Collection of tubal stage bovine embryos by means of endoscopy - A technique report

Here we describe the development and optimization of endoscopy-mediated tra nsvaginal access for collecting ova and embryos from the bovine oviduct. Th e novel technique was developed in three experimental setups: In Experiment 1 embryos were collected unilaterally from nonstimulated heifers. We flush ed the oviducts of superovulated heifers unilaterally (Experiment 2) and bi laterally (Experiment 3). In Experiment 1 the oviducts of 18 heifers were s uccessfully cannulated, which resulted in the collection of twelve 1-cell t o 8-cell embryos and one empty zona. Unilateral flushing of 13 animals (Exp eriment 2) resulted in 84 ova with 6.3 +/- 3.2 observed ovulation sites. Bi lateral flushing of 25 animals (Experiment 3) resulted in 293 ova plus 10 e mpty zonae from 11.8 +/- 5.4 ovulation sites. Given our experience from the se studies we optimized the technical equipment by improving the flushing m etal catheter (Experiment 4). The novel catheter hermetically sealed the lu men of the ampulla at the moment, the medium was flushed through the oviduc t. This resulted in a visible flow of medium via oviducts toward the embryo filter connected to an embryo flushing catheter that was fixed in the uter ine hems. Our endoscopy-guided method is minimally invasive and facilitates the flushing of tubal stage embryos. (C) 2001 by Elsevier Science Inc.