Livestock Production Science 62 2000 237–251 www.elsevier.com locate livprodsci
Preventing disease transmission through the transfer of in-vivo- derived bovine embryos
D.A. Stringfellow , M.D. Givens
Department of Pathobiology , College of Veterinary Medicine, Auburn University, Auburn, AL 36849-5519, USA
Abstract
Investigation and experience have demonstrated that movement of in-vivo-derived bovine embryos can be accomplished while effectively limiting spread of infectious disease between populations of cattle. Experimental and theoretical
justifications of current strategies for production of specific-pathogen-free, in-vivo-derived embryos are reviewed. Hazards of spreading bovine viral diarrhea virus via in-vivo-derived embryos are dealt with specifically. It is concluded that established
sanitary procedures for producing pathogen-free, in-vivo-derived embryos are efficacious if the ethical and technical excellence of those performing the procedures can be assured.
2000 Elsevier Science B.V. All rights reserved.
Keywords : Bovine embryo; Specific-pathogen-free embryo; Bovine viral diarrhea virus
1. Introduction might provide a new mode for transmission of
disease. Early concerns about transfer of infectious Introduction of postnatal animals and semen were
agents with embryos were based on embryo–patho- traditional methods used to replenish and improve
gen observations that had been made in laboratory bloodlines in populations of cattle. Then, in the
animals see review by Wrathall and Sutmoller, 1970s, technological advances provided efficient
1998. However,
after consideration
of epi-
methods for nonsurgical collection, cryopreservation demiologic factors associated with production and
and nonsurgical transfer of pre-implantation bovine transfer of in-vivo-derived bovine embryos, it was
embryos. Thereafter, an alternative with obvious hypothesized that embryo transfer in this species
economic and humane advantages was available for would prevent transmission of disease if appropriate
movement of germ plasm between populations of precautions were taken. Subsequent research on
cattle. specific bovine pathogens within the context of
When embryo transfer became an option, there embryo production technology supported the hypoth-
was understandable concern that the technology esis and provided a foundation for today’s safe-
embryo-handling recommendations. The aim of this paper is to review epidemiologic
Corresponding author. Tel.: 1 1-334-844-2667; fax: 1 1-334-
aspects of bovine embryo transfer and results of
844-4955.
early research that provided the basis for sanitary
E-mail address : strindavetmed.auburn.edu D.A. Stringfel-
low
guidelines found in the Manual of the International
0301-6226 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 3 0 1 - 6 2 2 6 9 9 0 0 1 6 0 - 8
238 D
.A. Stringfellow, M.D. Givens Livestock Production Science 62 2000 237 –251
Embryo Transfer Society. In addition, results of of limiting factors work to prevent the occurrence of
more recent research are summarized with emphasis this complete sequence of events.
on bovine viral diarrhea virus. Finally, we discuss the impact that results of more recent studies and
2.1. Factors limiting exposure of embryos to accumulated experience with commercial embryo
pathogens transfer have had on our current view of strategies
for pathogen-free-embryo production. Under ordinary conditions, numerous factors tend
to restrict exposure of embryos to pathogens. Espe- cially important are, limited mobility of embryos,
2. Epidemiological view of embryo transfer limited distribution of pathogens and precautions
