This study was performed in order to determine the frequency of bovine viral diarrhea virus (BVDV), and the main factors related to the frequency of the infection in dairy cows not vaccinated against BVDV from Maranhense Amazon region. Serum samples were submitted to an indirect ELISA test for detection of BVDV antibodies. An epidemiological questionnaire was applied for each herd to investigate variables that could beassociated with this infection. Serum samples were collected from 40 farms, with or without clinical signs of BVDV infection. From 400 serum samples examined, 61.5% (n=246) in 95% (n=38) of the herds were positive for ELISA. Variables identified as risk factors such as milk production (1-5L), absence of veterinary assistance, use of natural breeding or natural breeding associated with artificial insemination. These risk factors presented statistical significance (P<0.05) associated to BVDV infection. These results indicate that BVDV infection is high in the studied region and that factors related to the herd characteristic and management were associated with the risk of infection by BVDV.
BVDV; antibodies; ELISA; dairy cows; risk factors
