Birth of Koalas (Phascolarctos cinereus) at Lone Pine Koala Sanctuary following artificial insemination
Johnston, SD, McGowan, MR, O’Callaghan, P, Cox, R, Houlden, B, Haig, S & Taddeo, G 2003, International Zoo Yearbook, vol. 38, no. 1, pp. 160-172.
In May 1998, Lone Pine Koala Sanctuary announced the birth of the first koala produced by artificially inducing ovulation and artificial insemination. The success of this procedure was a first not only for the koala, but any marsupial species. An additional five koalas were also confirmed to be produced by artificial insemination.
Seventeen female koalas were used as subjects for two artificial insemination trials between December 1997 and March 1998. For the first trial, a ‘teaser’ male was introduced to nine females and coitus permitted to commence but then interrupted before ejaculation occurred. This process was previously discovered to induce ovulation in females, which successfully occurred in this trial. Two different methods of artificial insemination were then attempted on the nine females. Five of the females were inseminated using a ‘Cook insemination catheter,’ which was specifically designed for depositing semen into the upper urogenital sinus. The remaining four females were inseminated while anaesthetised using a ‘Tom-cat catheter,’ which enabled the visualisation of the uppermost region of the urogenital sinus for semen deposition. The former method resulted in two births, and the latter method in three. In the second trial, eight females were injected with 250 International Units of human chorionic gonadotrophin (hCG), which induced ovulation before the koalas were artificially inseminated using the same methods described above. This trial resulted in one birth as a result of urogenitoscopic insemination using the ‘Tom-cat catheter’, which was the first recorded birth of a marsupial as a result of a combination of hormonally-induced ovulation and artificial insemination.
Although the urogenitoscopic method was more successful in achieving pregnancy than the alternative method in these trials, further investigations would be required to determine whether one method is, in fact, superior to the other. The ‘Cook insemination catheter’ is preferred over the ‘Tom-cat catheter’ as it can be used while the female koala is conscious and therefore requires neither anaesthesia nor the use of tools to visualise the openings of the lateral vaginae.
This study followed a series of related investigations that aimed to improve understandings of and techniques in the reproductive management of both captive and wild koala populations. Programs employing assisted breeding technologies have been successfully established in the past for eutherian species, but not for marsupial species. The development of an artificial insemination program such as that described in this study is significant in many ways for the conservation of koalas; most notably, by describing new tools for reproductive and genetic management, and by creating opportunities for the proactive management of koala populations.
Summarised by Joanna Horsfall
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