This study was performed in order to determine the frequency of Bovine Herpesvirus 1 (BoHV-1), and the main factors related to the frequency of the infection in dairy cows not vaccinated against BoHV-1 from the Maranhense Amazon region, Brazil. Serum samples from 40 ranches were submitted to indirect ELISA test for detection of BoHV-1 antibodies. An epidemiological questionnaire was applied for each herd to investigate variables that could be associated with this infection. From 400 serum samples examined, 69.25% (n = 277) in 100% (n = 40) of the herds were positive for ELISA. Variables identified as risk factors such of age range of 3-7 years, absence of veterinary assistance and respiratory signs presented a statistical significance (P < 0.05) associated to BoHV-1 infection. These results indicate that BoHV-1 infection is high in the region studied and that factors related to characteristics of the ranches and to the livestock management practices were associated with the risk of infection by BoHV-1.
BoHV-1; antibodies; ELISA; dairy cows; odds ratio