Reintroduction increased vitamin E and condition in captive-bred yellow-footed rock wallabies Petrogale xanthopus

Abstract

Welfare implications of reintroduction are primarily unknown, although reportedly negative. Few studies have described physiological changes in captive-bred animals post-release and consequently the impact of reintroduction on captive-bred animals is not well understood. Such information is crucial to understanding whether reintroduction constitutes ethical practice. For these reasons two physiological indices associated with animal health, plasma vitamin E concentration (PVEC) or α-Tocopherol, and general condition scores, were monitored in reintroduced captive-bred yellow-footed rock wallabies Petrogale xanthopus celeris and P. x. xanthopus pre- and post-release. PVEC was chosen because deficiencies are common in captive animals compared to their wild counterparts, and have been linked to stress, myopathy, neuronal degeneration, low reproduction, anaemia and death. Changes in physical condition, within this study indicated principally by mass variation, coat condition, and reproductive status, but also parasite load, visible stress, lethargy and diarrhoea, have also not been reported for captive-bred animals reintroduced to the wild. Captive-bred yellow-footed rock wallabies reintroduced to areas of their former range in Queensland and South Australia showed a rapid and sustained increase in PVEC and physical condition, with post-release values significantly higher than pre-release captive levels. Post-release values for both parameters did not significantly differ from that of wild counterparts. Hence I conclude that there was no welfare implications related to the observed parameters in these reintroductions, rather the opposite.