SILAGE MAKING
By Dr Jesse Kagai
To make silage, you need to have excess fodder during the season of feed abundance to be used in the season of feed scarcity. Silage making has a cost involved and can only be cost-effective if what is being preserved is in excess of what is being consumed by the animals.
The silage production process involves four stages, namely, forage harvesting, transport to the silo, compaction and silo sealing.
Before making silage, you need to know the amount of silage required (feed budget), which depends on the following factors:
- Number and type of livestock to be fed on the silage.
- Length of the feeding period (feed scarcity period).
- Percentage silage in the full ration.
- Material resources available (equipment, labour, finances, technical
- assistance, etc.).
To make good quality silage, the following basic principles have to be followed irrespective of the amount to be made.
- The material to be conserved must have a high nutritive value, harvest fodder at the right stage.
- The forage must not be contaminated with soil.
- The forage should be chopped into pieces no longer than 2 cm to facilitate good compaction and reduce air retention.
- It is necessary to expel the maximum amount of air within the forage before closing the silo preventing air and water penetration, this is achieved by good compaction.
- When using silage, the area exposed to air should be as small as possible and the time between opening and finishing the silo as short as possible.
The best system is to create silos that can be emptied over short periods, so the actual silo size depends on the amount of silage per animal and the number of animals to be fed from the
silo. For farmers with few animals, it is better to have several small silos than one big silo that takes a long period of time before being emptied during feed out.
The following are the advantages of using silage:
Drought reserve- silage is made from pasture or crop in times of plenty and stored for a long period. The silage is fed to animals only in times of extreme feed scarcity.
Increased productivity- where some fodder types are of high quality but only available at a particular time of the year, e.g. maize silage in dairy production systems.
Help in the management of fodder crops- silage making gives farmers the opportunity to harvest fodder at the right stage as opposed to cut and curry system where the fodder may overgrow thus losing the nutritive value. Harvesting the fodder for silage making also gives time for regrowth and thus increasing biomass production over time.
Ensiling process
The key to making silage is to create the right conditions for a good fermentation. Micro-organisms digest the sugars in the fodder and molasses to produce lactic acid, which acts as a natural preservative. This fermentation also makes the starch and fibres of the fodder easier for livestock to digest.
Harvest the fodder at the most nutritive stage; Napier at 4 feet high or maize at dough stage and wilt it to lose excess moisture.
Chop the fodder into small pieces (2-3 cm) by either hand, (but this requires a lot of labour) or a chopping machine. This is the best size for faster fermentation process and your cattle’s digestion.
If you do not have a chopper, then find one to rent when making silage.
The chopped fodder should not be left piled for long because it will heat up and this will increase the chance that everything will spoil.
Then prepare the silo which can either be tube silo or pit silo, depending on the amount of silage to be made and the materials available.
For fermentation to occur, the fodder must have enough fermentable sugars. For maize silage, the fodder already has enough of these sugars and therefore we do not need additives, however, for Napier grass silage, prepare molasses and water mixture at a ratio of 1:2.
Make silage in a space protected from potential disturbances. Make sure it is protected from direct sunlight and water as this will rot the silage, and from animals that may dig into your silage pile.
During compacting, add small layers of chopped fodder as you compact using bare feet and repeat this till you fill the silo while sprinkling the molasses mixture (for Napier grass silage) after each layer of fodder added. To reduce the risk of air pockets in the pile, compress the edges well. The more you compress it, the more air you push out of the pile to ensure a good fermentation.
When you have finished, make sure the silo is well sealed to avoid air getting into the silage. To keep the silo compressed, place a heavy object e.g. stone on top of the silage bag or soil on top of pit silage. Silage will be ready after 21 days but should only be opened for feeding when there is shortage of feed.
During feed out, it is normal that the top thin layer will be a little darker when opened due to residue air. Once the silage is ready for use, feed it continuously and close the silo after every feeding. Remove the silage in layers of smooth and even surfaces to avoid letting in air deep into the silo. Any silage that is too dark or rotten, do not feed it to any animals.
Like any new feed, it is always best to introduce the silage gradually, so the animals get used to the taste. It is best not to feed silage to animals under 6 months as their digestive systems are not fully developed. Silage is not easily digested by calves, so they will not benefit from its nutrition.
Dr Jesse Kagai is a scientist at International Livestock Research Institute
Email: J.Kagai@cgiar.org