Nutritional strategies to improve nitrogen efficiency and milk protein synthesis in dairy cows

James D. Ferguson

• Publisher: Burleigh Dodds Science Publishing
• Year: 2016
• eBook ISBN: 9781838791384
• Topic: Tecnología e ingeniería
• Subtopic: Agricultura sostenible

Dairy production is associated with significant losses of nitrogen to the environment, contributing to the degradation of air and water systems. These losses must be decreased to make dairy farming sustainable, and a primary means of doing this is to increase the conversion of feed protein into milk protein. This chapter considers the two nitrogen-utilising systems in the cow: the rumen microbiota and ruminant tissues. The more efficient both the rumen and tissue systems are, the lower the urinary nitrogen excretion. We review approaches to estimating rumen microbial protein synthesis, the protein and energy requirements of dairy cows and the use of milk urea nitrogen (MUN) to assess the nitrogen efficiency of dairy cows. We then consider the development of nutritional systems which account for rumen microbial synthesis, rumen-degradable and undegradable feed protein and endogenous protein supplies of amino acids based on utilisation of feed inputs.

Table of contents

• 1 Introduction: the importance of reducing nitrogen losses in dairy farming
• 2 Protein in milk: protein content, determining factors and method of synthesis
• 3 Abomasal and duodenal infusion studies
• 4 Ideal amino acid profile
• 5 Central issues in estimating rumen microbial protein synthesis
• 6 Additional factors in estimating microbial protein synthesis
• 7 The metabolisable protein requirements of dairy cows
• 8 Milk urea nitrogen as a diagnostic tool
• 9 Designing rations to improve N efficiency in dairy cows
• 10 From research trials to real farm applications
• 11 Conclusion
• 12 Where to look for further information
• 13 Glossary of abbreviations
• 14 References