(bOn Day 19 of gestation pregnant recipient dams (n = 10 per group) were euthanised via captive bolt and exsanguination. The uterus was immediately removed and placed on ice. After removal of excess connective tissue and separation of the uterine horns at the internal os of the cervix, each horn was flushed (0.9% saline: 50 ml per horn) for recovery of the embryo. The embryo was dissected free from the extraembryonic membranes and preserved in a 5 ml vial filled with 10% buffered formol saline. The extraembryonic tissues were placed in histology cassettes and preserved in 10% buffered formol saline.