The purpose of this study was to establish an efficient combination of assisted hatching and cryopreservation procedures for producing @entity291 embryos in vitro. A total of 1312 day 7 blastocysts were subjected randomly to 14 different combinations of three factors: osmotic stress, assisted hatching and vitrification. Re-expansion, initiation and completion of the hatching process, as well as attachment to the culture dish, were analysed by SAS Genmod procedure. Incubation with @entity969 was found to decrease survival rates; among the assisted hatching procedures used, zona fenestration resulted in higher survival rates compared with partial zona dissection and controls; and vitrification decreased survival and further development. The combined effect of @entity969 incubation and vitrification decreased further development markedly, as did partial zona dissection followed by vitrification. Partial zona dissection performed in medium containing @entity969 severely lowered embryo survival. Zona fenestration without @entity969 incubation followed by vitrification did not compromise further embryo development: 86%, 84% and 79% of the blastocysts initiated, completed hatching and attached to the bottom, respectively. These data were not different from the controls (80%, 76% and 63%, respectively; P > 0.05). Cell count analysis revealed a decrease in the total number of cells as a result of the assisted hatching and vitrification compared with controls (135 versus 202, respectively; P < 0.0001). Although embryo transfer results (36% pregnancy rate and 30% calving rate) require further improvement, this combination of methods may prove useful in the commercial production of @entity291 embryos in vitro.

Survival and development of XXXX blastocysts produced in vitro after assisted hatching, vitrification and in-straw direct rehydration.

@entity969 :: ('MESH:D013395', 'Chemical') :: ['sucrose'] @entity291 :: ('9913', 'Species') :: ['bovine']
@entity291 :: (9913,Species) :: ['bovine']
