Influence of the Time between Removal and Cooling of the Canine Epididymis on Post-Thaw Caudal Epididymal Sperm Quality

Abstract

ABSTRACT. The effects of the time period between canine epididymis removal and cooling on post-thaw caudal epididymal sperm quality were investigated. Sperm recovered from the epididymis stored for 6 hr at 4 or 20C exhibited similar motility. However, when the epididymis was stored for 12 hr or longer at 20C, sperm motility was significantly lower than that at 4C (p<0.01). The post-thawed qualities of sperm recovered from the caudal epididymides that had been stored at 20C for 0 or 6 hr and then at 4C for 24 hr after removal were not significantly different. Therefore, leaving the canine epididymis at 20C for up to 6 hr after its removal may have little effect on the post-thaw quality of recovered caudal epididymal sperm.KEY WORDS: canine, caudal epididymal sperm, frozen semen.J. Vet. Med. Sci. 71(6): 811-815, 2009 Many wild animals including canids are endangered. As artificial reproductive techniques to preserve these species, methods of gamete preservation have been investigated [1,5,7]. Gametes from male animals are generally collected by ejaculation. However, when animals die accidentally, sperm are recovered from the cauda epididymis, the sperm storage site [3,4,8].In a previous study [3], unilateral intrauterine insemination with sperm that was recovered from canine caudal epididymis in prostatic fluid (PF) and cryopreserved resulted in a high conception rate, 80.0%. We also showed that when caudal epididymal sperm were recovered after storage of the epididymis in sterile physiological saline at 4C for 48 hr, sperm motility was reduced, but intrauterine insemination with this post-thaw sperm again led to a high conception rate, 80.0% [4]. In these two experiments, the epididymis was kept at 4C immediately after removal, and the time period until the start of cooling after removal was not considered. However, when the bodies of male animals, such as wild animals, that have died accidentally are discovered, it is likely that several time have already passed under various temperature conditions, and so the epididymis can rarely be cooled immediately. This suggests that the time until cooling needs to be investigated.It has been reported that mouse caudal epididymal sperm shows a sperm motility of approximately 30% after 10 days of postmortem storage at 4C [6], but only shows a sperm motility of 10-15% after 24 hr of storage at room temperature [12]. Hishinuma et al. [2] reported that when the sika deer (Cervus nippon) epididymis is removed 4 hr postmortem and stored at 4C for 1-4 days, the caudal epididymal sperm motility is high, at approximately 50%, but, when removed 8-12 hr postmortem and stored at 4C for 1-4 days, the sperm motility is as low as 6.4%. These reports suggest that, in order to recover highly motile caudal epididymal sperm, it is important to store dead male animals immediately after death at 4C or to remove the epididymis as soon as possible and rapidly store it at 4C, thereby reducing the time of exposure to room temperature. However, in all the reported studies concerning...

Role of prostatic fluid in cooled canine epididymal sperm

“…Furthermore, the PF collected from the specific male dog did not worsen or improve the results in this study, likewise previously reported (Hori et al., ; Hori, Hagiuda, Endo, et al., ; Hori, Hagiuda, Kawakami, et al. ; Hori et al., ; Hori et al., ), and the difference between the PF used was not seen. Therefore, it seemed that there was not the influence with the different canine PF.…”

DNA integrity of fresh and frozen canine epididymal spermatozoa

“…the birth of offspring with a low conception rate [1][2][3]. The effects of cryopreservation on motility, as well as membrane and acrosomal integrity of canine epididymal spermatozoa have been previously investigated [4][5][6], but no information is available on its potential effect on DNA integrity. Sperm DNA integrity has been evaluated in fresh ejaculated [7][8][9][10] and epididymal canine semen [11].…”

Effect of semen collection by transrectal massage of accessory sexual glands or artificial vagina on the outcome of breeding soundness examinations of Italian yearling beef bulls

“…These authors suggested that this higher value might have been due to the cold shock caused by the crushed ice that was used to transport the epididymis. However, for dog [22], stallion [23], and ram semen [24], it has been reported that the preservation of the epididymis at 4 C does not significantly alter the morphologic features of the spermatozoa it contains. A higher percentages of proximal droplets in spermatozoa collected via EE compared with samples collected via TRM from 18-month-old Angus bulls have also been reported [12].…”