Effects of Vaccination and Interventions on Nasal Microbiome and BRD-Associated Pathogens in Calves

This study aimed to investigate the impact of a combined M. 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. The results showed that the percentage of Pasteurella species in the upper respiratory tract was elevated in calves after vaccination without intervention, and Pasteurella multocida was activated and proliferated.

Interestingly, none of the three interventions (Sodium selenite-vitamin E, Astragalus polysaccharide and Ceftiofur sodium) affected antibody production after immunization. The administration of sodium selenite-vitamin E and astragalus polysaccharide reduced serum levels of cortisol and malondialdehyde, increased glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and alleviated the proliferation of Pasteurella multocida.