Foot-and-mouth disease virus in semen of bulls and its transmission by artificial insemination

Abstract

Semen from 16 bulls experimentally infected with foot-and-mouth disease virus (FMDV) was examined for virus content and its ability to produce FMD in heifers by artificial insemination. FMDV appeared in semen of 2 bulls as early as 12 hours after inoculation and, thereafter, virus was found in 58 of 71 semen samples from 16 bulls for as long as 10 days. The highest titer in semen was 105.8 mouse LD50/ml and the titer usually was higher than in urine and sometimes higher than in blood samples taken simultaneously. Five of 16 heifers artificially inseminated with semen from infected bulls and 5 of 10 heifers inseminated with FMDV in various diluents developed FMD. It was concluded that semen of bulls could contain FMDV prior to signs of illness and that the disease could be transmitted by artificial insemination. The dilution and freezing techniques commonly used to preserve semen also favor survival of FMDV. The virus in semen is primarily in the fluid portion, but antiserum added to semen could not be relied upon to eliminate it. The semen of some FMD convalescent bulls apparently contains antibodies. © 1968 Springer-Verlag.