For the development of disease prevention and intervention strategies, a better understanding
of the dynamics and interactions within cervical bacterial communities in both healthy
cows and cows with metritis is required. Understanding the complexity and ecology
of microorganisms in the vagina of dairy cows with metritis and during different physiological
phases is critical for developing strategies to balance microorganism content. To
gain deeper insight into fluctuations within the cervical microbiota, swab samples
were collected from 40 Holstein dairy cows, and16S rDNA amplicon sequencing was used
to analyze cervical bacterial diversity. Meanwhile, vaginal bacterial composition
was analyzed during different physiological phases, including the formative (CF),
gestational (CG), and postpartum (CP) stages, and in cows with metritis (CM). The
results revealed a complex profile with extensive differences in the cervical bacterial
composition. A total of 678,043clean 16S rDNA V4-V6 reads were gained, and 1877 Operational
Taxonomic Units (OTUs) were observed after calculation. At both the phylum and genus
levels, the top 10 bacteria by percentage were the same when comparing the CF, CG,
and CP groups of cows, with some variation in abundance. At the phylum level, the
cervical microbial community in the CF, CG, and CP groups included mainly Firmicutes,
which accounted for 39.3%, 48.3%, and 49.6% of the total microbial composition of
each group, respectively. However, the cervical bacterial community in the CM group
consisted of mostly Bacteroidetes, which accounted for 72.6% of the total microbial
composition. The second major bacterial community in the CF and CG groups of cows
was Proteobacteria, which accounted for 28.3%and 30.1% of the total microbial compositions
of these groups, respectively, while the second major bacterial community in the CP
group was Bacteroidetes (23.5%). However, in the CM group, the second major bacterial
community was Fusobacteria, which accounted for18.0% of the total microbial composition.
At the genus level, the cervical bacterial community in the CM group of cows was dominated
by Porphyromonas(44.4%) and Fusobacterium(12.1%), while Porphyromonas accounted for
only 1.3%, 1.1%, and 1.4% of the total microbial compositions of the CF, CG, and CP
groups, respectively. Likewise, Fusobacterium accounted for 2.3%, 0.7%, and 4.7% of
the total microbial compositions of the CF, CG, and CP groups, respectively. The results
demonstrate that cervical bacterial diversity decreases in cows with metritis and
that the predominant bacterial genera are Porphyromonas and Fusobacterium. Cervical
bacterial diversity was rich in all observed physiological phases, and the predominant
bacterial phylum was Firmicutes. Pregnancy had little effect on the cervical bacterial
community; however, there were increases in the abundances of pathogenic species in
postpartum cows. Cervical bacterial diversity decreased in cows with metritis, however,
due to the highly dynamic and complex course of metritis, the relationship between
cervical bacterial diversity and metritis requires further investigation.