Placentation in the Blue Wildebeest (Connochaetes taurinus)

Abstract

IntroductionThe wildebeest is a populous African ungulate, but despite its wide distribution within that continent few reports exist on the structure and endocrine functions of its placenta. MethodsThe pregnant uteri of 43 Blue Wildebeest estimated to be at less than 70 days of the 8 month gestation period were examined grossly and histologically. Results and discussionThe cervix divided into left and right components which eliminated any connection between the uterine horns and limited conceptus development and placentation to the single ipsilateral horn. The placenta was typically ruminant synepitheliochorial macrocotyledonary with numerous flat placentomes developing in the gravid horn. Appreciable quantities of exocrine secretion were accumulated in the lumen of both gravid and non-gravid uterine horns and proliferation of the trophoblast into presumptive villi was evident between the placentomes. The single corpus luteum of pregnancy persisted unchanged during the period of gestation monitored and the mononuclear trophoblast cells of the intercotyledonary, but not the cotyledonary, allantochorion stained strongly for 3-β hydroxysteroid dehydrogenase indicating their likely secretion of progesterone. The binucleate trophoblast cells stained positively with antisera raised against placenta-associated glycoprotein and bovine placental lactogen. Neither the maternal corpus luteum or the allantochorion showed immunohistochemical staining for cytochrome P450 aromatase.