The dynamics of nutrient degradation in the reticulorumen and of nutrient digestion in the intestines are major determinants of the utilization of diet ingredients by ruminants. These dynamics of nutrient digestion should be known and controlled to improve ruminal and total tract digestibility and to optimize production and composition of milk and meat | 24 Feed Processing Effects on Nutrient Degradation and Digestibility . Van der Poel 1 E. Prestlokken2 and . Goelema3 1Wageningen University Animal Nutrition Group Marijkeweg 40 6709 PG Wageningen The Netherlands 2Felleskj0pet Forutvikling Department of Animal and Aquacultural Sciences Agricultural University of Norway PO Box 5003 N-1432 As Norway 3Pre-Mervo PO Box 40248 3504 AA Utrecht The Netherlands Introduction The dynamics of nutrient degradation in the reticulorumen and of nutrient digestion in the intestines are major determinants of the utilization of diet ingredients by ruminants. These dynamics of nutrient digestion should be known and controlled to improve ruminal and total tract digestibility and to optimize production and composition of milk and meat. A careful and appropriate selection of concentrate ingredients to meet the required supplementation of the forage could fulfil this objective. Moreover the processing of feeds can be used to manipulate the nutrient degradation characteristics in the rumen and the site of nutrient digestion being a helpful tool to optimize ruminant diets. Amongst other nutrients protein and starch are important diet constituents for ruminant diets. Protein appearing in the small intestine of the ruminant originates from dietary protein escaping microbial degradation in the rumen and from protein synthesized by microbes in the rumen. Dietary starch is either degraded to volatile fatty acids in the rumen yielding energy for synthesis of microbial protein or digested as glucose in the small intestine see Chapters 7 and 10 . The quality and the content of protein and starch may greatly affect the nutritional responses to the diet. Protein and starch account for a considerable part of the diet costs and a balanced supply of protein and total carbohydrates is important to minimize output of nitrogen in faeces and urine. Thus optimizing the supply of these nutrients by processing can be important to maximize the financial
