1982 Volume 35 Issue 6 Pages 337-340
A total of 64 bovine embryos were frozen in plastic straw (0.25ml). The storage medium used was Dulbecco's PBS with addition. Embryos were held at room temperature for 30minutes and cooled at 1.0°C/min to-4.5°C. The storage medium was seeded at-4.5°C by clasping the outside of each ampoule with forceps which had been precooled in liquid N2. After seeding, the straw was cooled to-35°C at 0.3°C/min, followed by 10 minutes' cooling at 0.1°C/min to-3.6°C, and then plunged directly into liquid N2. Of 55 freeze-thawed embryos, 28 (50.9%) were survived.