How are blood tests used to improve the welfare of whales and dolphins?

When a doctor looks at your blood test, how do they know if your blood values are normal? Healthcare professionals use normal reference intervals as a guideline to interpret your test results. The lab provides your healthcare professional with a normal range of values that test results should fall between for healthy adults. Test results showing your values are higher or lower than the normal range will assist your health professional in developing a treatment plan or signal them to take a closer look at certain aspects of your health. Our veterinarians use a similar process when doing health checkups on the animals cared for at Brookfield Zoo.
Healthy reference intervals are one of the many tools that the veterinarians use to assess an individual’s health and welfare. These can be particularly helpful because animals cannot verbalize how they are feeling. Therefore, animal care staff and veterinarians must infer how they are feeling from their behavior, physical examinations, and their lab test results. All of the dolphins at Brookfield Zoo are trained to voluntarily participate in blood sampling. These blood samples are tested as part of our routine health monitoring program. Having a robust set of healthy blood reference intervals to regularly compare to blood test results improves our veterinarians’ ability to identify any anomalies and take a closer look if needed.

Animal care staff practicing a voluntary blood sampling behavior with one of the bottlenose dolphins.
As part of the Cetacean Welfare Study, we received blood samples from 174 healthy common bottlenose dolphins (Tursiops truncatus), 27 Indo-Pacific bottlenose dolphins (Tursiops aduncus), 13 beluga whales (Delphinapterus leucas), and 6 Pacific white-sided dolphins (Lagenorhynchus obliquidens) in zoos and aquariums accredited by the Alliance for Marine Mammal Parks and Aquariums and the Association of Zoos & Aquariums. The blood samples were tested at laboratories in the United States and Mexico for up to 56 hematologic, serum, and plasma biochemical variables.Animal care staff compare the dolphin’s blood test results on the computer with the reference intervals provided in the mobile ZooPhysioTrak app.
We generated normal reference intervals that include any differences due to an individual’s sex and age as well as the month the sample was collected. Importantly, the reference intervals are generated from healthy dolphins residing in 43 different accredited zoos and aquariums. The participant’s diverse living situations means that the results can be better used to assess future blood samples. To make sure the intervals are easily and quickly accessible by animal care staff and veterinarians, we built an iOS app called ZooPhysioTrak to house the health information. ZooPhysioTrak is a new resource for veterinarians to compare their individual whale and dolphin hematological, serum, and plasma biochemical test results to the wider population living in accredited zoos and aquariums. The reference intervals were also published in the peer-reviewed journal PLoS One. If you would like to learn more about our findings and read a detailed discussion of the blood test results, the paper is available here.

Lisa Lauderdale, Ph.D.
Animal Welfare Scientist
Published November 1, 2022