[The effect of cumulus oophorus on the fertilization in vitro of mature oocytes of cattle].

The effect of the cumulus oophorus on fertilisation was investigated by 478 in vitro maturated bovine oocytes. Culturing revealed that the amount of defects on the pellucid zone and in ooplasm of cumulus-free oocytes was higher than that in oocytes cultured in the cumulus-oocyte complex (38 percent or 77/203 versus eleven percent or 30/275). Insemination of the cumulus-oocyte complex (COC) seemed to increase the fertilisation capability of bovine oocytes (63 percent or 70/111), though its penetration rate was only 45 percent (111/245) and was thus below that of cumulus-free oocytes (55 percent or 69/126). Use of COC is recommended as basic material for in vitro maturation and fertilisation.