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This NebGuide explains how to properly test for MUN and interpret the results.
Milk urea nitrogen (MUN) analyses can be used as a signal, or "red flag", to point out potential problems in your feeding program. In particular, high MUN values reflect excessive dietary crude protein or low rumen degradable nonfiber carbohydrates (NFC). The NFC fraction, usually composed of starch and other sugars, can be low when insufficient grain is fed, or grain is improperly processed. Appropriate MUN testing over a period of several months to fine tune a feeding management program can result in:
1. precisely meeting nutritional requirements,
2. lower feed costs,
3. increased reproductive performance,
4. increased milk protein yield, and
5. minimal nitrogen excretion into the environment.