Prevention of disease transmission by semen in cattle

To test the safety of semen two approaches can be applied: checking the end product, or continuous surveillance of the bulls before and after semen pr oduction. The first method is examination of semen for the presence of infe ctious agents. This method depends completely on a single investigation and therefore relies only on the sensitivity of the test method. The second me thod is testing the bulls for diseases before and after semen collection, b ased on sequential investigations for the absence of either pathogens or an tibodies against infectious agents. The EBT-Directive 88/407 prescribes tha t bulls in Al stations must be monitored for the absence of diseases, but o nly at 12-monthly intervals, which is a severe disadvantage. Furthermore, t he directive is specific neither in the tests to be carried out nor in the specification of some pathogens (e.g. Campylobacter foetus). A programme is presented based on monthly testing of a limited number of bu lls for the absence of endemic diseases only, on the basis of Hazard Analys is of Critical Control :Points (HACCP). This method only applies to disease s with high transmission rates. Testing some 20% of the animals on a monthl y basis can monitor these highly contagious diseases (e.g. IBR). To monitor BVDV infections, however, monthly testing of all negative animals and seme n culture or semen PCR of animals that have seroconverted for this virus se ems necessary! Endemic diseases with slow transmission rates in bulls do no t suit such a system and can only be monitored on an individual basis. (C) 2000 Elsevier Science B.V. All rights reserved.