Sperm motility, kinematics, morphometry and morphology over two seasons in free-ranging African elephants (Loxodonta africana)

Ilse Luther, Liana Maree, Antoinette Kotze, Thomas Hildebrandt, Frank Göritz, Robert Hermes, Gerhard van der Horst

Department of Medical Bioscience, University of the Western Cape, Private Bag X17, Bellville, 7535, South Africa; National Zoological Garden, South African National Biodiversity Institute, PO Box 754, Pretoria, 0001, South Africa; GEOsperm, Wildlife Reproduction and Biotechnology, PO Box 3300, Brits, 0250, South Africa; Department of Genetics, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa; Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, Alfred-Kowalke-Straße 17, 10315, Berlin, Germany

Abstract: This study aimed to address the lack of information on quantitative semen and sperm characteristics of free-ranging African elephants. Nineteen ejaculates were collected from 12 elephant bulls by means of electroejaculation in spring (Season 1, end of dry season, n=7) and in autumn (Season 2, end of rainy season, n=12). While most elephant cows are in oestrus in the rainy season, it is not evident whether sperm quality also improves during this period. Semen samples were assessed using computer-aided sperm analysis (CASA), brightfield microscopy and transmission electron microscopy. Seasonal differences and individual variation in sperm quality of bulls were apparent, with ejaculates collected during Season 2 revealing higher percentages for total motility, progressive motility, rapid-swimming spermatozoa and kinematic parameters compared with Season 1 (P<0.05). Although normal sperm morphology percentage was similar over the two seasons, more sperm tail defects were found in Season 2 (P<0.05). The baseline reference data and multivariate sperm parameter associations reported in this study can be used to predict elephant bull sperm quality and potential to fertilise. It is clear that CASA can detect subtle differences in sperm quality of African elephant ejaculates and should be the approach for future investigations.

Reproduction, Fertility and Development – https://doi.org/10.1071/RD19182
Received 21 September 2018, accepted 25 July 2019, published online 24 January 2020