The annual Halver Lecture in Comparative Nutrition was presented to a live audience on February 22, 2022. Students, faculty, and staff packed the Todd Hall auditorium to listen to nutritionist Dr. Troy Tollefson from Mazuri® Exotic Animal Nutrition explain how research in comparative animal nutrition improves the health, well-being, and longevity of animal species in zoos and other facilities around the world.
Three-times a Coug!
Tollefson is truly a Coug, earning three degrees at WSU – BS and MS degrees in Zoology and a PhD in Natural Resource Science! He finished his undergraduate education in 2002. The time he spent volunteering with the bears as an undergraduate student opened the door to his first post-graduate degree where he studied the spatiotemporal overlap of grizzly bears and humans in Alaska for his MS thesis in 2004. Then, he earned his PhD in 2007 with research examining how forage quality influences body condition and reproduction of mule deer.
His WSU training led to his position as the first nutritionist at Busch Gardens/SeaWorld Parks in Tampa, Florida, where he was responsible for the nutrition of hundreds of species.
“The educational foundation I received at WSU made it possible for me to learn and educate myself about other species and become an ‘instant’ expert,” he said.
In his current position at Mazuri® Tollefson now has a larger impact on animal nutrition. Mazuri® develops new and reformulates existing diets for all types of exotic animals, including anything from insects, elephants, fish, and everything in between.
Collaborative relationships for research
Mazuri® does not have the research facilities to develop and test diets for most of the species they work on, although, their parent company Land O’Lakes/Purina Mills, has a research farm focused on domestic animals. So, the company relies on collaborations with research partners at universities, zoos, and farms to conduct most of their research. Because exotic animals are often unavailable, comparative nutrition studies using model animals that have physiologically similar digestive systems are used to test diets. For example, horses were used to test the hypothesis that phytoestrogens, found in high concentrations in common feed sources such as alfalfa, soy, and clover, may negatively affecting estrous cycles in white rhinoceroses.
Historically, exotic animal diets were formulated based on research with domestic animals and unfortunately, those animals did not thrive, did not always reproduce well, and often died prematurely. However, as nutritional scientists and researchers learn more about needs of exotic species, dietary ingredient compositions have become fine-tuned to meet specific requirements for starch, fiber, protein, energy, vitamins, and minerals to prevent health issues like thin body condition scores, poor coat condition, ruminal acidosis, bloat, and suboptimal reproductive performance.
Tollefson said that exotic animal diets cannot be replicated exactly because it is impossible to know exactly what a species is eating in the wild. Instead, he balances diets to meet their known nutritional requirements and works closely with veterinarians, animal caregivers, scientists, other nutritionists, and feed mill operators to ensure diets contain high-quality ingredients, are accepted by the animal, and practical for the animal caretaker to feed.
Halver’s legacy to comparative nutrition
Once again, the Halver Lecture exposed students of animal sciences to another person’s experiences in the exciting field of comparative nutrition. The department is grateful to the late Dr. John E. Halver, III (1922 – 2012), a WSU alumnus, and his family for funding this annual event. We were especially happy that Dr. Halver’s son Peter was able to come to Pullman and attend the lecture this year.