Eastern Wisconsin Dairy Herd Impovement Coop

Monitoring Milk Urea Nitrogen (MUN) in milk is an excellent quality control tool for managing your milking herd's nutrition. AgSource offers two report options to meet your business needs. The Management MUN Summary is the ultimate tool for monitoring rations because the raw MUN values are adjusted for a variety of factors, so there is no need to establish a base line. The Conventional MUN Summary provides the raw values with no adjustment.

Management MUN is the product of recent research on over 400,000 AgSource MUN records studied by dairy scientists at the University of Wisconsin-Madison. Researchers found that cows metabolize protein quite differently based on a number of factors. For example, herds sampled in the evening average a full mg/dl higher MUN than those tested in the morning. The average Holstein MUN was 12.8 mg/dl while Brown Swiss averaged 14.6 and Jerseys averaged 14.4.

There are also large variations based on season. Past MUN interpretation guidelines, recommending establishing a baseline MUN over several months, are found to be counterproductive. In addition, typical MUN values increase as milk production rises to 85 pounds per day. First and later lactation cows have significantly different MUN values, as well. A smaller factor affecting a cow's MUN is frequency of milking. AgSource's Management MUN Summary is the world's only MUN tool that takes all of these variables into consideration.

The Management MUN Summary is designed as a ration evaluation tool. Dairies feeding multiple rations may want to have separate Management MUN Summaries run for each group. Using AgSource's Temporary Strings Option, you can move cows into different strings (groups) each month to mirror the actual movement of your herd into different pens.

Each cow has her Management MUN calculated. The Management MUN Summary graphs illustrate how well the ration fits that particular group of cows. Management MUN calculations are only available for Holsteins, Jerseys and Brown Swiss.

During the first 35 days in milk, the Management MUN values are affected more by fat mobilization and the transition period than the current ration cows are eating. Consequently, Management MUN is only calculated for cows that have been milking more than 35 days.

Management MUN Summaries are Optional Reports available exclusively to AgSource members. In addition to the report charge, there also is a charge for the individual cow MUN analysis.

Management MUN explanations

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Click on the individual areas for detailed information

Click here for frequently asked questions about Management MUN

Block A

This graph illustrates the percentage of cows at each unit level of Management MUN. The graph also includes a highlighted area from 10-14 milligram/deciliter. This range has been identified by researchers as the normal or desired MUN range for lactating cows.

It may not be realistic to expect all your cows to be in this desired range all of the time. Changing your ration if most of your cows are in the Desired Range and a relatively even percent of cows is both high and low is probably not warranted. However, if your group of cows is skewed with a high proportion outside of the normal MUN range, you should strongly consider adjusting the group's TMR.

MUN values below the 10 mg/dl may indicate one or more of the following factors about the ration they are eating - along with possible solutions:

The protein level is low - add more rumen degradable protein
Rumen fermentable non fiber carbohydrate levels are high - replace shelled corn with whole cottonseed
The ration's energy level is high - remove fat or high energy feeds such as shelled corn

MUN values over 14 mg/dl may indicate one or more of the following factors about the ration they are eating - along with possible solutions:

The protein level is high - reduce rumen degradable protein
Rumen fermentable non fiber carbohydrate levels are low- add shelled corn
The ration's energy level is low - add fat or high energy feeds such as shelled corn

Conventional MUN Reports are are Optional Reports available to AgSource members. In addition to the report charge, there is also a charge for the individual cow MUN analysis

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Block B

The desired MUN range of 10-14mg/dl is highlighted. The bar graph illustrates how first and later lactation cow's MUN averages for this ration group have reacted over the past three tests.

Your group's makeup is constantly changing with some cows leaving and others entering the group. However, you can still track the results of any ration adjustments you have made and how they have affected the group's Management MUN.

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Block C

CURRENT TEST AVERAGE DIM / MUN LEVEL

This block identifies the average days in milk of cows at each MUN level in Block A.

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Block D

This table contains the average Actual MUN (raw value) and the Average Management MUN (adjusted value) of first lactation and second and greater cows over the past three test days.

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Block E

LOW MGT. MUN COWS <10 mg/dl;
HIGH MGT. MUN COWS >14 mg/dl

This table allows you to track low and high Management MUN cows by lactation over the past three months. This enables you to track results from ration changes you have made over these periods and how the changes have affected these outlier groups. A close examination of outliers will generally provide more information than simple averages. The tables include:

Test Date
Avg. Mgt. MUN - Average Management MUN of the cows in this high or low group
% Total Group - Percent of the total group in the low or high MUN range.
Average DIM - Average days in milk for the cows in this group.

Block A provides a visual graphic illustration of your herd or group Management MUN distribution. This block quantifies the percent of cows that are outliers (<10 mg/dl or >14 mg/dl).

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Nutritional Management

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Block A

Block B

Block C

Block D

Block E