How to Make Silage

Feeding of farm animal is a major task in animal production, animals have to be fed to be productive. Not just feeding with any feed but feeding the right quality and quantity of feed with the required nutrients. Several approaches have been initiated to help increase feed availability for farm animals during the scarcity of green forage, such as, hay making, silage and the rest. I will be sharing how to make a silage for the farm animals.

Silage is a moist forage that is produced from the acidic fermentation of green forage crops that have been compressed and stored under anaerobic conditions in a storage system called silo. The process of making silage involves fermentation under anaerobic conditions. It prevents fresh fodder from decomposing and allows it to keep its nutrient quality.

Silage making steps

Once the fresh forage have been harvested, chopped, compacted and well sealed, the Silage is then prepared in these four phases, namely:

1. Aerobic phase

2. Fermentation phase

3. Stable phase

4. Feed out phase or aerobic spoilage phase

Phase one: Aerobic phase

In this phase, oxygen trapped between the forage particles is eliminated as a result of the respiration of the plant material and the aerobic activities of yeast and bacteria. The plant enzymes are also active during this phase provided the pH is still within the normal range for fresh material (6.0-6.5). This phase may take a few hours only provided the forage is well compacted and sealed as soon as possible after harvesting. The following processes are carried out to achieve the phase one:

• After harvesting, the forage materials are chopped as short as possible.

• After chopping the materials, they are deposited into the storage container and compacted tightly such that a finger will not be able to penetrate when inserted.

• The storage container should be sealed airtight.

Phase two: Fermentation phase

This stage begins once the oxygen is gone and the storage becomes anaerobic. Depending on the properties of the ensiled crop and the ensiling  conditions, this phase may last several days to weeks. A successful fermentation will see the number of lactic acid producing bacteria dominate, reducing the pH to 3.5 to 4.5. The lower pH level may be achieved in unwilted forage whereas the higher level are from wilted forage. Adding molasses to the fodder is recommended since it is rich in sugar, which enables the bacteria to produce the organic acids immediately. The more molasses you add, the faster the fermentation and preservation process will occur.

Phase 3: Stable phase

Once the pH level has dropped and air and water are not permitted to enter the storage containers, most micro organisms of phase2 slowly decreases in number, resulting in a silage with is relatively stable. However, some acids tolerant microorganisms like Clostrida and Bacilli survive this period in almost inactive state, usually as spores. 

 This phase can be attained by:

• Maintaining an air tight seal around the silage

• Repair holes as soon as they are noticed.

Phase four: Feed Out phase or Aerobic spoilage phase.

This silage making process starts when holes are made in the storage container or site by mice, birds or other agents. This stage occurs in two stages:

• Degradation of the preserving organic acid by yeasts and occasionally acetic and bacteria. This results in the rise in the pH and then the second stage begins.

• This is associated with increasing temperature in the silage and activities by spoilage micro organisms such as Baccili, moulds and enterobacteria.

The spoilage rate is highly dependent on the numbers and activities of spoilage organisms in the silage. This is achieved through the following processes:

• Maintaining an airtight seal.

• Feed out to ensure about 20-30cm removal from the entire silage each day.

• If the silage gets hot, feed it out at a faster rate.

It takes about 30 to 40 days for the silage to mature and be ready for feeding. Never open the whole silage container at once, only one end of the narrow side should be opened a bit. Remove enough material for each day’s feeding and cover again. This way air is prevented from entering the silage.

However, once the container is opened, use the silage as quickly as possible.

Silage quality

Silage can be classified as good quality depending on its physical characteristics like taste, smell, and colour but more precisely by measuring the pH in the container.

A pH of 3.5 to 4.2 indicates excellent fresh acidic/sweetish silage, 4.2 to 4.5 for good acidic, 4.5 to 5.0 fair less acidic and above 5.0 for poor pungent/rancid smelling silage.

Good silage should be light greenish or greenish brown or golden in colour. It should have a pleasant smell like that of vinegar, and acidic in taste, and should not contain mould.

Black indicates poor silage. Overheated silage has the smell of burnt sugar and dry in texture. Badly fermented silage has offensive taste, strong smell, slimy soft texture when rubbed from the fibre or leaf.