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7 times measuring moisture content of feeds pays off

Michelle Chang-Der Bedrosian
No matter how you measure the moisture content of your feeds, the most important things to remember are to take a representative sample and measure often.

At this time of the year, producers across the country are watching their Koster testers like hawks to make sure moisture levels are appropriate so they can hit the fields.  While most producers are concerned about moisture around harvest time, it can be beneficial, as well as profitable, to measure moisture content at these seven times throughout the year. 

1.  During harvest

Ensiling forages based on moisture content ensures the crop isn’t ensiled too wet (to avoid losses due to an unfortunate fermentation and seepage) or too dry (to avoid losses due to a stunted fermentation or spoilage).  Harvesting corn silage based on whole-plant moisture content ensures the starch is not overly mature or too available, allowing the cows to access the starch and make the most milk possible, while avoiding acidosis.

2.  Before mixing rations

I encourage producers to check the moisture content of their most widely used feeds (usually silages) on a daily basis.  When left unaccounted for, daily changes in moisture can cause over- and underfeeding of ingredients.  A diet is formulated to maximize productivity and minimize metabolic upsets, and diverging from the diet on paper negatively affects both.

3.  When feeding from a bag or tower silo

Due to how bunker silos and piles are filled, the stored forages are typically more stratified and, therefore, homogeneous.  In contrast, a bag silo is filled load-by-load, and moisture levels can change from day to day.  When feeding from a bag or tower silo, I encourage producers to monitor daily moisture levels.  Tower silos are more like bags than bunkers, but, because they tend to be filled with a “cone” pattern, they are somewhat stratified.

4.  After rain/snow events

Precipitation events can shift moisture levels by at least 3 percentage units.  If left unaccounted for, this can be expensive because of under- and overfeeding ingredients, but also because of lost production due to dietary variation impacts on the rumen.  Correcting these mistakes before they happen benefits everyone.

5.  When buying feed

If feed is priced on a dry matter (DM) basis, and DM is not monitored closely, this represents inevitable economic losses, which can add up very quickly.  Table 1 shows, on a 500-cow dairy, how improving DM analysis accuracy by just 1% can save $11,859 in feed costs over the course of a year.

Forage savings on a 500-cow dairy with a 1% improvement in dry matter (DM) analysis accuracy.

6.  Check wet feeds each time you get a load

Variation between loads of wet feed can be substantial.  Once all the loads have been received, collecting a representative sample, testing moisture content and correcting the diets is prudent.

7.  The “toes” (or ends) of bunkers/piles

DM levels of the feeds in these areas often differ from the majority of the silo. Make it a habit to check DM levels of feeds in these parts of the silo before feeding from them.

Moisture levels can be monitored in many ways. Laboratory measurements remain the gold standard.  Typical variation of laboratory results, compared to the actual moisture content of the feed, is roughly 1.5 percentage points either way.  This means if the actual moisture content of the forage is 70%, then the typical lab variation reported is 68.5% to 71.5%. 

Koster testers are widely used and most people are familiar with them.  However, they can be a fire hazard and can take up to an hour to get results.  A food dehydrator offers a more modern and safer alternative, but the drawback is it takes as long as eight to 12 hours to get results.  A faster method to measure DM is with an air fryer, which returns results within 30 minutes. 

The SCiO Cup was launched earlier this year as an easy way to analyze dry matter.

All of these methods return results within 2 percentage units of lab results, but the drawbacks are the time it takes to measure each sample and the various safety risks associated.  The SCiO™ Cup by Consumer Physics is a new portable DM analysis tool that returns results within 15 seconds.  Results are typically less than 2 percentage units different from the laboratory DM results.

No matter how you measure the moisture content of your feeds, the most important things to remember are to take a representative sample and measure often.  To learn more about measuring moisture content, or how to obtain a SCiO Cup, contact your local Vita Plus nutritionist.

Michelle Der Bedrosian

Dr. Michelle Chang-Der Bedrosian is forage products and dairy technical specialist for Vita Plus.