| Abstrakt: |
Blood samples from 188 bulls, raised in wetland and floodplain areas, without control reproductive status and health, aged 2 to 15 years, of Murrah and Mediterranean breeds and its crossbred types were evaluated for the presence of antibodies to HBV-1, by testing neutralization. Also it were obtained in 51 semen samples, and analyzed by RT-PCR. All farms had positive animals, and in 155 (82,4%) of the animals blood samples tested among 188 males were serologically positive. Among the Mediterranean and Murrah breeds and their crossbred types showed a statistical significant difference in prevalence (p <0.05). There was influence of body condition scorer (BCS) in the prevalence of bulls serologically positive, and the good BCS animals showed a higher prevalence of the disease when compared to the animals with regular BCS. The prevalence according to age showed a significant difference (p <0.0001) among two years old animals and more than two years old bulls, with a progressively increasing rates of infection with advancing age. The prevalence in the Amapá State was significantly higher than in the Pará State. Through the analysis of the neutralizing antibodies distribution, it was observed a large frequency of high titers. In spite of the high titers observed most animals with titration 128, occurring in the Amapá State. Furthermore, all the 51 semen samples were negative in the test of RT-PCR. [ABSTRACT FROM AUTHOR] |
