Search

Survival of the five remaining rhinoceros species is threatened. Four of the five species are in managed collections, but captive populations are not self‐sustaining and low reproductive rates make population growth slow.Slow population growth, coupled with behavioural incompatibilities, acyclicity, low genetic diversity, and disease susceptibility, creates the need for assisted reproductive technologies (ARTs) to maintain genetic diversity while bolstering population numbers.Both published and unpublished data are included in this review of ARTs, to facilitate understanding consistencies and variations between and within each rhinoceros species.Progress has been made to address species‐specific characteristics of reproductive physiology in rhinoceroses. This review outlines the ARTs that have been performed and identifies areas in need of research. In vivo technologies have resulted in live calves by artificial insemination, created genetic reservoirs through semen collection, and provided new avenues of gamete retrieval via ovum pickup. In vitro technologies have enabled genetic rescue post mortem and support early stage embryo production through oocyte maturation and fertilisation.As conservation efforts focus on rhinoceroses, improvement of existing techniques and development of new technologies will allow for a broader application of successful rhinoceros ARTs. [ABSTRACT FROM AUTHOR]

Preserving genetic diversity of the critically endangered Addra gazelle ( Nanger dama ruficollis ) could be enhanced through the use of frozen-thawed sperm and artificial insemination. Our aim was to characterize Addra ejaculate traits and to assess the effects of cholesterol-loaded cyclodextrin (CLC) on sperm cryosurvival. Fresh ejaculates were treated with CLC (0, 0.5, 1.5, 3.0, and 6.0 mg/ml) prior to cryopreservation. All males produced spermic ejaculates with >75% sperm motility. The mean ± SEM seminal volume, sperm concentration, percent motility, forward progression, and percent morphologically normal spermatozoa were 3.2 ± 0.3 ml, 1.2 ± 0.3 × 10 9 , 75.82 ± 2.7%, 3.2 ± 0.3 (0–5 scale; 5 = most progressive), and 57.12 ± 3.8%, respectively. More than 92% contained an intact acrosome. There was no effect of time or in vitro incubation on progression or acrosomal integrity on thawed samples ( P > 0.05). Spermatozoa pre-treated with 0.5 mg/ml CLC retained higher ( P < 0.05) motility post-thaw than aliquots treated with 0, 3.0, or 6.0 mg/ml of CLC. Spermatozoa pre-treated with 0.5, 1.5, or 3.0 mg/ml CLC exhibited greater viability than counterparts ( P < 0.05). Sperm kinetics including beat cross frequency (BCF), average path velocity (VAP), curvilinear velocity (VCL), and straight line velocity (VSL) did not differ among samples ( P > 0.05). Linearity (LIN) and straightness (STR) were different among samples after thawing. Results demonstrate treatment with CLC (0.5 mg/ml) protects Addra spermatozoa from cryo-damage. Reported advances will facilitate establishment of a frozen repository and support the genetic management of this critically endangered north African desert antelope. [ABSTRACT FROM AUTHOR]