Prevalence of enzootic bovine leukosis in the South Marmara Region and observations of some management practices

Abstract

Seven hundred seventeen cattle, over the age of six months in the South Marmara Region (Bursa, Bahkesir and Canakkale) were tested for the presence of Bovine leukemia Virus (BLV)-antibody with ELISA. Blood and milk samples were taken from 362 and 355 cattle, respectively. Totally, sixty-nine cattle (9.62%) were found to be carriers of antibodies against BLV-gp 51 antigen. The BLV infection rate was found to be 13.25% and 5.91% in the sera and milk samples tested, respectively. The infection rate were determined to be 14.19% in Bursa and 3.52% in Bahkesir, but BLV seropositive cattle were not found in Canakkale. It was observed that the highest infection rate was in the Karacabey provincial region of Bursa. By repeated hematological examinations of seropositive cattle, 30 (43.47%) cattle were found to have persistent lymphocytosis (PL),The infection rate was high in the herd at Karacabey. The total leucocyte count and lymphocyte percantages in the BLV+PL+ group were observed to be higher (P<0.001) than in the BLV- and BLV+PL-groups. The lymphosarcoma form of the infection was not seen in this study. It was noted that larger herds, pooled milk feeding, repeated vaccination and therapeutic procedures, using contamined sleeves and particularly needles caused the increase in EEL. In conclusion, it was determined that BLV infection was high in Nilufer and particularly high in Karacabey-Bursa, and some management practices was effective in reducing the infection rate. it was thought that the BLV infection rate would be decreased by preventing iatrogenic transmission and particularly eliminating the cattle with PL.