Antimicrobial drug use for control and treatment of bovine respiratory disease in US feedlot cattle: A metaanalysis of comparative studies versustulathromycin

摘要

A meta-analysis of studies allowing the calculation of number of antimicrobial treatments needed for control or treatment of bovine respiratory disease (BRD) 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 ofthe 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 [I2 = 89.2%) was at least partlyexplained 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 treatment courses could not be attributed to higher mortality. Raw mean differences in number of antimicrobial treatment courses were -0.229 and -0.303 for control and treatment of BRD, respectively, translating to estimated reductions of 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.