INSEMINATION OF CATTLE WITH SEMEN FROM A BULL TRANSIENTLY INFECTED WITH PESTIVIRUS

When 73 heifers (60 of which were seronegative to pestivirus) were ins eminated with pestivirus-contaminated semen from a transiently infecte d bull, the conception rate to a single insemination was found to be n ormal (65 per cent). Only three animals became systemically infected, as determined by viraemia and seroconversion. Pestiviru was isolated f rom the reproductive tracts of two of these heifers when they were sla ughtered 42 or 43 days after insemination, Although the initial incide nce of infection was low, a cycle of secondary transmission occurred a pproximately 29 days after insemination, with a further eight heifers (all seronegative) becoming infected from one group of 11 seronegative and four seropositive animals.