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

Abstract

BackgroundThe nasopharyngeal (NP) microbiota plays an important role in bovine health, comprising a rich and diverse microbial community. The nasopharynx is also the niche for potentially pathogenic agents which are associated with bovine respiratory disease (BRD), a serious and costly illness in feedlot cattle. We used 14 beef heifers from a closed and disease-free herd to assess the dynamics of the NP microbiota of cattle that are transported to a feedlot. Cattle were sampled prior to transport to the feedlot (day 0) and at days 2, 7, and 14.ResultsThe structure of the NP microbiota changed significantly over the course of the study, with the largest shift occurring between day 0 (prior to transport) and day 2 (P < 0.001). Phylogenetic diversity and richness increased following feedlot placement (day 2; P < 0.05). The genera Pasteurella, Bacillus, and Proteus were enriched at day 0, Streptococcus and Acinetobacter at day 2, Bifidobacterium at day 7, and Mycoplasma at day 14. The functional potential of the NP microbiota was assessed using PICRUSt, revealing that replication and repair, as well as translation pathways, were more relatively abundant in day 14 samples. These differences were driven mostly by Mycoplasma. Although eight cattle were culture-positive for the BRD-associated bacterium Pasteurella multocida at one or more sampling times, none were culture-positive for Mannheimia haemolytica or Histophilus somni.ConclusionsThis study investigated the effect that feedlot placement has on the NP microbiota of beef cattle over a 14-d period. Within two days of transport to the feedlot, the NP microbiota changed significantly, increasing in both phylogenetic diversity and richness. These results demonstrate that there is an abrupt shift in the NP microbiota of cattle after transportation to a feedlot. This may have importance for understanding why cattle are most susceptible to BRD after feedlot placement.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-017-0978-6) contains supplementary material, which is available to authorized users.

Prevalence of Pathogens Related to Bovine Respiratory Disease Before and After Transportation in Beef Steers: Preliminary Results

“…It is important to highlight that, in our study, DNS collected from the animals at the local farm were positive only for BCoV, thus the epidemiological status of the herd at arrival may be one of the reasons for the higher prevalence of this virus found in the DNS at T1. This datum supports the theory that the epidemiological status of arrival farms should be considered as a possible risk factor of BRD [4,20].…”

“…As already demonstrated [4], the nasal microbiota tested in the present study showed changes when the DNS before the transport and after the arrival at the feedlot in Italy were compared. Although the cattle involved in this study only originated from France feedlots, constraining our findings, the study has several strengths and points of interest.…”

“…Overall, it is evident that the bovine nasopharyngeal microbiota undergoes changes following arrival at the feedlot and its evolution in beef cattle after arrival at a feedlot was also described by other researchers [4,20]. The feedlot environment, and its associated stressors, may provide conditions that allow for the proliferation of M. bovis in the nasopharynx within the first 14 days of feedlot placement [4].…”

“…The syndrome has a multifactorial etiology, including infectious agents, host and environmental factors, with particular emphasis on transport stress. The latter is indeed responsible for physiological changes that favor pathogen proliferation and invasion of tissues by opportunistic pathogens [1][2][3][4][5]. Viruses and stress-related behavior interfere with the mucociliary clearance of the respiratory tract and dysregulate the tracheal antimicrobial peptides of the innate defenses, allowing opportunistic bacteria to cause pulmonary infections [2,6].…”

Bovine respiratory syncytial virus infection enhances Pasteurella multocida adherence on respiratory epithelial cells

“…According to our preliminary findings based on the BRDC gene detection from respiratory samples, paired virus and bacteria were detected and PM was the most common bacterial agent (unpublished data). PM is common in the nasopharynx of cattle (Timsit et al, 2016;Holman et al, 2017), but not all calves harboring the bacterium develop pneumonia (Autio et al, 2007;Holman et al, 2017). However, although PM appears to be part of the normal flora, it can contribute to pneumonia when cattle become stressed and/or infected by a respiratory virus (Dabo et al, 2007).…”