There are tremendous benefits to feeding ruminants nitrogen and phosphorus supplements, in terms of milk production and productivity. However what goes in, must also come out. Nitrogen and phosphorus excretions from dairy cattle are a major environmental pollutant. This book describes the latest knowledge in nitrogen and phosphorus nutrition of cattle including requirements, ruminal and total tract metabolism, possibilities of increasing the efficiency of nitrogen utilization and reducing nitrogen and phosphorus excretions from dairy and beef operations. It also includes aspects of the effects of dietary nitrogen and phosphorus on the reproductive efficiency of cattle.

Table of Contents:
1: Interactions between Cattle and the Environment: AGeneral Introduction, E Pfeffer, Institut fur Tierernährung,Bonn, Germany, and A N Hristov, University of Idaho,Moscow, USA 2: Nitrogen Requirements of Cattle, C G Schwab, Universityof New Hampshire, Durham, USA, P Huhtanen, MTTAgrifood Research Centre, Jokionen, Finland, C W Hunt,University of Idaho, Moscow, USA, and T Hvelplund,Institiute Agricultural Sciences, Tjele, Denmark 3: Nitrogen Metabolism in the Rumen, N D Walker,AgResearch, Palmerston North, New Zealand, C J Newbold,University of Wales, Aberystwyth, UK, and R J Wallace,Rowett Research Institute, Aberdeen, UK 4: Factors Affecting the Efficiency of Nitrogen Utilization inthe Rumen, A N Hristov, J-P Jouany, Inst National de laRecherche Agronomique, Saint Genes Champanelle, France 5: Whole Animal Nitrogen Balance in Cattle, J L Firkins,Ohio State University, Columbus, USA, and C Reynolds,Ohio State University, Wooster, USA 6: Phosphorus Metabolism in the Rumen, R L Kincaid,Washington State University, Pullman, USA, andM Rodehutscord, Martin-Luther-Universitat HalleWittenberg, Germany 7: Phosphorus Metabolism in Ruminants and Requirementsof Cattle, E Pfeffer, D K Beede, Michigan State University,East Lansing, USA, and H Valk¸I D TNO Animal Nutrition,Lelystad, The Netherlands 8: Effects of Dietary Phosphorus and Nitrogen on CattleReproduction, J D Ferguson, University of Pennsylvania,Philadelphia, USA, and D Sklan, Hebrew University,Rehovot, Israel 9: Improving the Efficiency of Nutrient Use on CattleOperations, J Schröder and A Bannick, WageningenUniversity and Research Centre, Wageningen, TheNetherlands, R Kohn, University of Maryland, College Park,USA