After paraffin wax embedding, trophoblast tissues were sectioned to a thickness of 2 m. A total of 10 random sections of trophoblast tissue were taken per ewe. Of these, five were stained with Periodic acid Schiff stain (with haematoxylin as counterstain) for examination of binucleate cells. The remaining five sections were stained with haematoxylin and eosin to
assess epithelial development. Fifteen microscopic images were captured for each stain type by a compound light microscope (Zeiss Axiophot with 40× objective and fitted with DFC 320 camera; Carl Zeiss, Oberkochen, Deutschland, West Germany).