07/09/2025
Centre for Yubja Conservation and Development, Sertsam, Jarey, Lhuentse
Napier Silage Making:
Napier grass (Pennisetum purpureum), also known as Elephant grass, is a high-yielding, perennial tropical grass widely used as fodder for livestock. Making silage from Napier grass is an excellent way to preserve its nutritional value for use during dry seasons when fresh forage is scarce.
Silage is produced through a process called anaerobic fermentation, where lactic acid bacteria convert soluble carbohydrates in the plant into organic acids (primarily lactic acid). This drop in pH preserves the forage in a succulent state.
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Why Make Napier Grass Silage?
1. Preservation: Stores excess forage for up to 1-2 years without significant nutrient loss.
2. Dry Season Feeding: Ensures a consistent, high-quality feed supply during droughts or winter.
3. Reduces Waste: Utilizes surplus grass that might otherwise be wasted.
4. High Nutrition: Well-made silage retains up to 85% of the original feed value of the fresh grass.
5. Palatable: Animals generally find good-quality silage very tasty.
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Step-by-Step Process of Making Napier Silage
Step 1: Harvesting at the Right Stage
This is the most critical factor for success.
· Optimal Time: Harvest Napier grass at the pre-flowering or early flowering stage. This is typically when the plant is about 1 to 1.5 meters (3-5 feet) tall.
· Why? At this stage, the plant has the highest balance of nutrients (energy and protein) and moisture content (ideal is 65-70%). If too mature, the grass becomes fibrous and low in sugar, making fermentation difficult.
· Weather: Harvest on a sunny day. Avoid harvesting immediately after rain, as excess moisture will dilute sugars and lead to poor fermentation.
Step 2: Wilting (Optional but Highly Recommended)
· After cutting, allow the grass to wilt in the sun for 4 to 6 hours.
· Goal: To reduce the moisture content to the ideal range of 60-70%. Grass that is too wet leaches nutrients and can cause clostridial fermentation (bad silage).
· Test: A simple test is to tightly wring a handful of wilted grass. If you get only a few drops of water, the moisture is perfect. If water streams out, it's too wet and needs more wilting.
Step 3: Chopping
· Chop the wilted grass into short pieces (1-2 inches or 2-5 cm long) using a chaff cutter or a silage chopper.
· Benefits of Chopping:
· Easier to pack and compress, removing more air.
· Increases the surface area for bacteria to work.
· Makes it easier for animals to eat and digest.
· Reduces wastage.
Step 4: Additives (Optional for Enhanced Quality)
While not always necessary, additives can significantly improve fermentation, especially if the grass is too dry or mature.
· Molasses: The most common additive. Dilute 1 part molasses in 3 parts water and sprinkle evenly over the chopped grass (at a rate of 20-40 kg per ton of forage). It provides extra sugars for the bacteria, ensuring a rapid pH drop.
· Legumes: Mixing with high-protein legumes like Lucerne or Desmodium can boost the protein content of the silage.
· Commercial Inoculants: These are packets of specific lactic acid bacteria that you mix with water and spray onto the forage. They ensure a fast and efficient fermentation process.
· Salt: A small amount of common salt (0.5%) can be added to improve taste and slightly inhibit undesirable bacteria.
Step 5: Packing and Sealing (The Key to Anaerobic Conditions)
· Pit Method: This is the most common and effective method.
1. Dig a trench silo (pit) in a well-drained area. The sides should be sloped.
2. Line the pit with a plastic sheet (optional but recommended to prevent seepage).
3. Start filling the pit with the chopped grass in layers of 6-8 inches.
4. Compact each layer thoroughly. This is vital! Use a tractor, a heavy vehicle, or laborers with tramping boots to remove as much air as possible. Inadequate packing is a leading cause of silage failure.
· Stack Method: For smaller quantities, you can create a stack on a concrete floor or a high, dry area. The principles of chopping, adding molasses, and compacting remain the same.
· Sealing:
1. Once the pile is built (slightly dome-shaped to shed water), cover it completely with a thick, airtight plastic sheet (silage film).
2. Ensure the edges are properly sealed by burying them in soil or placing heavy weights (old tires, sandbags, timber) around the perimeter.
3. The seal must be airtight to prevent oxygen from entering and spoiling the silage.
Step 6: Storage and Unloading
· Leave the silage to ferment undisturbed for at least 6-8 weeks.
· After opening the pit, feed the silage to livestock within a few days to a week to avoid spoilage from exposure to air.
· Feed from one face of the pit, moving systematically across to minimize the surface area exposed to air.
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Feeding Napier Silage
· Introduce slowly: Allow animals 3-5 days to adapt to the new feed.
· Do not feed moldy silage: It can make animals sick.
· Balance the ration: Silage is a good roughage but may need to be supplemented with concentrates (e.g., dairy meal) for high-producing animals like dairy cows.
By following these steps carefully, you can produce high-quality Napier grass silage that will keep your livestock healthy and productive throughout the year.
