Comparison of postweaning bovine respiratory disease treatment rates between non-vaccinated control beef calves and calves variably primed and boosted using commercially available bovine coronavirus vaccines.

OBJECTIVE

Bovine respiratory disease (BRD) and overall postweaning treatment rates were compared among 3 groups of calves either differentially primed and boosted with commercially available bovine coronavirus (BCoV) vaccine or not vaccinated against BCoV.

ANIMALS

Commercial heifer and steer beef calves born in April and May 2022.

PROCEDURE

In June 2022, calves were randomly enrolled into 3 treatment groups. Those in 2 groups [V1 ( = 160) and V2 ( = 160)] were administered a mucosal priming dose of 1 of 2 commercial BCoV vaccines; those in the 3rd group [CTL ( = 151)] were unvaccinated against BCoV. The V1 and V2 groups were boosted by intramuscular injection pre-weaning with the same vaccine used for priming. Weaning occurred 3 wk after the last preweaning processing day. Ranch staff used a BRD case definition provided by their herd veterinarian to identify, treat, and record treatments for 45 d post-weaning.

RESULTS

Postweaning BRD treatment rates for V1, V2, and CTL were 7%, 9%, and 14%, respectively. The CTL calves had 2.2× greater odds of receiving treatment for BRD than V1 calves. There were no differences in odds of treatment between CTL and V2 calves or V1 and V2 calves.

CONCLUSION

In a herd with previously diagnosed BCoV BRD cases, prime-boost vaccination of calves is associated with a difference in odds of BRD treatment post-weaning compared to not vaccinating calves against BCoV.

CLINICAL RELEVANCE

Prime-boost vaccination with commercial BCoV vaccine may be an important management tool for herds with known BCoV BRD outbreaks.