During the bale silaging process, farmers put high-moisture green feed or hay bales into airtight plastic enclosures. This preserves the feed through fermentation, with minimal nutrient and harvest loss.
Bale silage should be wrapped at 45 to 55% moisture.
If moisture is too low, the material is susceptible to yeast and mould growth.
Excess moisture can result in leaching and an extended fermentation period, causing a greater loss of protein and energy. For more information, see Bale moisture.
The maximum time the bales should sit before wrapping is 12 hours. If too much time passes, the bales will spoil rather than ferment.
Ensiling process steps
- Feed material is individually wrapped, or put into silage bags or tubes.
- Bags or tubes are sealed.
- Plant respiration consumes the oxygen present and burns some of the plant sugars. Carbon dioxide and heat are produced.
- Once all the oxygen is used, anaerobic bacteria start growing and fermentation begins.
- These bacteria produce lactic acid from the fermenting plant material. This lowers the pH of the environment until all microbial growth stops.
- It takes about 3 to 4 weeks for the pH to get low enough to stop all microbial growth. At this point, the fermentation process is complete. The bale can be opened and the feed can be used.
If bales are not tight and the plastic is not stretched and sealed properly, oxygen may continue to enter the system. If that happens, respiration will go on and heat will continue to be produced.
If the temperature rises above 45 degrees C, the heat produced damages protein. The damaged protein in the feed will be unavailable to the animals.
Choosing the right crops
A wide range of crops can be used for bale silage. However, some make better silage than others. Good choices include:
- legume/grass mixtures, which have desirable water soluble carbohydrate (WSC) levels
- annual crops such as cereals, due to their high WSC levels
Consider harvesting cereals early to increase protein levels.
Poor choices for silage include:
- legumes, which contain lower WSC levels
- hay or green feed that was rained on (the WSC will have decreased and any dirt that splashes on the feed will cause unwanted mould)
Advantages of bale silage
The bale silage process allows for harvesting when the crop is at its highest quality without waiting on the weather.
Dry-matter yield per acre in this high-moisture feed will increase through:
- lower leaf loss
- decreased plant transpiration
- reduced sugar burn off that occurs during drying
Haying equipment can be used rather than investing in or paying for silage harvesting. This results in fewer harvesting losses and lower feeding costs.