ASSESSMENT OF MALE GIANT PANDA SEASONAL REPRODUCTION, SEXUAL MATURITY AND COMPARATIVE SPERM CRYOTOLERANCE

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dc.contributor.advisorOttinger, Mary Annen_US
dc.contributor.advisorHoward, JoGayleen_US
dc.contributor.authorAitken-Palmer, Copperen_US
dc.contributor.departmentAnimal Sciencesen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2011-02-19T07:10:41Z
dc.date.available2011-02-19T07:10:41Z
dc.date.issued2010en_US
dc.description.abstractThe giant panda is unique as one of the most studied endangered species. Interestingly, despite this, little is known about basic male reproductive physiology. Behavioral problems have posed challenges for reproductive success in the captive population, while geographical isolation and habitat fragmentation threaten the wild population. Techniques such as sperm cryopreservation can improve genetic management and reproductive success within captive populations. But without comparative freeze-thawing studies, diverse methods used for cryopreservation result in inconsistent post-thaw quality, potentially compromising sperm quality and fertility for artificial insemination. This, compounded by limited knowledge of male reproductive physiology, has challenged conservation goals for the giant panda. Specific objectives of this study include: 1) assess the influence of season on male giant panda reproduction by determining annual changes in testis size, body size, testosterone production, sperm quality and production, and reproductive behaviors throughout the year; 2) characterize the onset of sexual maturity in the male giant panda by documenting the timing of initial sperm production, increasing testicular size and body weight, rising androgen production and initiation of reproductive behaviors; and 3) identify factors influencing giant panda sperm cryopreservation by comparing the effect of freeze-thawing on sperm motility, acrosomal integrity, forward progressive movement and longevity. Results provide evidence that 1) reproductive seasonality in the male giant panda is more protracted than the female, with coordinated increases in testes size, androgen production, sperm density, and sexual behaviors; thereby maintaining reproductive competence to prepare for, and accommodate, a brief unpredictable female estrus; 2) sexual maturity in the male giant panda is first observed with consistent sperm production at 5.5 yr, then accompanied by increasing body weight, fecal androgen concentrations, and culminating with the onset of reproductive behaviors, such as scent marking between 7.5 - 8.5 yr; and 3) the giant panda spermatozoon has the capacity to withstand cold stress applied by multiple means, specifically after freezing and thawing using a unique field friendly dry shipper approach. These data greatly improve our understanding of male giant panda reproductive physiology, specifically seasonal rhythms, the cascade of changes associated with sexual maturation, and insights into improved comparative approaches for sperm cryopreservation.en_US
dc.identifier.urihttp://hdl.handle.net/1903/11247
dc.subject.pqcontrolledAnimal Sciencesen_US
dc.subject.pqcontrolledZoologyen_US
dc.subject.pqcontrolledWildlife Conservationen_US
dc.subject.pquncontrolledChinaen_US
dc.subject.pquncontrolledGiant pandaen_US
dc.subject.pquncontrolledpubertyen_US
dc.subject.pquncontrolledreproductionen_US
dc.subject.pquncontrolledseasonal reproductionen_US
dc.subject.pquncontrolledsperm cryopreservationen_US
dc.titleASSESSMENT OF MALE GIANT PANDA SEASONAL REPRODUCTION, SEXUAL MATURITY AND COMPARATIVE SPERM CRYOTOLERANCEen_US
dc.typeDissertationen_US

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