A secure health status associated with the production and trade of in vitro derived cattle embryos

The number of in vitro produced embryos used worldwide is increasing. In so me countries such as Canada and the Netherlands, genetics improvement progr ams use in vitro produced embryos extensively. Controlling the sanitary ris ks associated with the production of these embryos relies on a different se t of guidelines compared with the use of in vivo produced embryos. There ar e particular risk factors: (1) the health status of the semen used for in, vitro fertilization, (2) the health status of the oocytes of the donor cow; (3) the freedom from contamination of the media and reagents used, and (4) the environmental conditions associated with oocyte maturation, in vitro f ertilization, cultivation and embryo transfer. Some of these risks have alr eady been studied, especially the principal pathogens found in bull semen ( Brucella sp., Haemophilus somnus, Campylobacter fetus, Leptospira sp. etc.) . The oocytes may also be contaminated, either intracellularly (Campylobact er fetus) or more frequently when virus (BHV-1, BVDV) or bacteria (Leptospi ra hardjo), Campylobacter fetus) located in the ovarian follicle, are adsor bed onto the zona pellucida. Granulosa or cumulus cells, or even oviductal cells, can be a source of infection when contaminated with virus (BHV-1, BV DV). For the production of in vitro embryos that present no health risk, on e must rely on using closely controlled and monitored cell lines, media and reagents that are guaranteed free of products of animal origin. (C) 2000 E lsevier Science B.V. All rights reserved.