Evidence of Expulsion of Unfertilized Ova into the Vagina in Pseudopregnant Rabbits

Abstract

Non-surgical recoveries of unfertilized ova were performed for a month after sterile mating in 22 pseudopregnant rabbits by the vaginal flushing technique. Thirtyone degenerative ova and 13 suspected materials which were analogous to the degenerative ova were recovered in 307 vaginal flushings. More than half of ova (52%) were recovered concentrically on 3 3/4 to 5 days post coitum, and their remains were obtained dispersedly for a long period beyond the termination of pseudopregnancy. The recovery rate of ova, however, was comparatively higher 18 to 22 days post coitum than that of other periods, except for the first 5 days. The earliest ova were detectable in the vaginal flushing 90 hours post coitum and this suggests that the early maternal recognition of the fertilized eggs may be established prior to 90 hours post coitum in pregnant does. The technique of vaginal flushing was also described.