Vaccination is a widely adopted measure to prevent diseases. but the process of immunization can induce a substantial stress response. This study aimed to investigate the impact of a combined Mycoplasma bovis-BoHV-1 vaccine on the upper respiratory tract microbiome and BRD-associated pathogens in calves. as well as to evaluate the effects of potential interventions. https://4thmoontoyers.shop/product-category/moc/