Microvascular architecture of the fetal cotyledons in water buffaloes (Bubalus bubalis) during different stages of pregnancy.

To elucidate the morphological background of physiological differences between bovine and buffalo gestation forty-two placentae ranging from the 3rd to 10th month of pregnancy were used to study the microvascular architecture of the fetal cotyledons in the buffalo. The tissues were prepared for light and scanning electron microscopy by paraformaldehyde fixation and corrosion casting of the fetal cotyledonary vascular system. Histology and vascular casts revealed the buffalo fetal cotyledons to consist of a series of conical villous trees changing from a wide to slender shape during pregnancy, and with a base strictly facing the fetal side.