Incomplete reporting in randomized controlled trials of bovine respiratory disease vaccines in feedlot cattle

We evaluated bovine respiratory disease vaccine trials in feedlot cattle and found that most (19 of 34 [56%]) publications (describing 26 of 43 [60%] trials) labeled the control group as "unvaccinated" or similar terms even when all cattle in the trial received vaccine(s) at feedlot arrival. Additionally, 38 of 44 (86%) publications (describing 31 of 53 [58%] trials) reported statistical comparisons of bovine respiratory disease vaccines that did not mention the respiratory vaccines that all cattle received at feedlot arrival. Trial authors should report animal health products given to all cattle in a trial, in the abstract, methods, and results sections, to prevent misinterpretation of the actual comparisons investigated.