The Sustainability Crisis in Zoos Needs Both Archival and Prospective Studies: The Reproductive Health Surveillance Program Has Both
American Association of Zoo Veterinarians Conference 2019
Dalen W. Agnew1,2, DVM, PhD, DACVP; Anneke Moresco, DVM, PhD1,3
1Reproductive Health Surveillance Program, 2Michigan State University, East Lansing, MI, USA; 3Denver Zoo, Denver, CO, USA


The Reproductive Health Surveillance Program (RHSP) has been archiving reproductive tissues from a large variety of species, ages, and contraceptive treatments since 1995 and currently holds over 3,000 cases.3 This archive allows for valuable retrospective research that has identified important trends in reproductive disease such as the long-term carcinogenic effects of MGA in felids,5 or more recently, that female suids develop a range of endometrial lesions ranging from hyperplasia to malignant cancers, but that there was no correlation of uterine lesions and contraceptive use,2 or that zebras do not develop significant ovarian or endometrial lesions after administration of PZP. Although very valuable, archived samples will never have the consistency in collection methods that a prospective study can have. When the RMC is contacted about clinical cases, the RHSP actively participates in advising, using the information gained through the archive. Therefore, the RHSP also currently supports more prospective studies. A few examples include:

1.  We are evaluating the genetic factors for the remarkable propensity of African painted dogs (Lycaon pictus) to develop adenomyosis and pyometra.

2.  Carnivores (felids in particular) seem to have long reversibility intervals after treatment with deslorelin;4 however, it is unknown if this latency period is due to very low levels of deslorelin release from the implant or due to a strong suppression of the pituitary receptors. A new assay is being developed to measure deslorelin in serum at pg/ml concentrations. The next step will be to use clinical samples to better characterize serum levels and tailor administration to each species.

3.  Evaluation of the efficacy of Improvest® (GnRH conjugate vaccine, Zoetis®, Parsippany, NJ, USA), a new contraceptive method in giraffe (Giraffa camelopardalis), is currently underway by serial collection of non-invasive samples and eventually archiving tissues from necropsy.

4.  Transcervical biopsy, already validated in domestic dogs (Canis familiaris), is being assessed prospectively as a tool to evaluate early endometrial hyperplasia in non-domestic canids.1

As the zoo community works together to address the crisis in sustainability, it is critical to support both prospective studies and the responsible archival of biological specimens which will provide valuable insight into our continued efforts to manage reproduction.


The AZA Reproductive Management Center and its advisory board have been and continue to be a valued collaborator in all these studies. We also appreciate the great support that zoos, veterinarians, and pathologists have provided for these studies and the continued additions to the RHSP archive.

Literature Cited

1.  Christiansen BW, Schlafer DH, Agnew DW, Wang C, Kozlowski C, Asa CS. Diagnostic value of transcervical endometrial biopsies in domestic dogs compared with full-thickness uterine sections. Reprod Dom Anim. 2012;47(Suppl. 6):342–346.

2.  Goblet CC, Moresco A, Garner MM, Agnew DW, Newell-Fugate AE. Retrospective characterization of reproductive tract lesions in relation to age, parity, and contraception in captive suidae and tayassuidae. Theriogenology. 2019;127:137–144.

3.  Moresco A, Agnew DW. Reproductive health surveillance in zoo and wildlife medicine. J Zoo Wildl Med. 2013;44(4 Suppl):S26–33.

4.  Moresco A, Dadone L, Arble J, Klaphake E, Agnew DW. Location and removal of deslorelin acetate implants in female African lions (Panthera leo). J Zoo Wildl Med. 2014;45:397–401.

5.  Munson L, Harrenstien L, Haslem CA, Stokes JE. Update on diseases associated with contraceptive use in zoo animals. In: Proc Am Assoc Zoo Vet, Am Assoc Wildl Vet, and Wildl Dis Assoc. 1995:353–355.


Speaker Information
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Dalen W. Agnew, DVM, PhD, DACVP
Reproductive Health Surveillance Program
Michigan State University
East Lansing, MI, USA

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