The nasopharyngeal microbiota of beef cattle before and after transport to a feedlot

Holman, Devin B.; Timsit, Edouard; Amat, Samat; Abbott, D. Wade; Buret, Andre G.; Alexander, Trevor W.

In the present study, we used 16S rRNA gene highthroughput sequencing to characterize the NP microbiota of beef cattle heifers that were transported to a feedlot from a closed herd that was regularly tested to be free of contagious diseases. We used a disease-free herd because the calves all had a similar genetic background, and were not exposed to potential perturbations such as antimicrobial and vaccine administration. We also monitored the cattle for the presence of the BRDassociated bacteria M. haemolytica, P. multocida, and H. somni using culture-based methods. It was hypothesized, based on previous research [1, 3] , that cattle would be exposed to novel microorganisms in the feedlot environment resulting in significant changes in their NP microbiota over a 14-d period.