Postmortem Collection of Gametes for the Conservation of Endangered Mammals: A Review of the Current State-of-the-Art

Simple Summary Many species are threatened with extinction. A consequence of the decreasing population sizes is the loss of genetic diversity. To maintain this genetic diversity, establishing genetic resource banks can be part of the solution. These banks contain, amongst others, sperm and oocytes, which can be used to produce offspring through artificial reproduction techniques. Deceased animals can be an important source for the collection of these gametes, without having a negative effect on living animals. To transport, collect, and store gametes of wildlife correctly, gametes of domestic animals can possibly be used to examine the ideal procedures. To date, sperm has been collected after death from at least 28 wildlife species and oocytes have been collected from at least 10 wildlife species of the Equidae, Bovidae, and Felidae families. Using these postmortem collected gametes, offspring have been produced in two wildlife species, both belonging to the Bovidae. This shows that gametes recovered postmortem can indeed be a valuable resource for the conservation of endangered species. The collection of gametes from recently deceased domestic and wildlife mammals has been well documented in the literature. Through the utilization of gametes recovered postmortem, scientists have successfully produced embryos in 10 different wildlife species, while in 2 of those, offspring have also been born. Thus, the collection of gametes from recently deceased animals represents a valuable opportunity to increase genetic resource banks, obviating the requirement for invasive procedures. Despite the development of several protocols for gamete collection, the refinement of these techniques and the establishment of species-specific protocols are still required, taking into account both the limitations and the opportunities. In the case of wildlife, the optimization of such protocols is impeded by the scarcity of available animals, many of which have a high genetic value that must be protected rather than utilized for research purposes. Therefore, optimizing protocols for wildlife species by using domestic species as a model is crucial. In this review, we focused on the current advancements in the collection, preservation, and utilization of gametes, postmortem, in selected species belonging to Equidae, Bovidae, and Felidae, both domestic and wildlife.