Dr Jolly Kabirizi
Feed availability during the wet season often exceeds animal requirements. However, the accumulated fodder becomes rough and loses most of its nutritive value with maturity.
The excess fodder harvested at optimum nutritive value could be conserved as silage for dry season feeding when pasture is scarce so as to sustain milk production.
What is silage?
Silage is fermented, high-moisture and compacted fodder stored in airtight conditions, typically in a silo without first being dried and used as animal feed.
Silage is palatable to livestock and can be kept for up to three years without deteriorating.
Why silage not hay?
Forages can be made into hay to conserve the nutrients, especially protein before they decline in the plant. However, it is often too wet to dry them successfully.
Therefore, special machinery has to be used to assist the forage to dry quickly. Forage crops such as maize, are too thick-stemmed to dry successfully as hay.
What is a silo?
A structure of varying shapes and sizes could be an underground pit, portable cylindrical polythene bags and more made to store silage.
It is important that once the forage has been chopped, it is placed in the silos and compacted as much as possible to get the air out before the silo is sealed.
If too much air is present, the silage becomes too hot and the overheating causes the silage to become dark brown. Good silage has a sweet smell and is green to light brown in colour. It is important to pick a suitable location for the storage bags.
Stacking the bags carefully in a room can protect them against rats, mice and other pests. The surface area selected for storage of silage bags has a large impact on silage quality and ease of feeding from the bag.
A concrete floor provides an excellent surface for silage bags, easy removal of feed with little or no damage, can achieve exceptional drainage of water away from bags, discourages pests and makes inspection for damaged bags very easy.
When feeding cattle, silage should be used up to 25kg per day for 550kg animal and up to 5 kg for sheep and goats. To avoid off flavours in milk, silage should be fed to lactating cows after milking the animals.
Farmers are advised to start preparing for the dry season by conserving excess fodder.
Silage making process using a plastic bag
- Select a good strong plastic bag with high density (from fertiliser bags to shopping bags) with capacity from 5 to 50kg of fresh chopped green fodder. Imported plastic bags used in silage making are now available.
- Wilt the forage in the sun for about one hour to reduce the moisture content.
- Chop the forage into small pieces of about 1-3cm long before ensiling.
- It is important to time the cutting of the forage so that the cut forage is not sitting for more than a day waiting to be chopped and ensiled, otherwise it will become moldy or dry.
- Weigh the material.
- Add fermentable substrate at ensiling, for example molasses or maize bran. The addition of either molasses or maize bran is to act as a preservative. Molasses should be mixed with water at the ratio of one part of molasses with two parts of water to make it easier to apply.
Major materials used to make silage
- Pasture grasses like elephant grass (napier grass), Guinea grass, rhodes grass, brachiaria mulato and more mixed with pasture legumes such as lablab or fodder trees such as calian-dra. The legume component provides a source of protein.
- Crops such as maize and sorghum.
- Crop residues such as maize or sorghum stover, sweet potato vines and cassava leaves. When maize stover is ensiled with fresh grass, the product is “haylage”.