The macroscopic and Microscopi Functional Anatomy of the Female Reproductive Organs of the Impala (Aepyceros Welampus Lightein, 1812)

The impala is a medium- sized antelope found in eastern and central Africa. It is an intermediate feeding type of ” browsing” species with selective grazing habits but shows little tendency to migrate. A population in the rift valley near lake elmenteita was studied between January 1967 and September 1969, during which period 69 animals were collected. The prenatal and postanal female organs of reproduction were investigated by dissection, histological and histochemical techniques. The placentas was also examined with the electron microscope.Ovulation occurred at random from the left and right ovary although the embryo was always found in the right uterine horn. The development of the ova and follicles was investigated and a biphasic relationship was established. The process of follicular a tresia was studied and evidence put forward suggesting that two waves of follicular destruction occurred at around estrus time.The various stages leading to the establishment and growth of the corpus luteum were studied. The corpora lutea were tested for the presence of hydroxyteroid dehydrogenase. The mean volume of the corpora lutea as well as the mean luteal cell volume showed a rise during early pregnancy and a precipitous fall just prior to parturition. The mean luteal cell volume continued to rise even when there was evidence to show that the cell were no longe producing increasing amounts of progesteronc. Pigment was present in the luteal cells towards the end of pregnancy. The degeneration of the corpus luteum was studied. The investigation of the oviduct revealed that the epithelium undergoes remarkable charges during the sexual cycle and pregnancy. The uterotubal junction was examined.The position attachment and relations of the female reproductive organs were investigated by dissection. Observations were recorded on the extensive uterine enlargement during pregnancy. The prenatal growth of impalas was studied and cube-root weight relationship suggested for a substantial period of fetal development. The establishment and development of the placenta was examined. The relationship between the maternal and fetal tissues was studied with the electron microscope, and an epitheliochorial barrier was found. Observations were made on the vagina and vestibulum vaginae during the prenatal and postnatal stages. Sexual maturity was attained in females shortly after 12 months of age. Although the impalas bred throughout the year, two peaks of calving were detected during February to may and October to December. The observations were discussed and compared to the body of information already available on reproduction in the farm animals.