Artificial insemination in the koala: the how and why
Johnston, SD & O’Callaghan, P 2001.
The first birth of a koala, and indeed a marsupial, as a result of artificial insemination (AI) occurred at Lone Pine Koala Sanctuary in 1998, and an additional five koalas were later confirmed to be born following AI. In this presentation, Johnston and O’Callaghan provide an overview of their many developments in establishing protocols and techniques for the successful production of young in captive koalas via AI.
In the koala AI process, there are three major hurdles to be overcome: (1) collecting, manipulating and preserving semen; (2) selecting a suitable time in the oestrous cycle for insemination; and (3) depositing inseminate at a suitable site to increase the likelihood of conception. The preferred method for collecting koala semen is with an artificial vagina, which the penis is directed into during a natural mating interaction. The collected sample can then be used to inseminate an oestrus female after ovulation has been induced either pharmaceutically or by the physical stimulus of copulation. The female is inseminated by depositing the sample into the upper urogenital sinus using either an AI catheter or a urogenitoscopic technique. These three stages in AI are described in greater detail in the authors’ previous works1.
Numerous external factors are equally important to the success of an AI program for koalas. The first is the ability to access ‘normal’ animals to act as scientific subjects. In this regard, large captive populations such as that at Lone Pine Koala Sanctuary are ideal as several animals are available for use as semen donors or ‘teaser’ females. The second factor is the cooperation of keepers and veterinary staff. These collaborators are essential for carrying out manipulative procedures, maintaining accurate records, and their unique insights about the population’s individual animals. The third factor is the support of the institution through the provision of key resources. The fourth factor is effective collaboration between researchers and practitioners. The final factor is, of course, the koala itself. The authors believe that the demonstrated success of the AI program for koalas is unlikely to be repeated for any other marsupial. The koala is considered to be particularly suited to such a program given its placid nature, tractability in captivity, tolerance of manipulative and medical procedures, and unique oestrous patterns.
Developing artificial breeding technologies for koalas has the benefits of improving understandings of the species’ reproductive biology, creating alternatives to the transportation of live koalas for introducing genetic material into populations, overcoming infertility as an obstacle to reproduction, and informing similar programs for other species. Most importantly, however, assisted breeding via AI is a form of ex situ conservation that can help to reinforce and perhaps re-establish wild populations, and is therefore expected to play a vital role in future conservation efforts for this threatened species.
- Johnston, SD, McGowan, MR & O’Callaghan, P 1999, Assisted breeding technology for the conservation and propagation of Phascolarctos cinereus or how to make a koala pouch young, Proceedings of the Postgraduate Committee in Veterinary Science, Sydney, pp. 199-217.
Summarised by Joanna Horsfall
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