Progesterone-controlled internal drug release–based estrous synchronization induces vaginal dysbiosis and enrichment of potential pathogens in Braford heifers
Year: 2025
Type: article
Abstract: Objective: To evaluate the effects of an estrus synchronization program on the resident microbial population of the vagina in Braford heifers. Methods: Nulliparous Braford heifers were enrolled in a 9-day progesterone-controlled internal drug release-based estrous synchronization protocol. Vaginal swabs were collected on day (D) 0 and D11 of the synchronization protocol and again on D60 to profile changes in vaginal bacterial communities though 16S ribosomal DNA gene sequencing. Results: Analysis of samples from 10 heifers revealed that the most abundant phyla were the Proteobacteria, Firmicutes, Bacteroidetes, Tenericutes, Fusobacteria, and Actinobacteria. Principal coordinate analysis showed significant differentiation among the vaginal profiles of the microbial communities at D11 compared to D0 and D60. The bacterial clustering may be due to estrous synchronization. Significant differences were observed at the genus level. The relative abundances of known endometrial pathogens Fusobacterium, Helcococcus, Ureaplasma, and Leptotrichiaceae significantly increased from D0 to D11. Conclusions: This study describes, for the first time, transient changes in the diversity of the vaginal microbiota of Braford heifers in response to estrus manipulations. The presence (or absence) of certain recognized pathogens, such as Fusobacterium, Helcococcus, and Ureaplasma, may negatively affect reproductive health, justifying further investigation. Clinical Relevance: These results may help in advances of the diagnosis and treatment of infertility.
Language: English
Subfield: Agronomy and Crop Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W4411372290