AbstractsBiology & Animal Science

Although southern white rhinoceroses are the most numerous of the five rhinoceros species in the world, their population is declining and their status is near threatened. Since breeding is an important component in rhinoceros conservation, knowledge about the oestrus cycle should be available. The aim of this study was to get insight in the oestrus cycle of six free ranging southern white rhinoceroses in the Lapalala Wilderness, South Africa by measurement of faecal progestagene metabolites. This study, with duration of 3.5 months, is part of a long term study of IBREAM (Institute for Breeding Rare and Endangered African Mammals), Utrecht University and the University of Pretoria. Faecal samples were collected (from each animal 2-3 times a week) and progestagene measurements were conducted with an Enzyme Immunoassay (EIA). Luteal activity was detected in five out of six monitored rhinoceroses. Four rhinoceroses (Munyani, Mokibelo, Radimpe and Grikie) all showed different hormone profiles. Two animals showed a luteal phase: Munyani showed an oestrus cycle of around 68 days, Mokibelo also showed a luteal phase, but the length was undefined. The other two animals (Radimpe and Grikie) did not show any luteal phase in these 3.5 months. The profiles of the other two animals (Tharo and Mohklaki) were not analysed further due to low sample numbers. A second aspect of this study was to visualize the degradation of progestagene metabolite concentrations in faecal samples over time. Samples for the degradation study were collected at 0, 0.15, 0.30, 1, 2, 4, 8, 16 and 32 hours after defecation from five different rhinoceroses. The study showed no significant effect of time on progestagene concentrations (F(8,32) = 1.48; p = 0.202). It can be concluded from this study that progestagene concentrations are not influenced by degradation in time from 0-32 hours after defecation.