Technique for Dry Matter Analysis of Feedstuffs.
The following technique describes how a microwave oven can be used to determine moisture content in feedstuffs in a matter of minutes with the accuracy close to that obtained when using accepted research methods.
All that is needed is:
• an electronic scale that can weight with an accuracy of 0,01 grams ,
• a piece of paper (quarter A4 per examination),
• a microwave oven.
The accuracy of the results is dependent upon the quality of scale used.
The procedure for determination of moisture (dry matter) content with the microwave oven is as follows:
1. Place a piece of paper (quarter A4) on the scale and set the scales to 0.(‘tare’ with the paper on the scales)
2. Take the paper from the scales and spread a small quantity of the feedstuff evenly on the paper. An amount between 5 and 15 grams is enough. Spread the feedstuff out for easy drying.
3. Put the paper + feedstuff on the scales. Write down the weight on a piece of paper.
4. Next put the paper + feedstuff in the micro-wave. Set the micro-wave at 450 watts. Heat the sample for 3 minutes.
5. Next weigh the paper + feedstuff on the scales. Write down the weight underneath the initial weight.
Repeat as in step 4 but only heat the sample for 1 minute.
6. Repeat step 5 until the weight reduction is less than 0,05 grams.
Make sure not to burn the sample!!!. If a burning smell comes from the micro-wave during heating or if burned, blackfeedstuff is noticeable in the sample, stop the micro-wave immediately, weigh the sample and record the weight as the final weight.
7. Calculate the dry matter of the forage in the following way:
Dry matter percentage of the sample= (Weight of the sample after drying/ Weight of the sample before drying) x 100%
On a calculator:
• Type: the weight of the sample after drying (the lowest weight)
• Press: /
• Type: the weight of the sample before drying (the highest weight)
• Press: %
• Read the dry matter % of the sample in the display.