|
|
MUN Testing
MUN
(Milk Urea Nitrogen) is an analysis that measures the level of urea in milk.
By appropriately monitoring MUN levels in dairy cattle, you can strive to
balance protein and energy intake for lactating cows. With optimum protein
and energy balance, lactating cows can produce milk more cost effectively.
According to Phil Durst, Michigan State University Dairy Extension Agent,
"MUN testing should be considered one of the essential ways that cows
tell us about the ration they are eating. Are we getting the cow's
message? Not without MUN testing." Prior to Michigan State Extension,
Durst worked as a Pennsylvania Extension Agent and gained valuable experience
working with MUN testing for nearly three years.
Nutrition remains the largest single expense on a dairy operation. Utilizing
MUN testing to find how your ration rates makes good economic sense. Research
at Cornell University showed MUN testing could provide returns of 10 to
1. Besides adding to feed costs, excess protein is excreted as urinary nitrogen
that is highly unstable, creating an environmental concern. Ration adjustments
can result in minimizing negative impacts on the environment and help make
dairy producers better land stewards.
Upon an extensive review, NorthStar selected the Bentley Chemspec
150 instrument, a spectrophotometer, because of the machines high
level of accuracy. Although the Chemspec 150 analysis may be more expensive
than other less-accurate methods, it repeatedly out performs other MUN instruments,
with a standard deviation of less than 0.25, as compared to 1.50 or higher
for other methods. This accuracy gives you a more reliable test results
to base management decisions on.
Getting Started With MUN
Before starting MUN testing, it is highly recommended that you work with
a consultant/nutritionist. MUN levels should be viewed as a guide in making
management decisions. To begin with, establish your own MUN herd baseline
through monthly sampling with a minimum of at least two to three months.
Given the variability of MUN, the more cows tested the better, with group
or whole herd testing preferred. Individual cows or individual bulk tank
samples are not good representations of MUN as results can be too crude
and insensitive to assess protein feeding in herds. In addition, cows to
be tested need to be healthy and have free access to feed. MUN concentration
varies from morning to evening milk samples, therefore it is recommended
to always compare samples from the same milking, for example, compare morning
to morning samples.
Interpreting
Your MUN Results
Multiple studies have been done in attempt to find a "MUN herd average".
Researchers at the UW-Madison suggest a MUN herd average of 10-18 mg/dl
with a +/-3 mg/dl range from month to month. Once your individual herd baseline
has been established, nutritional management decisions can be made. High
and low levels of MUN should be considered based on your herd's baseline.
High MUN: This suggests there is an excess of protein in the
lactating cow's diet, indicating money is being spent on unused protein. Additionally,
some of the cow's energy is being used to remove the excess protein as waste,
when the cow's energy could have been spent for milk production. Therefore,
milk production is lower than potential levels. The effects of excess protein
include reduced reproductive efficiency, reduced milk production and/or
protein imbalance.
Low MUN: This suggests there is not enough crude or soluble protein
in the lactating cow's diet. Poor feed mixing, poor delivery of TMR, or
ration changes not accounted for by your nutritionist may also affect MUN.
The lack of protein in the diet often results in lower milk production,
lower milk protein and possible excessive weight gain.
Improve
Your Bottom-Line
MUN testing continues to grow as an important management tool for many dairy
producers to maximize efficiency of protein and energy utilization for lactating
cows. Through proper MUN monitoring nutrition can be improved. Proper nutrition
results in improved metabolic health, higher milk production levels, increased
reproductive performance, and lower feed costs, all of which affect your
bottom-line. Ask your DHI Technician about pricing or call 1.800.631.3510. |
|
|
