Step by step guide to silage making for your Dairy cattles


Silage and hay are preserved feeds that come in handy for dairy cows during periods of scarcity of green forage.

The process of making silage involves fermentation under anaerobic conditions. It prevents fresh fodder from decomposing and allows it to keep its nutrient quality.

It requires sufficient soluble carbohydrates (sugars) for organic acid production. 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 acidification and preservation process will occur.







Silage is preserved pasture!

It is an important way farmers use to feed cows, goats and sheep during periods when pasture isn’t good, such as dry seasons.

* Silage assists farmers store forage (pasture) for upto 2yrs while maintaining their full nutrients.

Napier grass, sorghum, surplus maize and sugar cane tops can all be stored as silage. Prepare silage from excess forage when it is still green and of good quality, and during a dry spell.


Tower silos

Tower silos are good for making silage because of their elevated heights, which aids compaction and air exclusion.

However, their major disadvantages are high cost of construction and need for specialised machinery to propel silage material over high elevations.

Heap or stack silos

Apart from the polythene sheet cover, no structure is necessary to conserve silage in this silo.

The silage is simply placed on a convenient patch of ground with continuous compaction up to a height of about 2-4m and sealed in a day, or a maximum of three days.

The area round the heap must be drained. Heap silos are cheap to construct and for this reason, they are very popular with many Kenyan farmers.

However, sometimes silage along the sides may get spoilt due to improper compaction.

Trench or pit silos

Trench silos are constructed by excavating soil to form a trench or a furrow on a slightly sloppy ground, meaning the silage material will be ensiled below the ground surface.

It enables easy compaction of the material being conserved.

The width should be at least 2m wide to allow compaction and the walls should be slightly slanting inwards towards the floor.

Major limitations include the process is labour intensive and silage may spoil due to rain water seepage.

Polytube or bag silos

A polytube for silage making is a seamless 1,000 micron gauge open ended bag ranging between 2-2.5m long.

It is tied on one end, filled with the material being ensiled and then tied at the top for fermentation to take place.

It should be stored away from direct sunlight with some weights placed at the top. A single bag silo can hold between 350 to 500kg of silage and is suitable for small-scale farmers.

The main limitation of this type of silo is destruction by rodents and high labour requirements in the long run.

Bunker or walled-surface silos

Bunker silos are used in flat areas unsuitable for trench silos. Above-ground walls are constructed using concrete or timber braced with poles.

Timber walls that come into contact with silage should not be treated with preservatives but should be covered with polythene sheets to prevent moisture and acid penetration.

Concrete floors are usually needed for easier loading and to minimise feed waste. Bunker silos require adequate drainage.

They are suited for medium and large scale farmers.


Why feed your cows on silage?

Silage ensures high milk production and healthy dairy animals, especially during dry seasons. It is palatable, laxative, digestible, nutritious and requires less floor area for storage than hay.


Silage preparation

Silage is produced through use of pits or trenches, towers and sacks for small quantities. However, pits are mostly used to prepare silage for large dairy units.

The silage pit should be located at a place safe from rodents, away from direct sunlight and with higher elevation or slightly sloppy to avoid rain water entering into the facility.

The ideal materials used in silage making should have a moisture content of 60 to 70 per cent or dry matter in the range of 30 to 35 per cent (tested by taking a small bundle of the fodder and wringing with two hands and if no moisture comes out, it is ready to ensile) and a pH below 4.2 for wet forage and below 4.8 for wilted forage. In rainy periods when the fodder is too wet, containing more than 70 per cent water, it is advisable to wilt it in the sun first.

Crops such as maize, sorghum, oats, pearl millet, and napier grass are very suitable for ensiling (preserve green fodder).

They contain fermentable carbohydrates (sugar) necessary for bacteria to produce sufficient organic acid that acts as a preservative.

Though leguminous fodders can also be used, they are rich in proteins and low in sugars making them a bit difficult to ensile.

Harvesting maize or sorghum for making silage is ideal when their seeds are soft but not milky when squeezed open.

Napier grass, on the other hand, needs to be about a metre high while legumes should have young pods, which are not dry.

Apart from molasses, other additives like common salt, formic acid, lime or urea can also be used to enable good fermentation process.

To start, prepare the pit and then place a big polythene sheet on the floor and walls. Cover about a metre of walls so that the forage does not come into contact with soil.

Chop the fresh forage to lengths of about one inch using either a panga or a chaff cutter. Prepare the first layer by emptying the chopped materials into the plastic lined pit to approximately 15cm high, and spread evenly.

Fungi growth

Then dilute molasses with water at a ratio of about 1:2 and sprinkle evenly over the forage layer using a garden water sprayer.

Compact the layer by trampling on it using clean boots to force out as much air as possible. This will prevent fungi growth and spoilage.

Repeat this process of adding bags of chopped forage, diluted molasses while compacting to expel maximum air out of the material until the pit gets filled in a doom shape.

After the final filling and compacting, wrap the polythene sheet around the silage and cover the top of the heap with a second sheet to prevent water from running into the silage.

Finally cover the heap with a thick layer of soil of at least 2ft giving special attention to the edges first as you come towards the middle to keep the air out and to prevent damage of the polythene by rain, birds and rodents.

With good sheeting and enough soil on it, the silage can be kept for more than one year.

Opening the silage pit

It takes about 30 to 40 days for the silage to mature and be ready for feeding. Never open the whole silage pit 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 pit 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 pit.

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.

Feeding cows with silage

A dairy cow is fed depending on the body weight or generally be given about 6kg to 15kg of silage per day. It is advisable not to feed silage immediately before or during milking especially when the quality is poor as the milk can easily take the smell of the feeds. During these times, a cow can be fed fresh grass, hay, legumes and concentrates.

After feeding silage, the bunks and corners of the feeding troughs should be cleaned immediately to prevent contamination.


Step 1.

Prepare a shallow pit, preferably on slightly sloping ground. The depth of the pit should decrease from the higher side of the sloping ground to the lower side giving a wedge-like shape. Dimensions of the pit depend on the amount of forage to be stored.

As a rule of thumb 72 cubic feet (2 cubic metres) holds 1000 kg (or 20 bags) of fresh, chopped material. This requires 2030 litres of molasses and 10 metres of polythene sheeting.

Step 2.

Chop the forage to be ensiled to lengths of about 1 inch tong using either a panga or a chaff cutter.

Step 3.

Spread polythene sheets over the sides and floor of the pit so that the forage does not come into contact with soil.

Step 4.

Empty 1 bag of about 50 kg of chopped material into the plastic lined pit and spread into a thin layer. Repeat this till the pit is filled to 1/3 (6 bags).

Step 5.

Dilute 1 litre of molasses ((hat is about 1 kg Kasuku tin full) with 3 litres (3 Kasuku tins) of water. Sprinkle this mixture over the layer of chopped forage. Use a garden sprayer to distribute the solution evenly.

This helps to feed the micro-organisms to make, the silage acid quickly, which will prevent rotting.

Step 6.

Press the forage down with your feet or a suitable weight (e.g. a drum full of water) to force out as much air as possible. This will prevent fungi attacking and destroying the forage.

Step 7.

Add another bag of the chopped feed, sprinkle diluted molasses and compact the forage again. Repeat this process of adding forage, diluted molasses and compacting until the pit filled in a doom shape.

Step 8.

Cover the pit after a final pressing with polythene sheeting to prevent water seeping into the silage and dig a small trench around the sides of the pit.

Step 9.

Then, cover the pit with soil: a layer of 24 inches (in the case of wet, fresh fodder) up to 36 inches (in the case of more dry forage) of soil to keep the air out and to prevent damage of the polythene by rain, birds and rodents.

Step 10.

The conservation of the material by microorganisms takes a couple of weeks. Thereafter, it can be fed, but you better leave it until a time of feed shortage. With good sheeting and enough soil on it, the silage can be kept well for 1 – 2 years.

Step 11.

Open the pit from the lower side of the slope. Remove enough material for one day’s feeding, and then cover the open end again.



  • A grade cow may eat up to 30 kg of silage per day.
  • To ensure that the milk has no silage smell, feed after milking or at least 3 hours before milking.



  • A store of feed for the dry season.
  • Animals remain in good condition.
  • More milk at a better price.
  • Thus more income in the dry season.

Source :

Step by step guide to silage making for more milk during dry season

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