Seroprevalence, Dual Seropositivity, and Associated Risk Factors of BVDV and BoHV-1 in Dual-Purpose Cattle from the Colombian Eastern Plains.

Bovine viral diarrhea virus (BVDV) and bovine herpesvirus type 1 (BoHV-1) are major pathogens affecting cattle worldwide, leading to significant economic losses in livestock production systems. This study aimed to estimate the seroprevalence and dual seropositivity of both viruses in dual-purpose cattle in Villavicencio, Colombia. A total of 1000 serum samples were collected from cattle across 30 farms and analyzed using ELISA. Seroprevalence for BVDV ranged from 0.0% to 78.7%, while BoHV-1 ranged from 0.0% to 100.0%. Dual seropositivity with both viruses was observed at the farm level, ranging from 0.0% to 52.2%. At the herd level, 26.7% (8/30) of the farms were seronegative for BVDV (95% CI: 14.2-44.5%), whereas only 3.3% (1/30) were seronegative for BoHV-1 (95% CI: 0.6-16.7%). Additionally, seven farms (23.3%) were simultaneously seronegative for both BVDV and BoHV-1. Overall, the findings demonstrate widespread exposure and non-random concurrent seropositivity of both viruses, highlighting the importance of herd management, biosecurity, and animal movement in shaping infection dynamics in dual-purpose cattle systems. Management practices, animal movement, and environmental factors were significantly associated with seropositivity.