For some replicates, some embryos produced using
X-sorted sperm were vitrified. Grade 1 blastocyst and
expanded blastocyst stage embryos were harvested on Day
7 after insemination and washed twice in TCM-199 containing
10% (vol/vol) fetal bovine serum. Harvested
embryos were then vitrified in open-pulled straws as
described [4]. On the day of transfer, vitrified embryos were
thawed as described [4], loaded into 0.25-mL straws and
transported to the farm as described for fresh embryos. Of
the vitrified embryos that were transferred, 25 were blastocysts
and 33 were expanded blastocysts