tThe effects of different denuding procedures used during the in vitro culture of porcineembryos on oocyte damage and aspects of porcine embryo development were investigatedin a series of studies. Oocytes were denuded by vortexing or pipetting after 44 h in vitro mat-uration (IVM) or pre-denuded after 22 h IVM. The total oocyte death rate was significantly(P < 0.05) higher for pre-denuded (27.3 ± 1.4%) than for vortexed (20.3 ± 1.2%) or pipetted(16.2 ± 2.2%) oocytes. There was no significant difference between the treatments in thepercentage of oocytes that extruded the first polar body. The type I cortical granule distri-bution (reflecting complete maturity) and normal spindle formation rates were significantlylower in the pre-denuding than in the vortexing and pipetting treatments. Blastocyst forma-tion rates were significantly lower for the pre-denuding treatment in PA (25.7 ± 4.5%) andIVF (6.1 ± 1.5%) culture than in the vortexing (PA 42.0 ± 4.5%; IVF 11.2 ± 0.5%) and pipetting(PA 43.4 ± 3.1%; IVF 9.4 ± 1.6%) treatments. The proportion of oocytes developing to blas-tocysts in SCNT culture was not significantly different between treatments ranging from9.9 ± 1.8% for pre-denuding to 12.3 ± 2.7% for vortexing. No significant differences in apo-ptosis or embryonic fragmentation were observed. This study shows that the denudingprocedure used for porcine oocytes during the in vitro production of embryos can signif-icantly affect oocyte damage, spindle patterns, oocyte maturation, embryo developmentbut not embryonic apoptosis or the frequency of fragmentation