Management of isolated populations of western grey kangaroos (Macropus fuliginosus ocydromus) through fertility control, in south-western Australia

[Truncated abstract] This thesis explores the general hypothesis that management of isolated populations of western grey kangaroos (Macropus fuliginosus ocydromus) in south-western Australia by chemical fertility control through a capture, mark and treat approach is a practical alternative to culling, which is becoming socially unacceptable. For all live animal studies I used 'kangaroo muesli', a proprietary mix consisting mostly of steam-rolled lupins flavoured with molasses, and lucerne hay, to facilitate close approach to the kangaroos. To capture the kangaroos, I gave them an intra-muscular injection of tiletamine/zolazepam (Zoletil®), which induces unconsciousness rapidly. Unfortunately, it also has a prolonged recovery time, of up to four hours. While this is acceptable for a research situation it is not suitable for general field application. A practical alternative for minor procedures would be immobilisation of the kangaroos with succinylcholine, but there is no safe, efficacious dose known for kangaroos. To predict a safe, efficacious dose of succinylcholine for kangaroos, I compared plasma cholinesterase activity of western grey kangaroos with that of horses, sheep and cattle, for which succinylcholine dose rates are well established, and determined that as the plasma cholinesterase activity of kangaroos was similar to that of sheep and cattle, the succinylcholine dose should be too.