A case of an embryo transfer calf infected with bovine leukemia virus fromthe recipient cow

A case was discovered where the embryo transfer (ET) calf had been infected with bovine leukemia virus (BLV) from the recipient cow. The embryo was tr ansferred from the BLV-uninfected donor cow to the recipient cow. However, the BLV test had not been performed to the recipient cow before ET was perf ormed. The ET calf was raised in a calf hatch from birth to 1-month old and was given the recipient cow's colostrum and milk artificially. The ET calf was raised with the two other calves from a 1-month old to a 6-month old. The BLV rest was performed to the ET calf by agar gel precipitation (AGP) a nd passive haemagglutination (PHA) assay when the ET calf was 6 months old. Because the ET calf was positive, the BLV test was performed to the recipi ent cow, the two other calves raised with the ET calf and the two dams of t he two other carves. Because the recipient cow only was positive at the tim e of the first test, we judged that the ET calf had been infected with BLV from the recipient cow. The importance of the BLV test being carried out on the recipient cow for the prevention of enzootic bovine leukemia in a case of ET was recognised.