Why is silage important?
Fermentation is the process of converting grass sugars to acids, to preserve the nutritional value of silage by preventing spoilage and reducing any losses to the nutrients. Leaving you with a feed source that is palatable and has minimal nutritional losses when compared to the original crop. In order to maximise milk yields, dairy cows require a large amount of energy to maintain body condition, therefore high-quality silage is a great source of feed containing energy, protein and fibre to aid rumen health.
Once the clamp has been filled and sheeted, the nutritional value will remain stable until opened. The ensiling process has halted the breakdown of the crop as it has inhibited the entry of oxygen. Once the clamp is opened, the exposed areas of the clamp – i.e. the face, will begin degrading again as this is where losses begin & where value is lost.
How to avoid losses
Clamp losses can be split into two categories, those seen when ensiling the crop & those seen once the clamp is opened. Losses can be minimised through the clamp design – a narrower face is better as this minimises the amount of crop exposed to the air once opened, the face size should be determined by the speed of emptying and should ideally move back 2m a week. The type of walls can also influence losses, sloping wall clamps improve compaction against the panels.
Compaction is key to ensiling, as this ensures air pockets are removed, thus preventing aerobic bacteria and creates the anaerobic conditions needed for fermentation. It has been proven that the better the compaction, the lower the losses due to poor fermentation – a well compacted clamp face is easier to cut out & more stable as oxygen cannot penetrate as easily.
Using an oxygen barrier silage sheet will also help with reducing clamp losses, as when compared to conventional plastic sheeting typically 50% of Dry Matter is lost in the top 1m of the clamp. By stopping the entry of oxygen into the clamp, the fermentation process begins sooner, DM is retained in that top metre, and spoilage is inhibited.
Removal of silage from the face
Good clamp management once opened is key to reducing losses. Keeping waste silage, muck, and slurry away from the face is the easiest way to avoid losses, along with maintaining a clean face. Use of a block cutter causes minimum disturbance to the face & leaves it neat and tight, which inhibits oxygen penetration. A shear grab is also an effective option but will cause more disturbance and will lead to lose silage falling down, which as mentioned before should be cleaned up and fed immediately. Perhaps the least effective way in removing silage from the face is by use of a bucket as this causes a loose & cracked face, it also injects oxygen further into the clamp when loosening the face which can cause spoilage further back into the clamp under the sheet. DM losses vary and with poor compaction, sealing and where the face has been loosened can be up to 15% when compared with as little as 1% with a well sealed, well compacted clamp.