Abstract
These experiments were carried out to obtain the basic information for in vitro fertilization and development of bovine follicular oocytes matured in vitro. The bovine ovaries were obtained at a slaughter house and the follicular oocytes surrounded by cumulus cells were collected by puncturing follicles with 2-6mm of diameter. Bovine oocytes were matured in vitro for 24-26 hours in a CO2 incubator with 5% CO2 in air at 39$^{\circ}C$. The medium used for maturation was TCM199 supplemented with hormones, pyruvate, FBS and antibiotics. Epididymal spermatozoa were capacitated by in vitro culture for 2-3 hours in BO solution containing bovine serum albumin(5mg/ml) and caffein(2.5mM). Insemination was made by introducing about 10-15 matured oocytes into the suspension of capacitated spermatozoa. Six hour after inseminatin the eggs were transferred to TCM 199 supplemented with FBS(10%) for in vitro development. The results obtained in these experiments were summarized as follows : 1. The maturation rate of oocytes following incubation for 24-26 hours was 78.4%(228/291). 2. Of total 250 oocytes, 172 embryos extruded 2nd polar body following in vitro culture with spermatozoa for 20 hours, and the rates of embryos developed to 2-, 4-, 8-, 16-cells and morula or early blastocyst were 64.0, 39.2, 22.0, 15.2 and 11.2%, respectively. 3. The time needed for development to 2-, 4-. 8-, 16-cell stage and morula was 42.5$\pm$5.4, 58.0$\pm$9.2, 74.4$\pm$11.5, 96.1$\pm$13.4 and 119.0$\pm$18.2 hours, respectively.