Induction of synchronous oestrus but not ovulation after pre-treatment with the GnRH agonist, Lucrin® Depot, in the tammar wallaby

Modeling genetic benefits and financial costs of integrating biobanking into the conservation breeding of managed marsupials

Managed breeding programs are an important tool in marsupial conservation efforts but may be costly and have adverse genetic effects in unavoidably small captive colonies. Biobanking and assisted reproductive technologies (ARTs) could help overcome these challenges, but further demonstration of their potential is required to improve uptake. We used genetic and economic models to examine whether supplementing hypothetical captive populations of dibblers (Parantechinus apicalis) and numbats (Myrmecobius fasciatus) with biobanked founder sperm through ARTs could reduce inbreeding, lower required colony sizes, and reduce program costs. We also asked practitioners of the black-footed ferret (Mustela nigripes) captive recovery program to complete a questionnaire to examine the resources and model species research pathways required to develop an optimized biobanking protocol in the black-footed ferret. We used data from this questionnaire to devise similar costed research pathways for Australian marsupials. With biobanking and assisted reproduction, inbreeding was reduced on average by between 80% and 98%, colony sizes were on average 99% smaller, and program costs were 69- to 83-fold lower. Integrating biobanking made long-standing captive genetic retention targets possible in marsupials (90% source population heterozygosity for a minimum of 100 years) within realistic cost frameworks. Lessons from the use of biobanking technology that contributed to the recovery of the black-footed ferret include the importance of adequate research funding (US$4.2 million), extensive partnerships that provide access to facilities and equipment, colony animals, appropriate research model species, and professional and technical staff required to address knowledge gaps to deliver an optimized biobanking protocol. Applied research investment of A$133 million across marsupial research pathways could deliver biobanking protocols for 15 of Australia's most at-risk marsupial species and 7 model species. The technical expertise and ex situ facilities exist to emulate the success of the black-footed ferret recovery program in threatened marsupials using these research pathways. All that is needed now for significant and cost-effective conservation gains is greater investment by policy makers in marsupial ARTs.

Emerging arguments for reproductive technologies in wildlife and their implications for assisted reproduction and conservation of threatened marsupials

Assisted reproductive technologies (ARTs) have significant potential to make a meaningful contribution to the conservation of threatened wildlife. This is true of Australia's iconic, and endangered koala (Phascolarctos cinereus). If developed, ARTs could offer a solution to manage genetic diversity and costs in breeding programs and may provide frozen repositories for either insurance or the practical production of genetically resilient koalas for release and on-ground recovery. Holding back the wider use of ARTs for koalas and other wildlife is a lack of funding to close the remaining knowledge gaps in the marsupial reproductive sciences and develop the reproductive tools needed. This lack of funding is arguably driven by a poor understanding of the potential contribution ARTs could make to threatened species management. We present a review of our cross-disciplinary and accessible strategy to draw much needed public attention and funding for the development of ARTs in wildlife, using emerging cost and genetic modelling arguments and the koala as a case study.

Human chorionic gonadotrophin does not induce ovulation in the tammar wallaby

We investigated whether human chorionic gonadotrophin (hCG), rather than porcine luteinising hormone (pLH), could induce ovulation in the tammar wallaby (Notamacropus eugenii) after priming with pregnant mare serum gonadotrophin (PMSG). pLH is effective, but is more expensive and supply is problematic. On Day 0 pouch young were removed (RPY) and 5mgkg−1 of bromocriptine mesylate was administered to all non-pregnant wallabies (n=12) to reactivate an oestrous cycle. On Day 20 RPY each female received 20IU PMSG i.m. and three days later (Day 23 RPY), the Single-Dose group (n=6) received 500IU of hCG suspended in oil at 0900 hours, and the Multi-Dose group (n=6) received 500IU of hCG at 0900, 1230 and 1630 hours. From Day 25 to Day 28 RPY copulatory plugs were observed in the Single-Dose (n=4 of 6; Day 25.3 to 28.3 RPY) and Multi-Dose (n=5 of 6; Day 25 to 28 RPY) groups. Autopsy on Day 31 RPY revealed that all females had reactivated, and despite all having large preovulatory follicles (4–6mm) in both ovaries, no ovulations or embryos were observed. We conclude that hCG is not an effective source of exogenous LH for the induction of ovulation in the tammar wallaby.