Research Summary - 2
Comparison of tulathromycin versus enrofloxacin for the treatment of bovine respiratory disease following metaphylaxis in US commercial feedlots
| Date/Time: |
9/12/2025
17:30
|
| Author: |
Shane Terrell |
| Clinic: |
Production Animal Consultation |
| City, State, ZIP: |
Scott City, KS 67871 |
Shane Terrell, DVM, PhD
1
;
James Lowe, DVM, MS, DABVP
1
;
Erin Jobman, DVM, MPH
1
;
Dan Thomson, PhD, DVM
1
;
Jessica Newberry, DVM, MS, MBA
2
;
1Production Animal Consultation, 307 S Main, Scott City, KS 67871
2Virbac Corporation, 1308 Glade RD, Elkland, MO 65644
Introduction:
Macrolide antimicrobial drugs are commonly used for treatment and control of bovine respiratory disease (BRD). The objective of this study was to compare the efficacy of tulathromycin and enrofloxacin for treatment of BRD, following metaphylaxis with tulathromycin.
Materials and methods:
A total of 483 beef cattle from 35 lots were enrolled in a randomized controlled study. The study took place at a commercial feedlot in Central Nebraska. Eligible lots included cattle entering the feedlot that weighed 550 +/- 200 lbs. and were deemed high risk for developing BRD. All cattle received Tulissin 100 ® (tulathromycin injectable solution) for metaphylaxis at arrival processing. Enrollment took place at the time of first treatment for BRD. Study cattle did not have pre-existing disease nor comorbidities. Cattle satisfying the study enrollment criteria were randomly assigned to 1 of 2 treatments: Tulissin 100 ® (tulathromycin injectable solution, TUL) or Tenotryl ™ (enrofloxacin injectable solution, TEN). Electronic identification (eID) tags were placed at enrollment and used to match individual carcass data provided by the abattoir. Cattle requiring retreatments followed a uniform treatment regimen with a 4-day post-treatment moratorium. The statistical analysis was performed using SAS Version 9.4 (SAS Institute, Cary, NC). Treatment success, case fatality rate, live performance, and carcass outcomes were compared across treatment groups. Continuous variables were analyzed using linear mixed mode, and binary outcomes were analyzed using generalized mixed models (PROC GLIMMIX). All statistical models included treatment as a fixed effect and lot as the random effect.
Results:
No significant differences (p ≤ 0.05) were observed in treatment success, case fatality rate, and live performance outcomes. Carcass outcomes revealed a significant difference in backfat thickness (p = 0.0334). The effect of treatment did not demonstrate any additional significant effects on carcass outcomes; therefore, we suspect this finding may be an example of Type I Error, an incorrect rejection of a true null hypothesis, and it requires further validation.
Significance:
This study provides treatment data comparing tulathromycin versus enrofloxacin, following metaphylaxis with tulathromycin. The results of this study indicate that there were no significant differences in treatment success, case fatality rate, live performance, and carcass outcomes between treatment groups.
