Antimicrobial drug use for control and treatment of bovine respiratory disease in US feedlot cattle

A meta-analysis of comparative studies versus tulathromycin

Abstract

A meta-analysis of studies allowing the calculation of number of antimicrobial treatments needed for control or treatment of bovine respiratory disease (BRO) was conducted, comparing tulathromycin with other commonly used antimicrobials. Summary effect size (Hedges' g) was the standardized mean difference in number of treatments, with raw mean differences being calculated to estimate the clinical impact of results. Further analyses included subgroup metaanalyses, meta-regression, and meta-analysis of the relative risk (RR) of mortality. Tulathromycin as first-choice antibiotic was associated with fewer antimicrobial treatment courses than comparator products (Hedges' g = -0.374; P < 0.0001). Substantial heterogeneity (/2 = 89.2%) was at least partly explained by subgroup analyses of comparator substance and study sponsor. The risk of mortality following tulathromycin treatment compared with comparator antimicrobials was reduced by half (RR= 0.512, P < 0.0001); accordingly, fewer between 0.8 and 1.8 million antibiotic courses per year in US feedlots when tulathromycin is used as first choice for metaphylaxis or treatment of BRD.