Just Accepted

This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.

Viability of 24 hours post-mortem recovered bull epididymal spermatozoa diluted with Triladyl® and modified Ham’s F10.

Andrea Raseona , Okello Owiny, Tshimangadzo Nedambale, Daniel Barry

Abstract

Context: The unexpected loss of economically important animals or the inability of the male to mate can result in significant losses in genetic resources, impacting both short-term economic value and long-term population sustainability and resilience. Aim: This study aimed to evaluate viability of bull spermatozoa recovered from epididymides stored at 5 °C for 24 h compared with epididymal spermatozoa collected immediately after bull slaughter, diluted with Triladyl® (EPT) and modified Ham’s F10 (EPH). Ejaculated spermatozoa (EJ) were used as a control. Methods: Cauda epididymal spermatozoa samples were recovered immediately (EPT0 and EPH0) and 24 h post-mortem (EPT24 and EPH24). Spermatozoa samples were separately pooled before dilution with Triladyl® or mHam’s F10 and chilled at 5 °C for 120 h. Key results: Epididymal spermatozoa diluted with Triladyl® showed higher total motility rates (P<0.01) than those diluted with mHam’s F10. The highest spermatozoa motility rates were, however, observed with EJ (P<0.01). Furthermore, EPT0 and EPH0 showed higher spermatozoa motility and kinematic rates (P<0.01) than EPT24 and EPH24, with no significant difference in total motility rates observed between EPH0 and EPT24. The samples EJ and EPT0 displayed no significant decrease in cell viability during the 120 h storage period, maintaining the highest percentages of live cells. Conversely, a significant decline in cell viability was observed after 72 h for the samples EPH0, EPH24, and EPT24, with EPH24 showing the lowest percentage of viable cells. Additionally, <10% acrosome defects were observed across all the samples. Conclusion: The findings from this study demonstrated that refrigeration of epididymides at 5 °C for 24 h effectively maintained spermatozoa viability until 72 h when Triladyl® extender was used. Implications: These results suggest that storing epididymides at 5 °C for 24 hours can be a viable method for preserving bull spermatozoa, which could help mitigate the loss of genetic resources and support both economic and population sustainability. Keywords: Epididymal spermatozoa, Triladyl®, Ham’s F10, Viability, Cooling

AN25157  Accepted 28 June 2025

© CSIRO 2025