Source: Manitoba Agriculture Food, and Rural Initiatives
The moisture content of silages and haylages can vary tremendously and should be checked weekly.
The amount of silage or haylage needed by dairy cows will change as its moisture content changes. For example, if your cow needs 60 lbs of silage containing 65% moisture, she needs 70 lbs of silage if the moisture increases to 70%, and 52 lbs of silage if the moisture drops to 60%. All three of these feeding scenarios provide exactly the same amount of forage dry matter.
Failure to adjust rations will mean feeding the cow either too much forage, thus lowering the energy density of the diet, or feeding the cow too little forage, thus lowering the fibre content of the ration making the cow susceptible to acidosis and milkfat depression.
Many computer programs, including the one used by Manitoba Agriculture, provide a printout showing the necessary ration adjustments as moisture content of the silage/haylage changes.
If the chief cook can live with the lingering aroma, the microwave provides a cheap and fast method of determining forage moisture levels. An accurate cooking or dieter’s scale is required. Use the following procedure:
- Weigh out 100 grams of representative sample and spread in a thin layer on a microwave safe dish.
- Put a glass of water in the back corner of the microwave to prevent damage.
- Place dish in microwave and heat for 2-3 minutes, re-weigh, mix and repeat until there is no change in weight. Reduce time of heating as the sample becomes drier.
- When repeat weights do not change, the sample is dry and this final weight can be used to calculate moisture content. If charring occurs, use the previous weight to calculate moisture content.
- Determine the dry matter content of the forage with the following formula:
Dry Weight Divided by Fresh Weight x 100 = % Dry Matter
To calculate moisture content, subtract % dry matter from 100.
For further information contact:
Farm Production Extension, Animal Nutritionist
Manitoba Agriculture Food, and Rural Initiatives
204-545 University Crescent
Winnipeg, MB R3T 5S6