Embryo transfer as a method for eliminating pathogenic agents in a rabbit colony

To regain the SPF status of a contaminated but genetically valuable rabbit breeding unit, embryos from the contaminated does were transferred into SPF recipient females. Embryos were collected on day 3 of gestation by flushing uterine horns. All usable embryos were frozen, and a portion of them were preserved in liquid nitrogen to form a stock of highly valuable genotypes. Thirty-two stimulated does produced 893 embryos, 821 (92%) of which had an intact zona pellucida and were cryopreserved. Of this stock, 478 embryos were thawed, 466 were recovered (97.5%) and 417 were of good quality (87.2%). In 30 does, 10 to 18 embryos were surgically transferred per recipient doe and 24.9% (104/417) of them developed to term after transfer. This corresponds to an average number of 3.47 (104/30) live newborns per recipient. Health screenings performed on sanitized rabbits confirmed the disappearance of pathogenic agents.