Assessing kangaroo health FOR DUMMIES

Eastern grey kangaroos (Macropus giganteus) from Nelson Bay Golf Course, New South Wales, Australia

By Maquel Brandimarti, The University of Sydney

Understanding the health and welfare of wildlife is critical as humans expand development and agriculture, and climate change threatens ecosystems. Health and welfare tools must allow managers to rapidly assess health with accuracy, but these tools are lacking. In our paper we establish a robust tool for wildlife managers to assess health, detect dietary shifts and nutritional stress, predict survival and diagnose parasite infections, all with minimal impact on the animal’s survival. To do this we describe baseline haematological and serum protein reference intervals using clinically healthy kangaroos from 11 wild populations (n = 514) spanning more than 1000 km of their geographic range. The number of individuals that fall outside of the reference interval provides a quantifiable measure of the impact of parasites, disease and physiological stressors within a population.

The eastern grey kangaroo is an iconic, highly managed marsupial in Australia, but decisions over its management can be divisive. Therefore, developing an objective tool to assess kangaroo health and welfare would be useful in making decisions on kangaroo management. Below are our guidelines and recommendations for using our reference interval for your kangaroo and/or population:

Sampling target:

• Aim to capture a representative sample across different demographic classes of the target population (i.e. equal proportions adult and subadult animals)
• Standardise sample collection, handling and processing of animals, consistent for the species
• When assessing population health, sample as many individuals as possible (at least 120 individuals is ideal but often not feasible for wildlife populations)

Sampling timeframe:

• Populations should be surveyed within a defined time period ideally within one season of one year, to coincide with similar weather patterns
• Analyse samples as a batch at the same laboratory

Kangaroos are chemically immobilised using an X-Calibre dart gun before processing.

Using our reference intervals:

• Select the relevant eastern grey kangaroo reference interval table for comparison with your values (options include: species only, maturity or season specific)
• If sampling permits, we recommend our maturity specific reference interval (Table 3 in our paper) to be used initially for the relevant age cohort

Release of a kangaroo after a health check. The tail is held to stabilise the animal. Image provided by Angie Jarman.

We also investigated the impacts of site and climate on parameters of health in eastern grey kangaroos. We found that site-specific environmental factors such as rainfall were shown to be the most important factors affecting blood parameters of health in kangaroos. As such, consideration of these factors is paramount as climate change impacts local and site-specific climatic features. Therefore, we urge users of the reference interval to consult our site-specific population means when specific site attributes are of interest to you; for example, if your population density is high, there is endemic disease or animals are captive.

We hope our tool will be used by wildlife managers to assist in the diagnosis of disease and management of animal health to maintain a balance in our ecosystems.

Access our reference intervals or read the paper here

Maquel Brandimarti, The University of Sydney

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