Abstract
Morulae and blastocysts were recovered from superovulated Holstein heifers 6 or 7 days after their estrus. Embryos were exposed to an equilibration solution containing 10% glycerol and 20% 1, 2-propanediol in PBS +20% new born calf serum at 4°C for 10 min. Embryos were transferred to vitrification solution(VS) containing 25% glycerol and 25% 1, 2-propanediol in PBS at 4°C. Then these embryos were loaded into a 0.25ml plastic straw with VS. The 1M sucrose solution was placed on each side of the VS column which was separated by air bubbles. The straws were plunged immediately into LN gas. Thawing was done in a water bath at 20°C for about 10 sec. The contents of the straws were transferred into a small plastic dish and kept at room temperature for 5 min. The embryos were washed several times in PBS and then examined morphologically before their transfer to recipient heifers by the transcervical method. The transferable embryos following thawing were 14 (70.0%) of 20 morulae and none of 5 blastocysts. Eight (57.1%) of 14 recipient heifers were diagnosed as pregnant by real-time ultrasonography 23 to 33 days and by rectal palpation 53 to 127 days after the transfer.
