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



The 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.



This 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.
United States Department of Agriculture, National Animal Disease Center, Agricultural Research Service, Ames, IA, USA.
Devin B
DB
Holman
Department of Production Animal Health, University of Calgary, Calgary, AB, Canada.
Edouard
E
Timsit
Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, AB, T1J 4B1, Canada.
Samat
S
Amat
Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, AB, T1J 4B1, Canada.
D Wade
DW
Abbott
Department of Biological Sciences, University of Calgary, Calgary, AB, Canada.
Andre G
AG
Buret
Lethbridge Research Centre, Agriculture and Agri-Food Canada, 5403 1st Avenue South, Lethbridge, AB, T1J 4B1, Canada. trevor.alexander@agr.gc.ca.
Trevor W
TW
Alexander
D000818:Animals; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D044822:Biodiversity; D048090:Bovine Respiratory Disease Complex / Q000382:microbiology; D002417:Cattle / Q000382:microbiology*; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D006799:Housing, Animal; D064307:Microbiota / Q000235:genetics; D009305:Nasopharynx / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013997:Time Factors
D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
16S rRNA gene; Bovine respiratory disease; Cattle; Feedlot; Livestock; Microbiome; Nasopharyngeal microbiota