Dr. Douglas R. Tolleson has been an Assistant or Associate Extension Specialist and Research Scientist for Rangeland Management at the University of Arizona from 2008 to 2016. Previous to his employment in Arizona, Dr. Tolleson directed the Grazingland Animal Nutrition Lab for Texas A & M University where he supervised daily operations and provided international training to scientists on the use of NIRS technology for nutrition of all classes of grazing animals. He also assisted in developing NUTBAL PRO nutritional support software.

Dr. Tolleson is a member of the Editorial Board for the Ruminant Nutrition Division for the Journal of Animal Science and serves as Liaison to the Society for Range Management for the American Society of Animal Science. He has published 27 refereed journal papers (10 as senior author), 36 other peer reviewed publications (14 as senior author), 116 abstracts (42 as senior author) and 30 popular press or newsletter articles. As principal investigator, co-investigator, or collaborator Dr. Tolleson has secured over $2.5 million in contracts and grants since 1999. He has advised or served on committees for 4 MS, 3 Ph.D., and 1 undergraduate honors student. Dr. Tolleson has delivered 33 invited talks or lectures and 135 extension presentations. He serves as a member of the Advisory Council, Western Center for Risk Management Education and has been a Director for the Natural Resource Conservation Workshop for Arizona Youth for 7 years. He served as President of the Arizona Section, Society for Range Management and was a co-awardee of the US Forest Service National Rangeland Research and Development Award in 2012. He has been recognized by his peers and administrators in Arizona as the Extension Faculty of Year in 2013. He received a B. S. in Animal Science, a M. S. in Physiology of Reproduction, and a Ph. D. in Rangeland Ecology and Management from Texas A & M University.