Non-infectivity of semen from bulls infected with bovine leukosis virus

Semen and serum were obtained from four bovine leukosis virus (BLV) infected bulls from each of eight bull studs. The samples from the 32 bulls were frozen and stored in liquid nitrogen for subsequent testing. The sera were tested for antibodies to BLV by the agar gel immunodiffusion (AGID) method. Thirty of the bulls were found to be infected with BLV. Pairs of sheep were intraperitoneally inoculated with semen pools of the four bulls from each bull stud. None of the sheep developed antibodies to BLV. A later challenge with BLV infected lymphocytes resulted in the infection of all challenged sheep indicating that they were susceptible to BLV infection. The results provide evidence that transmission of BLV via leukocyte free semen from BLV infected bulls does not occur.