The Microscopic And Microscopic Functional Of The Impala (aepyceros Melampus Lightensein 1912)

Abstract

The impala is a medium-sized antelope found in Eastern and Central Africa. It is an intermediate. feeding type of "browsing" species with selective grazin habits but shows little tendency to migrate. A population in the Riit Valley near Lake Elmenteita was studied between January 1967 and September 1969, during which period 69 animals were collected. The prenatal and postnatal female organs of reproduction were investigated by dissection, histological and histochemical techniques. The placenta 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 follicle was investigated and a bipha0ic relationship was established. The process 0f follicular atresia was studied and evidence put forward suggesting two waves of of follicular destruction occured at around estrus time. The various sstages legding to the establishment and growth of the corpus luteum were studied. The corpora lutea were tested for ~he presence of

hydrosteroid dehydrogenase. The mean volume of the hydroxysteroid dehydrogenase . The mean volume of the corpora luten as well as luteal cell showed a rise during early pregnancy and precipitous fall just prior to parturition. The mean luteal cell volune continued to rise even when there was evidence to sh0w that the cells were

no longer producing increasing amounts of progesterone. Pigment was Present in the luteal cells towards the end of pregnancy. The degeneration of the coruus luteum was studied. The investigation of the oviduct revealed that the epithelium undergoes remarkable changes during the sexual cycle and pregnancy. The uterotubal junction was examined. The position, attachment and relations of two 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 a 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 euitheliochorial 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 calvine were detected during February to May and October to December , The observation were di sc.u.s.sed and compared to the body of information already available on reproduction in the farm animals.