Prevalence and Risk Factors of Bovine Viral Diarrhea Virus Antibodies in Dairy Herds of Bangladesh.

A cross-sectional study was conducted in Bangladesh from January 2023 to December 2024 to assess the prevalence of BVDV antibodies and associated risk factors in dairy herds. Initially, 138 bulk milk samples were collected from herds across 14 districts and screened using a commercial ELISA for BVDV antibodies. Subsequently, 767 individual milk samples were tested from cows in herds that screened positive. The overall herd-level seroprevalence was 72.5% (95% CI: 64.1-79.6), while the cow-level seroprevalence was 93.3% (95% CI: 91.3-94.9%). Within-herd seroprevalence varied from 81.8% to 100%. Herds with more than 70 cows had 31.95 times higher odds of BVDV seropositivity than those with 13-23 cows. BVD seroprevalence was significantly higher in the third, fifth, and eighth semen sources compared to the reference source. Cows older than 8 years had 4.53 times higher odds of seropositivity than those aged up to 4 years. Cows in thin physical condition had 13.02 times higher odds of seropositivity than those in normal condition. Conversely, cows producing over 8.8 kg of milk daily had a significantly lower seroprevalence of BVDV compared to those producing less than 8.8 kg, with an odds ratio of 0.41 (95% CI: 0.17-0.98). These findings suggest that BVDV exposure is widespread in dairy herds in Bangladesh. Regular serological screening, the use of semen from BVD-free bulls, and prioritizing surveillance for thin cows and low milk producers are essential. Improving nutrition, herd management, and targeted monitoring may help reduce BVDV transmission and improve herd productivity.