Factors Affecting the Viability of Frozen Stored Cattle Embryos

Abstract

Cattle morulae and blastocysts were frozen, stored in liquid N2 and then warmed and cultured in vitro at 37� 5�C. They were frozen and stored in Dulbecco phosphate buffer enriched with 25 % cattle serum (DB+S)and containing 1�5 M dimethylsulphoxide (DMSO) or 1�0 M glycerol. Embryos were cooled at rates of 0 �13, 0 �15 or O� 30�Cjmin and warmed at rates of 1 �2, 2�2 or 4� 6�C/min (measured over the range 0 to - 50�C). Warming and cooling between 0 and 37� 5�C was at a rate of 0�7�C/min and, after warming, embryos were cultured in DB+S for 12-18 h. A number of embryos were transferred after culture to recipient cows.