two feedlots in Kansas and Nebraska, USA, using medium-risk steer or heifer blocks. A total of 1544 heifers and 822 steers were randomly allocated to one of two pens within sex and feedlot to form a block, and pens were randomly assigned to treatment (PT or META). Tulathromycin was administered to all META cattle at initial processing, while PT cattle received tulathromycin for first treatment of clinical BRD. Subsequent antimicrobials used for treatment of clinical BRD were identical in their order and type for both treatments. A total of 16 pens with eight treatment replications were enrolled in the trial. † All treatment categories combined. ‡ AMD = antimicrobial doses. § HCW = hot carcass weight. ⸙ Total animals pulled for treatment within a pen per category; includes pulls from cattle treated multiple times. ⸕ Fallouts = all animals removed from the trial plus all mortalities.