The use of stereology method to estimate the volume of feto-maternal exchange area of the bovine placentome during gestation

The functional surface areas of the feto-maternal unit of the bovine placentomes were quantified from Day 100 to 260 of gestation by using stereology. This study was achieved using intact placentomes obtained from an abattoir. There was no change in volume and surface densities of binucleate cells, fetal trophoblast, fetal and maternal tissues, and maternal epithelium with gestation age, although the total volume of these components increased with gestation age from Day 126 to 260. The total surface area of the feto-maternal interface increased in a similar pattern as the placentomal components without a change in the fetal to maternal tissue ratio when estimated with stereology. This is the first study in cattle to quantify and describe the functional surface area of intact placentomes at different stages of gestation and it emphasised the differences between the yak and cattle placentomal development.