Low temperature preservation of cattle blastocysts

Abstract

Thirty six early to fully expanded blastocysts were frozen in 1.5 m DMSO/PBS solution and stored from 25 to 268 days in liquid nitrogen. After thawing 35 embryos were recovered and 28 (80%) were judged normal. Seventeen embryos were transferred surgically to 16 recipients and 7 (43.8%) became pregnant. The first calving is expected in February and the rest in April 1978. All pregnancies have recently been reconfirmed by rectal palpation and there has so far not been abortion or resorption of fetuses.