Dairy Cattle Infection with Bovine Rotavirus at Different Growth Stages and Its Impact on Health and Productivity.

This study evaluated the prevalence of BRV infection and its impact on the health of dairy cows at different growth stages, with a particular focus on milk-fed calves. BRV was detected in rectal swabs via RT-qPCR. In the total sample of 2400 dairy cows examined at three farms, 103 (4.29%) were found to be positive for BRV. Similarly, of the 480 milk-fed calves, 70 (14.58%) were also found to be positive for BRV. Negative binomial regression analysis revealed that older farms had higher average BRV positivity rates than new farms did and that the BRV positivity rate was higher in autumn than in the other three seasons. Additionally, BRV positivity rates gradually decreased as calf age increased. In milk-fed calves, BRV positivity was positively correlated with morbidity and mortality and negatively correlated with ADG and ADGPR. These findings provide valuable insights for farm management, particularly for older farms, highlighting the detrimental effects of BRV infection on milk-fed calves and underscoring the importance of targeted control strategies to reduce BRV prevalence and optimize dairy production efficiency.