Monitoring the oestrous cycle of free roaming African elephants (Loxodonta africana africana) using an Enzyme Immunoassay for Progesterone

Abstract

Management and conservation of African elephants in the fenced reserves of southern Africa is essential because elephant overpopulation is now uniformly accepted as a serious threat to biodiversity. Immunnocontraceptive vaccines have been proposed as an alternative to culling for population management and are currently being used in several small private parks for this purpose. Information on the reproductive endocrine status of treated animals is of considerable additional value for evaluating the effectiveness of such fertility control measures and to help in the development of more effective treatments or administrations protocols. In this respect, analysis of faecal progesterone metabolites is, primarly because of the non-invasive nature of sample collection, a valuable tool for monitoring the reproductive state and cyclicity of both treated and non-treated animals to determine how and for how long the effects of particular treatments influence fertility. The Progesterone Enzyme Immunoassay (PEIA) has previously been validated for determining 5α pregnane-3-ol-20-one concentrations in the faeces of African elephants. Gestagen concentrations were measured using an antibody raised against the progesterone metabolite 5-pregnan-3-ol-20-one. Further studies are required to assess how rapidly the progestagens are degraded in faeces, how concentrations are affected to time of year or climatic conditions (Fieβ et al reported significant differences between the dry and wet seasons), and whether it is possible to assign cut-off values for luteal activity that are generally applicable, or whether monitoring will be limited to assessing patterns on the basis of serial sampling.