Post-harvest motility and morphological changes of spermatozoa following caudal epididymal recovery in farmed common eland (Tragelaphus oryx) bulls

Abstract

The caudal epididymal recovery of spermatozoa has been utilised in game animal species to preserve genetically superior material after trophy hunting or slaughter, due to the difficulties of handling wild animals. Furthermore, the potential application of assisted reproductive techniques using harvested spermatozoa may contribute towards maintaining genetic diversity in isolated captive populations internationally. However, this technique requires clear and ideally simple protocols for the collection and handling of gametes after the death of the male animals, as the point of harvest is usually remote in game ranching. Therefore, this research aimed to investigate the effects of time after harvesting sperm under basic field conditions from the caudal epididymides of farmed common eland bulls in terms of their sperm motility and morphological changes. The relationship among these sperm quality parameters was also explored. Six bulls (2–2.5 years old; 203 ± 20 kg) were slaughtered, and their epididymal sperm were harvested and assessed for sperm motility and kinematics at minutes 0, 35, 70, 100, together with sperm viability, sperm head morphometry, and morphology at minutes 0, 20, 40, 60, 80 using CASA. Sperm quality sharply declined after 35 minutes of slaughter, but no effects were seen in sperm head morphometry. This study brings the first information regarding the quality of sperm retrieval from the cauda epididymides and sperm quality under physiological conditions in a uniform age group of eland. Future work should consider the effect of animal age and other individual animal traits, as well as the use of various media and extenders.