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8 - Endocrinology of the giant panda and application of hormone technology to species management
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- By Karen J. Steinman, National Zoological Park, Steven L. Monfort, National Zoological Park, Laura McGeehan, Conservation and Research for Endangered Species, David C. Kersey, National Zoological Park, Fernando Gual-sil, Zoológico de Chapultepec, Rebecca J. Snyder, Zoo Atlanta, Pengyan Wang, China Research and Conservation Center for the Giant Panda, Tatsuko Nakao, Adventure World, Nancy M. Czekala, Conservation and Research for Endangered Species
- Edited by David E. Wildt, Smithsonian National Zoological Park, Washington DC, Anju Zhang, Hemin Zhang, Wildlife Conservation and Research Center for Giant Pandas, Donald L. Janssen, Zoological Society of San Diego, Susie Ellis
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- Book:
- Giant Pandas
- Published online:
- 09 August 2009
- Print publication:
- 27 July 2006, pp 198-230
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Summary
INTRODUCTION
Increasing breeding success in the giant panda requires a better understanding of its complex reproductive biology. We know that the female is typically mono-oestrus during a breeding season which occurs from February to May (within and outside China). Behavioural and physiological changes associated with pro-oestrus and oestrus last one to two weeks, during which the female exhibits proceptive behaviours, such as scent marking, to advertise her sexual receptivity (Lindburg et al., 2001). During the peri-ovulatory interval, receptive behaviours (e.g. tail-up lordotic posture) climax with copulation generally occurring over a one- to three-day interval. Birthing occurs from June to October with a gestation of 85 to 185 days (Zhu et al., 2001). This unusually wide gestation span is due to the phenomenon of delayed implantation, a varied interval before the conceptus implants in the uterus and begins foetal development. The driving force behind implantation in this species is unknown. The giant panda also experiences pseudopregnancy, whereby the female exhibits behavioural, physiological and hormonal changes similar to pregnancy.
Behavioural and physiological cues associated with both pregnancy and pseudopregnancy include decreased appetite, nest-building and cradling behaviours, vulvar swelling and colouration, mammary gland enlargement and lethargy. Additionally, temporal and quantitative progesterone patterns (tracked by assessing urinary hormone by-products and progestins) are indistinguishable between pregnancy and pseudopregnancy. Therefore, no definitive test currently exists for identifying pregnant from pseudopregnant giant pandas.
9 - The value and significance of vaginal cytology
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- By Barbara S. Durrant, Conservation and Research for Endangered Species, Mary Ann Olson, Conservation and Research for Endangered Species, Autumn Anderson, Conservation and Research for Endangered Species, Fernando Gual-Sil, Zoológico de Chapultepec, Desheng Li, China Conservation and Research Center for the Giant Panda, Yan Huang, China Conservation and Research Center for the Giant Panda
- Edited by David E. Wildt, Smithsonian National Zoological Park, Washington DC, Anju Zhang, Hemin Zhang, Wildlife Conservation and Research Center for Giant Pandas, Donald L. Janssen, Zoological Society of San Diego, Susie Ellis
-
- Book:
- Giant Pandas
- Published online:
- 09 August 2009
- Print publication:
- 27 July 2006, pp 231-244
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Summary
INTRODUCTION
The giant panda is seasonally monoestrus, experiencing a single oestrus with spontaneous ovulation in the spring (Schaller et al., 1985). Although natural breeding produces the majority of cubs in captivity (Xie & Gipps, 2001), the number of sexually competent breeding males is insufficient to create or maintain a genetically diverse population (Hu, 1990; Xie & Gipps, 2001). Inclusion of males that are behaviourally incapable of mating, but that are genetically valuable, is possible through artificial insemination (AI) (see Chapter 20). Accurate monitoring of the oestrous cycle to pinpoint the time of ovulation is critical for timed matings and, especially, AI success.
The vaginal epithelium of many mammalian species is responsive to changes in circulating oestrogen concentrations. The value of vaginal cytology in monitoring the oestrous cycle of rodents (Zylicz et al., 1967; Parakkal, 1974) and domestic carnivores (Shutte, 1967; Mills et al., 1979) is widely recognised. In routine practice, evaluating vaginal cytology in these taxa involves quantifying proportions of mature exfoliated epithelial cells, also known as superficial, cornified or keratinised cells. Increasing proportions of mature cells are correlated with the pre-oestrual rise in oestrogen as well as oestrous behaviours.
Despite the logistical difficulty of obtaining vaginal cells from most wildlife species, the oestrous cycles of several small carnivores (raccoon dog: Valtonen et al., 1977; river otter: Stenson, 1988; tayra: Poglayen-Neuwall et al., 1989; multiple ferret species: Mead et al., 1990; Williams et al., 1992; mink: Klotchkov et al., 1998; fox: Boue et al.