Abstract

Eastern giant eland (Taurotragus derbianus gigas) are the largest antelope species in the world and may weigh up to 1000 kg. These unique antelope have bred well in captivity in North America (now numbering approximately 60 individuals in seven institutions), a success that has resulted in a degree of inbreeding. In order to maintain genetic diversity in this population, the introduction of new genes would be beneficial. The risk and cost involved in the importation of new eland into North America makes the importation of cryopreserved semen a more attractive alternative. Semen was collected by electroejaculation from eastern giant eland under anesthesia. Semen and blood (for testosterone levels) were collected at two different times throughout the year to investigate seasonal effects. Testicular firmness was subjectively assessed, and testicular length and width were measured. Testicular volume was calculated from length and width measurements. Sperm morphology, percent (%) motility, progressive motility, and viability were measured on raw semen. Three cryoprotectants (Tris, TEST, and BF5F) were compared for their effects on percent motility, progressive motility, and viability following cryopreservation. Eastern giant eland semen is similar in its characteristics to domestic hoofstock. BF5F was a significantly better cryoprotectant than Tris and TEST. While raw semen quality was similar in fall and spring, thawed semen quality was significantly better from fall BF5F-cryopreserved semen than spring BF5F-cryopreserved semen. Serum testosterone levels were significantly higher in fall than spring. In North America, it is recommended that giant eland semen be collected in the fall for cryopreservation and that BF5F be used as the cryoprotectant.