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Virginia Cooperative Extension - Knowledge for the CommonWealth

Feed Management Practices That Limit Overfeeding Of Protein Can Be Evaluated By Monitoring MUN Levels

Dairy Pipeline: July 2007

Charlie Stallings
Extension Dairy Scientist, Nutrition & Forage Quality
(540) 231-3066;

Milk urea nitrogen (MUN) is a direct indicator of protein status of animals and can be used to predict over or under feeding. Factors that can influence MUN concentrations are: rumen degradable and undegradable protein intake, energy intake especially rumen available energy needed to capture rumen available N, heat damage resulting in reduced protein and energy digestibility, consumption of water because dehydration increases MUN, and feed sorting. Best management practices to prevent overfeeding of protein are:

Dr. Rich Kohn from the University of Maryland has lead a project working with milk cooperative labs reporting MUN’s in our region. Lab methods have been standardized resulting in uniform reporting. In other words, results from one lab should be comparable to another. Virginia Tech and Virginia Cooperative Extension are cooperating with this project and can supply technical support to herds that have abnormal levels. More information will be available in written format and on our web site (

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