Making good silage is not easy. However, the following tips can help to improve your silage quality:
Whole-plant maize silage in dairy cattle feeding rations is preferred not only because of its natural high-energy value and good supply of fibre, but also because the whole plant is harvested, maximizing the yield. It also has up to 50 per cent more energy than dried maize kernels.
How to ensile
Napier grass, maize, sorghum, and sugarcane are the most commonly used forages. However, other products such as pineapple waste, briachiara grass, and so on, can also work.
The container used to make silage can be a trench, a pit, a drum or empty fertiliser bags with polythene linings, polythene tubes and plastic shopping bags. The container is called a silo.
Step 1: Build the silo before the end of the green season, when there is still plenty of green fodder available. The pit silo should be located on high ground so that no water will run into it when it rains. The pit should be smaller at the bottom than at the top, so taper in the sides a little. This will make the structure stronger.
Step 2: Cut the crop just before flowering, as the protein content is high just before that stage. Leave the freshly cut fodder to dry in the sun for two to three hours, then chop the green fodder into small pieces about 1 to 2cm in size.
Step 3: Place plastic sheeting on the bottom and on the sides to prevent the fodder from touching the soil. Seal the pit to prevent air and water from getting in.
Step 4: Place the chopped material into the plastic-lined pit. Spread uniformly into layers of 30cm thick and compact each time by using a suitable weight to expel air. Over the top of each layer you should spread evenly a handful of salt and some molasses (for 1,000kg of green material you need 15-20kg molasses). Molasses is a thick syrup produced as a by-product in sugar making. It provides readily available energy and minerals.
Step 5: When the pit is full, add some paddy straw and cover it with a plastic sheet or some gunny sacks. Finally, you should cover the whole pile with a thick layer of mud to prevent air and water from getting in. The material is ready for use in about three weeks. The silage, if properly made, should be ready for use in 90 days. Good silage smells fresh and fruity and is light yellow brown or green. If the silage smells rotten and is black and slimy, then it is not good for your cow’s consumption. If this happens, it means that something went wrong and the silage should not be fed to the animals. After the pit has been opened, keep it covered with gunnysacks or a plastic sheet to keep the silage in good condition.
For plastic silos:
- Harvested fodder is chopped into 1” lengths, mixed with molasses diluted in water (1:2);
- The mixture is then packed into a polythene tubing;
- When the tube is filled, both ends are tightly tied; and
- The bag is then placed in an airtight container for the fermentation to occur.
The advantage of plastic silos is that they are low cost and can be moved easily. The quality of silage obtained, with maximised nutrient preservation, depends on the quality of the fodder used, the ensiling and use of molasses. For example, Napier grass should be ensiled when a metre in length (101 days after planting). Properly ensiled material can store up to one year without losing quality.
Bad silage can cause diseases in your animals that can sometimes lead to death.
Tips to help you produce high quality silage:
- Moisture levels of the crop used
One of the most critical factors affecting fermentation is the moisture in the crop at the time of ensiling.
A drier plant will not permit air to be excluded from the silos, leading to aerobic fermentation of undesired bacteria and yeasts;
Plants with excess moisture levels will lead to clostridia fermentation, rotting and production of smelly compounds. Thus, controlling silage moisture at harvest is the key to complete air exclusion that allows lactic acid producing bacteria to begin the desirable fermentation.
You can try yourself by making a fodder ball. If the fodder ball falls apart quickly, it means it is too dry and you must add a bit of water to the fodder before putting it in the pit. If the ball falls apart slowly and there is no water left in your hand, then it is ready to put in the silo.
- Proper management
Because making silage is anaerobic, rapid and effective filling and sealing of the silo is critical. Minimise the air that gets into the silo. How this is done will depend on the type of silo used.
Minimise disturbance to the silage face (the part of the silage that is outermost) to prevent air from getting into it.
Silage cutters (also known as shear grabs or block cutters) are an excellent tool for reducing waste at feed-out. They should be well maintained to ensure they cut and don’t tear.
Keeping the silage faces clean and free of spoilage is also essential. These can become reservoirs of heat and spoilage organisms if left close to the silo.
Plastic sheeting/film is normally used to seal horizontal silos. This plastic should be removed only as the silage is used.
- Harvesting mature corn
Harvest maize that is mature but not dry, as it has enough sugars for proper fermentation. Lactic acid bacteria cannot break down starch, but rather need simple sugars. Immature kernels have only starch.
Energy, nutrient yield, and silage quality are maximised when the plant reaches maturity. This is when the kernels start to develop the “black layer” at their bases. Harvest time will differ depending on the maize variety and the field conditions. It is important to not only depend on generic instructions from the seed supplier, but also to consult an agronomist, especially when changing maize varieties.
- Using additives
Additives enhance silage quality above what can be achieved by sound silage management methods. Adding molasses, for example, improves lactic acid fermentation. Lactic acid bacteria consume energy compounds, that is sugars. Thus, before they die off when the pH reaches 4, they continuously reduce the energy content of your silage. To prevent that, add other acids such as propionic acid, which reduces yeast and mould growth in silage.
If the silage quality remains low despite all of the above, then other additives can be applied.
Urea is an inexpensive source of readily available nitrogen. Adding urea to corn silage improves its protein content, enabling lactic acid bacteria to grow and thrive. This is not a sure measure to improve silage quality, but certainly one that is used frequently in the field.
Additives should not replace the basic principles of silage preparation. Not following these principles is likely to lead to the search for additives to repair the otherwise avoidable damage.
It is advisable that you make smaller silos rather than one big one. This will keep the unused silage untouched as you open the silos you intend to use.
Feeding livestock using silage
- A grade cow may eat up to 40kg of silage per day. Supplement lactating cows with dairy meal at the rate of 1kg of dairy meal for every extra 1.5kg of milk produced above eight litres. To avoid bad flavours in milk, feed silage after morning milking and at least three hours before afternoon milking.
- Do not feed calves below six months with silage. This is because the rumen in small calves is not yet well-developed, thus, they do not have enough microbes in the stomach to digest silage. Feeding such calves with silage will cause them to have ‘distended stomachs’, which in the long run, adversely affects their growth. Instead, feed them on hay, milk, water, pellets, or dairy meal. Introduce all the products from the first day of birth to allow your calf to interact and get used to them.