This study was conducted to identify the risk factors of within-herd transmission of the bovine leukemia virus for the establishment of effective preventive measures of enzootic bovine leucosis (EBL). Out of 139 cooperating farms from 7 prefectures, 110 (79.1%) farms were infected with BLV. We received the completed questionnaire of 90 infected farms. The within-farm seroprevalence was 17.1%, 48.1%, and 68.5% for the 25th, 50th, and 75th percentiles, respectively. Statistical analyses of the withinfarm seroprevalence and farm factors implicated a loose housing system, dehorning, and a large number of horseflies in summer as risk factors (p = 0.03, <0.01, and 0.01, respectively). Feeding newborn calves colostrum from their dams was found to be a protective factor against within-farm transmission of BLV on infected farms (p = 0.03). Control of EBL in infected dairy farms in Japan will be improved by focusing particularly on these risk and protective factors.
(Epidemiological Research Team, TEL +81-29-838-7708)
Reference:
Kobayashi, S. et al. (2010) BMC Veterinary Research. 6:1.
