This book contains the proceedings of the XIth International Symposium on Ruminant Physiology. The papers address ruminant comparative physiology, the rumen ecosystem and metagenomics, nutrient digestion and absorption, methanogenesis, tissue metabolism and gene expression, pregnancy, lactation and growth, adaptation to heat-stress, nitrogen use, nutrition and reproduction, nutrition and welfare and nutrition for sustainable ruminant production. These topics are in line with the current challenges for animal breeding: production efficiency, meat and milk quality, environment (greenhouse...