Analysis of rumen liquor for fraction of VFAs enzymatic activity of various metabolites and estimation of rumen fluid volume and its flow rate are covered in depth. It was followed by estimation of anti-nutritional / toxic factors in various un-conventional feeds using HPLC / Spectrophotometer, detail analysis of milk and body condition scoring for dairy cattle are included as assessment of these parameters are important in Ruminant Nutrition Research. Necessary practical work is included; the exhaustive details have been avoided, since the manual is primarily meant for postgraduate scholars, teachers, scientists and feed industry personnel use.