Prevalence of antibodies against bovine leukemia virus in dairy cattle of Toledo, Paraná, Brazil

Abstract

The enzootic bovine leukosis is a viral disease caused by the bovine leukemia virus (BLV), an oncogenic retrovirus. The disease is widespread in herds, and dairy cattle, due to the intensive management, are the most affected. The growing importance of the international cattle trade, semen, and embryos has required the sanitary certification for the BLV, and the economic impact of the enzootic bovine leukosis is mainly due to the reduction of the milk production. The aim of this study was to determine the prevalence of antibody antiBLV in dairy cattle from Toledo municipality. Fifty-eight rural properties were visited, and blood samples were collected from 390 dairy cattle. The agar gel immunodiffusion (AGID) was used to detect the antibodies against the viral agent. Of the samples analyzed, 34.4% (134/390) showed antibodies against the bovine leukosis. Positive animals were distributed in 63.9% (37/58) of the visited properties. The viral infection is widespread in dairy cattle from Toledo. Therefore, there is a need for adequate control and prevention measures for enzootic bovine leukosis. Serological tests and a constant veterinary follow-up, aiming at the gradual sanitary control of the herds, are a good tool for the control and/or eradication of the disease.