Bale Silage - Frequently Asked Questions

What is bale silage?
The ensiling of high moisture green feed or hay bales in an enclosed airtight system. This allows preservation of feed with minimum nutrient and harvest losses.

At what moisture should you put up bale silage?
Bale silage should be put up at 45 – 55% moisture. If moisture is limited the material is susceptible to yeast and mold growth. Excess moisture can cause leaching as well as an extended fermentation period causing a larger loss of protein and energy.

How long do I have after baling to get them wrapped and sealed?
The sooner the bales are wrapped the better. The maximum time the bales should sit before wrapping is 12 hours. If too much time passes the bales will spoil rather than ferment.

What is actually happening in those white tubes?
Once the feed material is put into the silage bags or tubes and the system is sealed respiration of the plant consumes the oxygen present and burns some of the plant sugars. Carbon dioxide and heat is produced. Once all the oxygen is used, anaerobic bacteria begin to grow and fermentation begins. These bacteria produce lactic acid from the fermenting plant material which lowers the pH of the environment until all microbial growth ceases and fermentation is complete.

What happens if there is too much oxygen in the system?
If bales are not tight and the plastic not stretched and sealed, oxygen may continue to enter the system in which case respiration continues to occur and heat continues to be produced. If the temperature rises above 45 degrees Celsius heat damage occurs and protein is denatured and the damaged protein is unavailable to the animal.

How long should the system be left sealed before feeding?
It takes about 3 – 4 weeks for the pH to get low enough to stop all microbial growth. At this point the fermentation process is complete and it can be opened and fed.

What crops work the best for bale silage?

Legumes do not contain high amounts of water-soluble carbohydrates (WSC) and are difficult to ensile.
Legume / grass mixtures have higher sugar content and ferment better.
Cereals are easily ensiled because of their high WSC levels. Consider taking them early is you want to increase protein levels.
Do not try to ensile a feed that was meant for hay or Green feed and was then rained on. The WSC will have decreased and any dirt that splashes on the feed will cause unwanted molds.

What are the advantages of putting up bale silage?
The bale silage process allows you to harvest when your crop is of highest quality without waiting on the weather.
You will increase your dry matter yield/acre in this high moisture feed because of lower leaf loss and decreased transpiration as well as less sugar burn off that occurs during drying. You can use a wide range of crops in this process. You can utilize your haying equipment rather than investing or paying for silage harvesting. There are lower harvesting losses and feeding costs.

Sources of additional information:
How much silage do I have?
Bale silage
Making good silage
Heat damage in silage and hay
Bale silage knowledge nugget

Prepared by Ag-Info Centre, Alberta Agriculture and Forestry

For more information about the content of this document, contact Karin Lindquist.
This document is maintained by Mary Ann Nelson.
This information published to the web on September 3, 2003.
Last Reviewed/Revised on August 20, 2018.