Providing a quantitative/modelling perspective on animal feeding systems and feed evaluation, this text is designed as a reference tool for researchers and advanced students. It describes feed evaluation methods, modern feeding systems and mathematical modelling. Topics covered include: feed characterization, intake, passage and digestibility; in situ and in vitro digestion techniques; calorimetry and slaughter trials. Also covered are: modern feeding systems for dairy cows, beef cattle, sheep and goats, pigs, poultry and horses. The text describes mathematical modelling in feeding systems, including: prediction of response to nutrients by farm animals, whole rumen function; the lactating dairy cow; growth and wool production in ruminants; lactation in pigs; egg production and growth in poultry; and growth in fish.