Expanding Chicago Zoological Society's Welfare Monitoring Toolkit

Our Animal Welfare Research Team is focused on tracking physiological biomarkers, such as the glucocorticoid:DHEA ratio, to provide insight into an animal’s physical, mental and emotional health. Our Endocrinology Lab has already tracked glucocorticoid metabolites for over 50 species, and we plan to validate assays that will allow us to measure DHEA across diverse taxa.

Greetings from the Chicago Zoological Society’s Animal Welfare Biologist!

When people ask what my job entails, I say that one of the Animal Welfare Research Team’s main goals is to identify new methods for continuously improving the welfare of individual animals. This involves developing tools for monitoring various aspects of welfare – including an individual’s physical, emotional and mental states. Furthermore, it is crucial that we try to employ measures that do not require invasive sampling (e.g. blood draws) or handling on a regular basis.
These days, our team is focused on integrating physiological biomarkers that provide insight into an animal’s physical condition, psychological health and overall welfare status. Most commonly, zoo welfare researchers rely on glucocorticoid hormones (cortisol, corticosterone) for assessing welfare. Fortunately, we are able to non-invasively track glucocorticoids (or their metabolites) by analyzing feces, urine, saliva, feathers, hair, fingernails, claws and even skin secretions! While glucocorticoids give us information about the body’s stress response, there are limitations to monitoring this measure alone. To paint a more complete picture, we are exploring the use of dehydroepiandrosterone (DHEA) – which has been described as an “antagonist” of glucocorticoids. There is evidence DHEA has anti-aging, immune-enhancing properties and that high levels are associated with good mental health. Humans even take DHEA supplements with hopes of building strength, boosting immunity, improving memory, slowing the aging process and enhancing well-being!

Dolphins are just one of the species that we plan to monitor using the glucocorticoid:DHEA ratio. For this species, DHEA can be tracked by analyzing fecal samples.

We are excited about the prospect of using the ratio of glucocorticoids to DHEA to monitor welfare across a wide array of species. Studies on both domestic and exotic animals have found that the ratio can give us insight into an individual’s physical state, mental health and overall welfare. For example, research on farm animals has shown that healthy individuals have a lower cortisol:DHEA ratio than those who are unhealthy, and that dealing with stressful events and new environments can lead to an elevated ratio.
While our lab has successfully tracked glucocorticoid metabolites for over 50 species, DHEA is a new frontier for animal welfare scientists. The good news is that other researchers have found that DHEA circulates in a variety of species including rabbits, dogs, pigs, sheep, horses, birds and primates. We are committed to monitoring this hormone non-invasively in zoo animals. We have already validated assays that will allow us to measure DHEA by analyzing the feces of cetaceans and white-bellied pangolins.
Our ultimate goal is to investigate how the glucocorticoid:DHEA ratio varies in response to both positive events and negative situations. To do this, we will have to combine the ratio with other welfare indicators, such as behavioral data and other physiological biomarkers (e.g. Immunoglobulin-A). Adding the glucocorticoid:DHEA ratio to our “welfare monitoring toolkit” will not only benefit the individuals currently living at Brookfield Zoo but will also help improve care at other zoo facilities.   
Dr. Jessica Whitham
Animal Welfare Biologist


Posted: 9/23/2019 11:39:04 AM by Sean Keeley

CZS & Brookfield Zoo

Since the opening of Brookfield Zoo in 1934, the Chicago Zoological Society has had an international reputation for taking a cutting-edge role in animal care and conservation of the natural world. Learn more about the animals, people, and research that make up CZS here at our blog.


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