SRP179054 PRJNA508519 Effects of tilmicosin treatment on the nasopharyngeal microbiota of feedlot cattle with respiratory disease The nasopharyngeal (NP) microbiota is believed to be a key player in the health of the upper respiratory tract, and disturbances in the NP microbial communities may contribute to the pathophysiology of bovine respiratory disease (BRD). Interestingly, there have been no studies examining the change of NP microbiota associated with clinical recovery from BRD. The objective of this study was to evaluate the effect of Tilmicosin treatment on the NP microbiota composition, diversity, and predicted functional gene profiles, of BRD affected calves during the first week of clinical recovery. calf respiratory microbiome