Association of prepartum clostridial vaccine administration with mitigation of respiratory and gastrointestinal disorders in calves.

Pathogenic clostridial infections, particularly those involving Clostridium perfringens type A (CpA)-derived alpha-toxin (CpA-α), are a recognized cause of gastrointestinal disorders in young ruminants. However, the potential role of anti-clostridial antibodies in mitigating not only gastrointestinal but also respiratory disorders in calves remains poorly investigated under field conditions. This study evaluated the effects of anti-clostridial antibodies passively transferred from cows vaccinated with a clostridial vaccine (CV) during the prepartum period on gastrointestinal and respiratory disorders in nursing calves. Cows in the CV group were vaccinated at 8 and 4 weeks before parturition, whereas control cows were not. Colostrum intake was verified in calves from both groups. Serum antibody titers against clostridial and bovine respiratory disease (BRD) pathogens were measured. Treatment frequency and fecal consistency were also recorded. Anti-clostridial antibody titers were higher in CV cows and their calves compared to the control group. In the CV group, the number of respiratory treatments in calves showed a decreasing trend from 5 to 8 weeks of age and was significantly lower from 9 to 12 weeks of age. Fecal consistency at 1 week of age was also significantly improved in the CV group. The number of respiratory treatments was negatively correlated with anti-CpA-α antibody titers in calves, but not with anti-BRD titers. These findings suggest that prepartum CV vaccination may help mitigate both respiratory and gastrointestinal disorders in nursing calves, potentially reducing antibiotic use and lowering the risk of antimicrobial resistance in livestock industry.