Providing a rest stop during transportation affects the respiratory bacterial microbiota of beef cattle

This study investigated the effects of a rest stop during transportation on the nasopharyngeal (NP) microbiota of beef cattle. Two separate trials (N = 80 calves per trial) were conducted with treatment groups assigned to rest stop durations of 12 h (Study 1) and 8 h (Study 2), being compared to control animals without a rest stop. In Study 1, cattle were acclimated to a feedlot prior to transportation while in Study 2, cattle were unacclimated. Following transportation and a rest interval, calves were placed into a feedlot and sampled by NP swab periodically for 28 days. Across treatments and time, the most abundant genera included Mycoplasma, Histophilus, Mannheimia, Pasteurella, Moraxella, and Acinetobacter. In both studies, microbial diversity and structure were not affected by providing a rest stop. However, NP swabs from more sampling time points had elevated levels of the BRD-associated genera Mannheimia, Histophilus, and Mycoplasma when the microbiota of calves provided rest were compared to animals given no rest