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Abstracts / Presentations

Dedicated to providing cost efficient and accurate diagnostic animal specimen testing for Zoos, Wildlife/Conservation Organizations and Universities.

         Managed by specialists in Comparative Endocrinology, our laboratory utilizes enzyme immunoassay (EIA) techniques to help clients gain a greater understanding of exotic and domestic animal Reproduction, Stress (Animal Welfare), Immunology, Growth and Metabolism, Homeostasis and Life History Transitions. We have extensive experience with methodologies for extraction/concentration of analytes from a variety of biological matrices and the procedural skills and knowledge necessary to validate novel endocrine applications. 

Enzyme Immunoassays (EIA)
        Progesterone (P4)
        Estrogen (E2)
        Testosterone
        Progesterone Metabolites (PdG)
        Estrogen Conjugates (E1C)
        Corticosterone
        Cortisol
        Numerous other assays - available upon request      

Fees and Submission Form

Dr. Monica Stoops
Director of Reproductive Sciences

Dr. Jessye Wojtusik
Lead Scientist

Stacey Meeker
Biomaterial and Reproductive Lab Coordinator

Jonathan T. Aaltonen
Scientific Services Operation Specialist

Leon Krause
Endocrine Lab Technician

Assisted Reproductive Technology (ART)

Assisted Reproductive Technology (ART) refers to a range of techniques used to help animals reproduce when natural breeding is not possible or practical. These methods, including sperm collection, hormone monitoring, artificial insemination, cryopreservation, and genetic management (such as sex-sorting), are crucial in wildlife conservation. ART can help to address reproductive challenges, enhance genetic diversity, and support the survival of endangered species. At OHDZA, the reproductive science team is committed to developing and optimizing ARTs that are practical and effective in real-world settings, always prioritizing animal welfare and safety.

Artificial Insemination (AI) 

Artificial insemination (AI) is a vital tool in overcoming reproductive barriers, such as logistical, behavioral, and health-related issues, that can hinder natural breeding. By directly introducing sperm into the female reproductive tract, AI enhances breeding success, especially for species where natural mating is impractical or dangerous. 

Advancements like sex-sorting can improve AI’s effectiveness by enabling the selection of male or female offspring, enhancing genetic management and supporting balanced populations. However, further research and development are needed to make these technologies more accessible and viable for wildlife conservation.

Cryopreservation and Biobanking

Cryopreservation is the process of freezing biological materials at ultra-low temperatures to preserve their viability for future use. This includes gametes, embryos, and even entire genomes. Our Reproductive Sciences Department maintains a genome resource bank (GRB) with over 20,000 samples from more than 50 species, some preserved for over 30 years.

This approach serves as an insurance policy against population loss due to threats like habitat destruction, disease, or genetic bottlenecks. Cryopreserved samples can be transported globally for breeding programs, minimizing the need to move live animals, and ensuring the long-term preservation of genetic diversity in both wild and managed populations. This technology also helps protect valuable genetic material from aging, non-reproductive, or deceased individuals, enhancing conservation efforts and long-term species recovery planning.

Gamete Rescue

Gamete rescue involves the collection of sperm, eggs, or tissue from deceased individuals, providing valuable genetic resources that might otherwise be lost. These collections contribute to our biobanking efforts by preserving gametes, tissue samples, and DNA for future research or breeding programs. This practice ensures that even after an animal’s passing, their genetic contribution can still be utilized to support conservation and genetic diversity, aiding in the restoration of threatened species and minimizing the loss of irreplaceable genetic material.

Hormone Monitoring

Non-Invasive Diagnosis of Pregnancy and Reproductive Disorders in a Variety of Species by Measuring Fecal Reproductive Hormone Metabolites

To diagnose pregnancy or determine if there is a reproductive disorder in a non-domesticated animal, multiple samples are required over an extended time period.  For that reason, blood sampling is not an option because this would require chemical immobilization, unless the animal has been trained to allow voluntary blood sampling.  Techniques have been developed to measure the metabolites of reproductive hormones in urine or feces, and this has proved to be an invaluable procedure to:

• Determine seasonality for male/female introductions
• Diagnose pregnancy and forecast parturition
• Evaluate the effectiveness of assisted reproduction protocols such as exogenous hormone delivery and artificial inseminations
• Evaluate fertility/infertility of individual animals.  These procedures assist in improving reproductive success and the well-being of animals in managed breeding programs.

Philippine Crocodiles

Of the 24 species of crocodilians alive today, over half are threatened with extinction. Omaha’s Henry Doorly Zoo and Aquarium is home to six species of crocodilians (American alligator, American crocodile, Johnson’s crocodile, Philippine crocodile, Smooth fronted caiman, and Spectacled caiman) that are housed within the Lied Jungle and Desert Dome/Kingdoms of the Night exhibits. The Philippine crocodile is the most threatened crocodilian worldwide, estimated at less than 150 of them inhabiting fragmented habitat across three Philippine islands.

Compared to mammalian species, the development and application of Assisted Reproductive Technologies (ART) in reptilian species has been limited. For most crocodilian species information is lacking regarding basic reproductive physiology and endocrinology. Reptilian reproductive cycles are controlled by many factors including daylength, temperature, humidity, and nutrition. Establishing the external and internal factors that trigger seasonal breeding in reptiles can be a challenge in managed care.

Our Animal Care and Reproductive Sciences teams have been working to help expand the understanding of crocodilian reproductive biology. Husbandry and management changes are made based on knowledge of the species' natural biology to optimize reproduction. Through continued training, our male Philippine crocodile ‘Phil’ participates in voluntary semen collections, and our females participate in regular ultrasound exams to monitor follicle growth. This work is foundational toward our goal of developing ARTs like artificial insemination (AI) for crocodilians. Every contribution to their reproduction and propagation is a step towards preserving the species.

Enhancing the Reproductive Health and Well-Being of African Elephants

Omaha’s Henry Doorly Zoo and Aquarium is dedicated to pioneering innovative strategies that prioritize animal care and well-being. Central to our approach is ensuring that our elephants maintain their autonomy and comfort, which is key to their overall happiness. Our "Herd First" approach to elephant management reflects the natural social dynamics found in the wild. As the largest land mammals on Earth, elephants form deep, lifelong bonds and navigate complex social structures that evolve over time. By emulating these natural behaviors, we foster a supportive environment that values social interactions and a matriarchal herd structure, which enhances the collective well-being of the elephants.

Our Herd First strategy has proven to be successful, leading to the birth of five healthy elephant calves in recent years. Our thriving herd of African elephants demonstrates the significant strides we are making in creating sustainable populations of these incredible animals. This success is a direct result of collaborative efforts among various departments, other zoos, and in situ conservation partners.

Respecting the elephants' autonomy is a core value in our management approach, especially during the monitoring process. Allowing them to choose when and what samples are collected is crucial for maintaining their well-being. In close partnership with our Animal Health and Care teams, the Reproductive Sciences department analyzes reproductive and adrenal hormone concentrations in biological samples from our elephants. These vital analyses provide us with essential information about their reproductive health, which informs management decisions. Additionally, by collecting behavioral and physiological data, we are working to develop new well-being metrics for elephants in managed care.

Polar Bears (Ursus maritimus)

Polar bears are threatened with extinction due to loss of sea and associated impacts including limited reproductive success. Populations in human care are important for ensuring the polar bear species continues to survive, but they are not sustainable, the number of cubs born each year are not replacing the adults lost due to old age, and only ~10% of pairs are producing cubs.

Polar bears do not currently reside at OHDZA; however, blood samples collected from Bam Bam, the beloved female polar bear who was born here and left to retire in 2018, are helping scientists to learn more about reproductive biology in polar bears and develop new strategies to conserve this threatened species.

Reproductive biology of polar bears is not well understood and therefore it is difficult to determine what is causing the bears to be less fertile. Our reproductive sciences team is working with collaborators at other zoos to define reproductive hormone patterns in polar bear blood so we can better our understanding of how fertility is impacted by environmental factors and what can be done to improve number of cubs produced.  

Our Reproductive Sciences team is working to transform how rhino populations are managed for genetic and demographic viability within our Nation's zoos. Boasting leading experts in the field of rhinoceros reproduction, our scientists have been on the forefront of developing and optimizing Assisted Reproductive Technologies (ART) for rhinos. Strong collaborative ties among zoos and conservation facilities enhance our ability to provide individualized training and/or support for natural and assisted rhino breeding efforts.

Sunflower Sea Stars (Pycnopodia helianthoides)

Sunflower sea stars are generalist predators that help to control sea urchin populations, preventing urchins from devastating kelp forests and therefore, play a critical role in maintaining the ecological balance of these habitats. They were once abundant and widespread along the west coast of North America, from Alaska to Mexico, but between 2013 to 2018 over 90% of their global population were wiped out due to sea star wasting disease. 

Our Animal Care and Reproductive Sciences teams are working together along with multiple collaborators at facilities across the US to expand our knowledge of Sunflower sea star biology and to support recovery and conservation efforts. OHDZA  aquarium staff are working to develop and improve aquaculture techniques to support the growth and development of offspring for stabilizing the population and reintroduction efforts. Reproductive Sciences is focused on cryopreservation for gametes and larvae to preserve genetic diversity of the population in human care.

Staff Publications (pre-2022)

Manuscripts