Sperm and testicular measurements and sperm cryopreservation in the giraffe (Giraffa)

Cryopreservation of Giraffe Epidydimal Spermatozoa Using Different Extenders and Cryoprotectants

“…Indeed, of the previous studies which have investigated the cryosurvival of giraffe spermatozoa, these results comprehensively assess the impact of conventional cryopreservation protocols both before and after freezing on a number of sperm parameters. Of the papers that have reported motile spermatozoa post-thaw, our results recorded a 13% increase in motility than previously recorded [ 9 ]. Although there was no effect of treatment on the acrosome integrity of giraffe spermatozoa, the high results reported when pooled across bulls and treatments (84.2 ± 3.17) act as a benchmark for this species for future cryopreservation studies.…”

“…These results signify the importance of glycerol and methylformamide as a cryoprotectant, helping to improve the survival of giraffe spermatozoa. Improved post-thaw motilities offer new opportunities for utilizing ARTs in giraffe species [ 7 , 8 , 9 , 10 , 12 , 22 , 26 , 27 ] and hold promise for preserving the genetics of pure-bred endangered giraffe species or the closely related Okapi.…”

“…To date, data on giraffe sperm cryopreservation are scarce. A total of just five studies have reported the freezing of epididymal or ejaculated sperm using either bovine GENT extenders (Minitube; Tiefenbach, Germany) in combination with dimethylsulfoxide (DMSO) [ 8 ] or TRIS-based egg yolk extenders supplemented with 4–6% glycerol [ 9 , 10 , 11 , 12 ] using either conventional, freeze drying, or ultra-rapid freezing methods. From these five case studies, only two reported motile sperm of <5% and 44% post-thaw ( Table 1 ) [ 8 , 9 ].…”

“…In order to ensure that cryopreserved giraffe sperm might serve simple and advanced applications in ART, it is critical to develop freezing methods that provide both high motility and viability. There are several factors which could contribute to poor sperm quality prior to freezing, including poor animal health prior to euthanasia, time until epididymis retrieval post-mortem, and subsequent collection of spermatozoa or even collection of ejaculate from a stable floor [ 8 , 9 , 10 , 13 ]. However, as seen in other studies, the extender and cryoprotectant used can also have a significant impact on the quality of sperm during the freezing process.…”