Investigation of infection, genetic evolution and structural characteristics of bovine coronavirus in dairy farms in Hebei, China.

Abstract

Bovine coronavirus (BCoV) is a significant pathogen in dairy cattle, but its strain-specific adaptation and antigenic variability in China are poorly understood. This study investigated the prevalence, genetic evolution, and structural-functional characteristics of the BCoV S1 protein across three large-scale farms over four seasons and five growth stages. A seasonal pattern was observed, with the highest prevalence in autumn, potentially linked to temperature effects on host immunity and viral stability. Infection rates varied by farm, underscoring the influence of management practices. BCoV infection was associated with increased morbidity and mortality in milk-fed calves, resulting in an average weight reduction of 7.2 kg and an additional $30 in feeding costs per calf by 60 days, imposing substantial economic losses. Phylogenetic analysis showed that Chinese BCoV strains form a distinct lineage, indicating regional adaptation. Variations in the S1 protein, particularly within predicted antigenic epitopes, suggest potential antigenic changes that could impact immune recognition and vaccine efficacy. Structural and physicochemical analyses revealed strain-specific differences in charge and hydrophobicity, which may alter immune recognition affinity. These findings highlight the need for ongoing genomic surveillance, enhanced biosecurity, and tailored vaccination strategies to mitigate the economic and health impacts of BCoV.