The Department for "Animal Nutrition and Rangeland Management in the Tropics and Subtropics" conducts research at animal, system and landscape level with the main aim of enhancing the resource-use efficiency and ecological sustainability of forage-based livestock production. The nutritional effects on the protein and carbohydrate fermentation and the efficiency of rumen microbial growth in the fore-stomachs of ruminants are studied in in vitro and in vivo experiments, as well as on-farm studies to explore the role of livestock in integrated and/or pastoral agroecosystems. Environmental and management impacts on the feeding behavior of herbivores and the yield and composition of the pasture vegetation are analyzed in grazing experiments to understand possible plant-animal interactions. Research of the working group combines innovative analytical methods, modeling tools, and non-invasive sensor and marker techniques and currently focuses on farming systems of East Africa and South America.