He teaches animal nutrition and forage related courses, primarily Applied Nutrition, Ruminant Nutrition, and Pastures and Forages. His research primarily focuses on ruminant nutrition and grazing systems dealing with both small and large ruminant animals. He has been the PD or Co-PD of several research projects funded by USDA, NIFA, and NRCS, and has numerous research articles published. Caldwell has been a review author for The Professional Animal Scientist, has been an invited speaker at different conferences, and is involved in national collaborative projects.