Bovine leukemia virus (BLV) cause bovine lymphoma, the most common neoplasia of cattle. attack lymphatic cells
Transmitted by transfer of blood, consumption of colostrum or milk and transfer across the placenta during pregnancy. Biting flies (horse and deer flies) are a proposed mechanism of transfer, but the results are not conclusive, but increasing fly prevention may reduce BLV. Diagnosis is made via serology testing.
To control BLV on-farm
• Use individual sterile needles for transdermal injection or blood collection.
Disinfect tattoo equipment between animals.
Use electric dehorners, or disinfect dehorning equipment between animals.
Replace examination gloves and sleeves between animals.
Use milk replacer to feed preweaned calves.
Heat-treat or pasteurize colostrum.
Use BLV-seronegative recipients for embryo transfer.
Wash and rinse instruments in warm water, then submerge in an appropriate disinfectant
Source of info - Large Animal Internal Medicine 4th edition ; author - Bradford P. Smith
hope this helps , if looking for more info, i can steer you in the right direction
JWW