Abstract

The purpose of this work is to present preliminary results of succesfull vitrificaction of bovine embryos produced in vitro using the Open Pulled Straw (OPS) method. Open Pulled Straws were made by pulling 0.25 ml French mini straws which were heat-softened until their inner and outer diameter were reduced to half of their original dimensions. Ninetythree blastocyst were selected and deposited individually in vitrification solutions 1 and 2 containing TCM199 (20% BFS), ethylene glycol and dimethyl - sulfoxide (DMSO), for 1 minute and 20 seconds respectively. During the last period a drop of 2 ?1 containing the embryo pulled into the straw by capillarity effect. Inmediately after that all straws were deposited into liquid Nitrogen. Eighty three blastocysts were recovered after thawing. Fifthy four percent of these were re- expanded or hatched after 24 hours of in vitro culture. After 72 hours of in vitro culture 29% of the blastocysts matured. Even though our results are slightly lower to those reported in the literature, they show that it is possible to successfully vitrify bovine blastocysts produced in vitro using the OPS method.