ABSTRACT
Artificial insemination (AI) has proven to be useful for herd improvement, ease of management, venereal disease control, and to capitalize on hybrid vigor through crossbreeding. There are several diseases that may be transmitted through semen, and they are of major concern when bull semen is being considered for use in a country that is free from these diseases. A partial listing of diseases transmitted by semen includes epizootic abortion, tuberculosis, leptospirosis, brucellosis, venereal trichomoniasis, vibriosis, foot-and-mouth disease (FMD), infectious bovine rhinotracheitis (IBR), bovine virus diarrhea, bluetongue, and mycoplasmosis. Some of these disease agents are of more concern than others. Bluetongue virus has been found in the semen of animals for as long as 300 days and IBR for almost 2 yr. FMD virus is also shed in semen. Semen has been found to contain virus hours before the animal exhibits signs of the illness, and this could be particularly dangerous. Virus has also been found in the semen of FMD bulls vaccinated 7 days after exposure to the virus and in the absence of clinical signs of the disease. Semen which contains these viruses may serve as a mechanism for infecting the dam. For these reasons, animal health authorities and stockmen, nationally and internationally, usually support strict standards for control of semen. It is possible that embryo transfer may improve our ability to use new species and breeds of livestock. Before embryo transfer can be used to transfer animals from one continent to another, it will be necessary to study the possibilities of disease transmission by this means. Early results indicate that it may be necessary to study each disease agent in question. Some results are available on bovine leukosis, bluetongue, IBR, and Pseudorabies, and these results will be reviewed.
