Embryo transfer in small ruminants: the method of choice for health control in germplasm exchanges

Several thousands of in-vivo-derived sheep and goat embryos, as well as significant numbers from deer, are transferred annually within countries and internationally. The technologies used for superovulation, collection and transfer of such embryos are now well developed, and pregnancy rates of over 60% can be achieved. Such transfers offer a unique opportunity to safeguard the health status of the flocks and herds even when the embryos originate from countries with a radically different health status. Viral diseases which have been investigated with regard to their risks of transfer by in-vivo-derived small ruminant embryos include bluetongue, border disease, pulmonary adenomatosis, maedi /visna and caprine arthritis–encephalitis. Bacterial diseases investigated include brucellosis, campylobacteriosis, mycoplasmosis and chlamydial abortion. Scrapie, a prion disease, has also been studied and will be discussed in another paper. Provided that the sanitary procedures recommended in the IETS Manual (1998) as outlined here, are strictly followed, the risks of transmitting diseases are minimal.  2000 Elsevier Science B.V. All rights reserved.