Inquérito sorológico da infecção por herpesvírus bovino 1 (bohv-1) em propriedades do estado de Alagoas

Abstract

Cattle farming is important for Brazil, which reached first place in the world ranking in 2020, with 217 million head of cattle. In 2021, according to the IBGE, Alagoas remained in twenty-second place in effective herd, totaling 1,321,236 head of cattle. Among some of the factors that can affect the productivity of the cattle herd, there is infection by bovine herpesvirus 1 (BoHV-1), which has the ability to reach latency and affect the reproduction of these animals. BoHV-1 is a virus widely distributed throughout Brazil, affecting reproductive management and beef and dairy cattle farming. The forms of transmission of this pathogen are through the respiratory tract, as well as the genital tract, through direct contact during intercourse and in semen contaminated by the virus. Due to the diseases caused to the health of the animal and the production losses on the properties, it is necessary to analyze the prevalence of the virus in the herds of the state. The objectives of this study were to analyze the frequency of BoHV-1 and associate it with productive management in farms from Alagoas state. A total of 208 blood serum samples were collected from cattle herds distributed across farms in five municipalities (Viçosa, Pão de Açúcar, Santana do Ipanema, Chã-Preta, and Olho D’água Grande) in the state of Alagoas, located in the regions of Zona da Mata, Sertão, and Agreste, from 2022 to 2023. After seroneutralization tests, all farms tested positive for BoHV-1, and the overall prevalence was 77.8% (162/208), with antibody titers ranging from 2 to 128. In analyses per farm, seropositive animals ranged from 33.4% to 100%. The farm P-2 presented 100% of positive animals, and 81.0% of titers were considered high. This farm proved to be the only one that uses the open farm for entrance of new bovines. In contrast, P-3 showed 66.7% of seronegative animals. Regarding the questionnaire, none of the properties stated that they carried out quarantine. All properties stated that they carried out natural mating and, additionally, two properties stated that they used artificial insemination. Three properties stated that they used replacement bulls. In this study, it was possible to identify for the first time the presence of the virus circulating on five farms from the state of Alagoas.