Epidemiologic concerns relative to in vivo and in vitro production of livestock embryos

Evidence indicates low potential for transmission of pathogens with in vivo -derived embryos of cattle when appropriate precautions are taken. In appar ent contrast, results of research with in vive-derived embryos of small rum inants and swine and with in vitro-derived embryos of cattle suggest a grea ter tendency for their association with pathogens after artificial exposure . However, regardless of donor species, investigations involving collection of embryos from artificially or naturally infected animals and assessment of health of recipients and offspring after transfer of these embryos have indicated low potential for transmitting disease. In this paper, results of embryo-pathogen research are summarized, emphasiz ing potential for spread of pathogens under natural circumstances. Also, sa fe embryo handling practices and their application to multiple species are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.