Abstract: 32

POST-COITAL SEMEN COLLECTION AND CRYOPRESERVATION IN THE ENDANGERED SUMATRAN RHINOCEROS (Dicerorhinus sumatrensis).

Terri L. Roth^{2 1}
Center for Research of Endangered Wildlife, Cincinnati Zoo & Botanical Garden, Cincinnati, Ohio ¹
University of Cincinnati College of Medicine, Department of Obstetrics and Gynecology, Cincinnati, Ohio ²

Our goal was to collect and cryopreserve sperm from the only male Sumatran rhinoceros in the United States for future use in artificial insemination (AI) procedures. Two cryoprotectants (glycerol and DMSO; 5%) and two post-thaw sperm processing methods (neat and glass wool column [GW]) were compared. Semen was collected from the vulva of a post-coital female rhino, concentrated, diluted in cryodiluent and frozen (0.5 ml straws) in a dry shipper. Straws (n=2/sample) were thawed (50°C, 10 sec), and aliquots maintained neat or filtered through 0.3 ml GW. Sperm motility index (SMI; 0-100) and morphology were evaluated subjectively, and viability, acrosomal status and capacitation were assessed using fluorescent markers. Semen samples (n=3; 101.7 ± 15.9 ml; 2.5 ± 1.5 × 109 total sperm) exhibited a SMI of 56.7 ± 3.3, and contained 31.3 ± 4.7%, 77.0 ± 3.0%, 90.5 ± 2.5%, and 64.5 ± 9.5% normal, viable, acrosome intact and capacitated sperm, respectively. Glycerol and DMSO proved equally effective (P>0.05) as cryoprotectants, and regardless of processing method, post-thaw samples retained >70% of all pre-freeze characteristic values. GW SMI at 0 h (60.9 ± 2.8) and 6 h (42.3 ± 2.1) were higher (P<0.05) than those for neat samples (41.6 ± 1.2 and 29.2 ± 1.2, respectively), but both decreased (P<0.05) over 6 h. GW samples contained more (P<0.05) viable (74.8 ± 3.5%) and acrosome intact (86.7 ± 1.4%) sperm than neat samples (64.3 ± 2.4% and 76.8 ± 2.5%, respectively), but had no effect (P>0.05) on numbers of normal (29.9 ± 2.5%) or capacitated (66.8 ± 4.1%) sperm. Overall, GW processing yielded higher quality samples but only half the number of motile sperm. In summary, Sumatran rhino semen of moderate quality can be collected from post-copulatory females. Samples cryopreserved in glycerol or DMSO exhibit only slight reductions in quality and have potential for use in AI. (Funded by the International Rhino Foundation and CREW's Carl & Edyth Lindner Postdoctoral Fellowship)

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.