Received August 11, 2001
Accepted March 12, 2001

The purpose of these experiments was to test the appropriateness of modified SOF, supplemented with glucose to support bovine in vitro derived embryos to develop and reach the blastocyst stage. Ovaries were collected from cows after slaughter and storage at 28°C in NaCI 0.9% solution for transport to the laboratory. An average 20 COCs were placed in 1OOµL drops covered with mineral oil and were cultured for 24 hours at 39°C and 5%CO2 in air. Frozen-thawed spermatozoa were separated by discontinuous Percoll gradient in Sperm-TALP for in vitro fertilization. Capacitation was induced by incubating the spermatozoa in Fert-TALP supplemented with 5.76µg/mL heparin, 1,1µg/mL hypotaurine, 0.183µg/mL epinephrine, 3mg/mL penicillamine for 30 minutes at 39°C and 5% CO2 in air. A total of 106 spermatozoa/mL were added to 100µL droplets of Fert-TALP covered with mineral oil and containing 20 COCs. After 18 hours of culture the oocytes/zygotes were pooled and randomly divided into the experimental groups. The 1 .5mM glucose was added to the modified SOF medium in three different moments: Group I:20 hours after FIV; Group 2:48 hours after FIV and Group3:72hours after FIV. The culture was performed by exposing the embryos to 5%CO2, 7%O2 and 88%N2, at 39°C in one incubator chamber. Experiments were repeated 3 or 4 times for each treatment. The cleavage rates in the first experiment were 67.8%(97/143) in the group 1 and 69.9% (116/166) in the group 2. ln the groups 1 12.6% (18/143) achieved the blastocyst stage on Day 7, 8.4%(12/143) on Day 8