Bovine leukemia virus transmission by dehorning in dairy heifers

Abstract

In a commercial dairy, heifers dehorned by the Barnes gouge method without rinsing in disinfectant solution and not cauterizing had significantly more heifers (50%) developing antibodies to BLV, as measured by agar-gel immunodiffusion, three months after dehorning than calves not dehorned (14%). With the demonstration of this mode of transmission of BLV in the herd, the practice of gouge dehorning was discontinued and electrical dehorning at 6 to 12 weeks of age instituted. The entire herd is presently being bled at 6-month intervals to determine whether BLV infection will be delayed in time or eliminated.