The aim should always be to produce silage that will be containing the highest possible metabolizable energy (ME, MJ/kgDM) and crude protein (CP%) contents. The forage crops for silage comprise:

1.       Whole grain cereals such as Maize

Whole crop maize is not difficult to ensile as it has high levels of water soluble carbohydrates (10 to 12% of DM), low levels of crude protein (7 to 9% of DM), but high levels of lactic acid (5 to 8%). The pH of maize silage drops to below 4.0 within 48 hr after ensiling. Whole crop maize should be ensiled when the DM content of the whole plant is 30 to 35%. At this growth stage the bottom leaves of maize plants start to become dry while the kernels on the maize cobs are in the ½ to ¾ milk stage. Maize is often ensiled too early resulting in silage containing a lower starch content, lower energy value and low DM content as well as a reduced DM yield. Ensiling maize at 25% DM results in a 10% yield reduction as well as a less favourable fermentation and less palatable silage. The optimal chop length of maize silage should be 8 to 12 mm. Good maize silage should have an energy value of 10.5 MJ ME/kg DM (total digestible nutrient content of 70%), crude protein (CP) content of 8 to 9%, neutral detergent fibre (NDF) content of 40 to 45%, and a starch content of 25 to 30% on a DM basis.

2.       Small grain cereals such as forage sorghum

Cereal crops, such as forage sorghum, oats, wheat, etc, that are small seeded, should be harvested at the soft dough stage.

Forage sorghum variety at KALRO FCRC Alupe

Whole sorghum crop cereal has only 5 to 8% water soluble carbohydrates at the soft dough stage which may be limiting. An efficient lactic acid bacteria (LAB) inoculant or Molasses can be applied when ensiling whole crop small grain to ensure efficient utilization of the water soluble carbohydrates intensive production of lactic acid and a rapid drop in pH to improve the preservation or anaerobic fermentation efficiency.

3.       Sweet potato vines and roots silage

Sweet potato normally has a high risk of spoilage due to its high water content. However, there are special methods for creating sweet potato silage that allow for the preservation of the vines and roots within a silo. The comprise the internal drainage system for the plastic tube silo, fitted with a tap to control flow of effluent and a compacting drum.

The internal drainage system for sweet potato tube silage

The compacting drum for the tube silage

Well-made sweet potato silage can provide nutritious feed for dairy cattle. Sweet potato silage consists of chopped, fermented vines and roots. The chopped vines and roots should be combined in a ratio of up to 30% roots or a grass like Napier. A ferment starter, like molasses, is then added to aid the process of fermentation and increase nutrient content. The keys to preserving sweet potato silage are making sure that it is not exposed to air and that excess water does not accumulate in the bottom of the container. To accomplish this, you will need to construct a special type of plastic tube silo. One of these silos should hold up to 500-1000 kg of chopped, well compacted silage, depending tube or silo type.

Sweetpotato vines mixed with maize bran after wilting

Adding weight (stones) to the compacted silage for preservation

Controlling effluent from the tube silage to avoid rotting

Well-prepared sweet potato silage is bright or light yellow-green in color, has a strong smell similar to that of fermented milk and a firm texture. Poor quality silage tends to smell similar to rancid butter or ammonia. Sweet potato tube silage should be stored under shade, for example in a store. Rodents like rats that could tear the tube need to be controlled. When feeding, open the tube and after removing the amount needed, remember to re-tie without trapping air inside.

Well preserved sweetpotato tube silage

4.       Fodder forages like Napier grass silage

The first cut of fodder forages like Napier grass, Stylosanthes, Brachiaria, Pannicum and other green fodders will be very wet as it is young plant material. The chopped material can be left to wilt in the sun for a few hours (less than five hours) before ensiling. If it can only be cut in the afternoon, it can be left overnight, and then ensiled by mid-morning the next day. It is best to use an inoculant, like molasses, cereal bran, or in combination with forage sorghum water soluble carbohydrates, to assist in fermentation. The next cut of Napier grass may still be very wet, depending on the rains, when it is ready for harvesting.

Youth compacting trench silo Napier grass silage with a drum

A dry matter test is necessary, and if the plant material is too wet, it should be cut and wilted in the same way as the early cut. If possible, clear weather should be chosen for harvesting, especially with Napier grass. Any plant material should not be left any longer than a few hours in the sun, overnight or in the rain for wilting because it will start to go mouldy and loose its nutrients.

To make good quality silage, irrespective of the amount of silage to be made, the following requirements and principles must be applied:

·         The available silo capacity must be adequate for the amount of material (herbage) to be ensiled and rate of silo filling in accordance with compaction capability

·         Air must be completely excluded from the ensiled material to limit growth of yeasts and moulds within the ensiled material,

·         A sufficient amount of sugars or water soluble carbohydrates (WSC), must be available as energy source for bacteria during the anaerobic fermentation process; and

·         The plant material (herbage) must contain a high number of efficient lactic acid bacteria to convert sugars to lactic acid which preserves the plant material as good silage. This ensures a rapid drop in pH to below 4.0, thus preventing growth of harmful bacteria (that causes spoilage) and thereby ensuring preservation of the silage.

The amount of silage required, and therefore the size of the silo, depends on the following factors:

·         The number of dairy cattle to feed, length of feeding period and Amount of silage to be included in the feed ration of dairy cattle, usually 50-70% in total mixed ration (TMR)

·         This can be illustrated by the following example, where an adult dairy cow, consuming 50% of the ration in the form of silage would receive 5 kg of (DM) per day. For a feeding period of 180 days, 900 kg of DM/cow would be required; that is, 3.6 tons of fresh forage, containing 25% DM. Considering 15% silage loss 540 kg of fresh forage should be added, to arrive at a total of 4.14 tons per head. This is equivalent to 2.3 m³ of silo capacity per animal, assuming a density of 0.6 t/m3. This calculation can also be carried out in reverse, taking into account the resources available on the farm, amount to be conserved and the type and capacity of the silo.

·         Effluent losses of 2–10% that occur from respiration during wilting and moisture seepage contain soluble and highly digestible nutrients; seepage should be avoided by wilting the herbage and good choice of silo type for ensiling.

·         Dry matter yield of common fodders used for silage making is 4–12 t/acre for Napier grass, 6.8–8.8 t/acre for sorghum E6518 and 9.6 t/acre for maize. 25 to 30-kilogram silage can be stored in one cubic foot of pit, trench and above-ground silos. While, the plastic tube (1000 gauge), 1.5m with and 2.5.m length can store 500 kg herbage. Ideally, 2–3 cms size of the chopped fodder is considered quite suitable for silage, but a one-inch size. of 15-20 percent pieces of chopped fodder keeps its fiber ratio to a suitable level.

·         The whole process of silage making – harvesting, chopping, pressing and packing – should be completed within 16 to 20 hours. Silage is ready for consumption as fodder for the animals in 4-6 weeks, or about 21 days for tube silage and about 45 days for other silo types. 

1.       Small containers and bags

These are containers with a capacity of up to 200 litres can be very effective silos. Such containers can be plastic bags (1000 gauge, to avoid any perforation for complete air exclusion), drums, etc. In all cases, the material must be packed extra tightly compared to other types of silos and kept under strict anaerobic conditions, meaning no air should be allowed to enter. Plastic bags with a thickness of about 0.1 mm (1000 gauge) can be used; bags must be tied at the top.

Multipurpose plastic tanks for silage making

Polythene tube for silage (1000 gauge), 1.5m width and 2.5m length

Illustration of steps in ensiling silage in plastic tube (ILRI Mnual 24)

2.       Stack/Surface or Above-ground silos

Stack silos are silos without walls and do not require permanent construction. However, they are the most prone to damage to the covering material, which would then lead to exposure to air.

Different stacking methods

3.       Pit or Trench silos

With pit silos, silage can also be made in pits that are dug vertically into the ground and then filled and compacted with the silage material. The trench silo is an adaptation of the pit silo, which has long been in use. It is much cheaper to construct than a pit silo. Construction is done on sloping land. A trench is dug and then filled with silage material. This method is ideal for large-scale farms where tractors are used. Drainage from rain is also controlled to avoid spoiling the silage. Trench silos are almost similar to underground bunker silos. These silos should have sufficient drainage as water can affect the quality of the silage. A sloping floor will also assist with drainage. If you use dirt walls, you must cover them with a plastic sheet to avoid soil contamination to the silage. The advantages of trench silos are that they are generally easier and cheaper to construct compared to bunker silos.  

Rectangular trench silo with polythene for silage

4.       Bunker silos

A bunker silo is constructed using concrete, sand, bricks/stones and cement for the walls but open at the top. The walls must be solid to sustain the sideways pressure from the silage, and must be sloped outward to allow for easier compaction right up to the walls. To avoid water damage, dig a ditch around the base of the wall and add drainage.

The advantages of a bunker silo are easier feed-out, less spoilage and easy filling. However, a bunker silo requires a more significant investment compared to most other silos.

Bunker silo

It is better to make a long and narrow silage pit to minimize exposure to air and therefore avoid warming up when you open the silo for feeding.

The execution of these stages has a big impact on the success or failure of the fermentation and the quality of the silage.

• The quality of the forage at harvesting time will depend on the season. During the rainy season, the forage will have a higher protein and sugar content, and a lower fibre content. Legumes and grass-legume mixtures should be harvested when the legumes reach the 10 percent bloom stage.
• The best time for maize and sorghum harvesting is when the crops are at soft-dough ripe and dough ripe stage.

It is important to determine the right time for harvesting fodder to get the best nutritional value from silage. Therefore, the time to harvest can be determined from when the plant is fully mature; half of the grain in maize or sorghum is milky; the fruitful fodder has 50 percent flowers; and moisture content is 65-70 percent.

1. Chopping

• Chopping is necessary to obtain good compaction and to exclude air in order to promote a rapid initiation of the microbiological processes and to take optimum advantage of silo capacity.
• Chopping is done with panga, common fodder choppers or chaff cutter or other specialized equipment like an electric chopper or the tractor’s shaft can hasten the chopping process. This may be a stationary chopper used when the forage is entered into the silo, or a pick-up trailer that chops the forage when it is collected in the field by modern harvesters.
• Chopping to between 2-4 cm lengths has the additional benefit of ease of ingestion, regurgitation and posterior rumination.

Chopped maize forage for ensiling

2. Wilting

• Wilting forage before ensiling increase the dry matter (DM) content as it reduces the water in the herbage to levels between 30 and 35%, hence effluents will not be produced when ensiled.
• Also the development of undesirable microorganisms will be reduced and better fermentation will be promoted and intake increased.
• The wilting time required to reach an optimum DM content depends on the herbage species and on the weather conditions. The time may vary between 4 and 24 hours depending on the thickness of the stems.

3. Conditioning

• Wilting time can be reduced when an electric chopper (pulverizer) or the tractor’s shaft can hasten the chopping process by crushing the stems, which results in improvement in the quality of silage.
• Crushing cuts the fibres and compresses the forage so that cellular juices will be extracted.
• Spreading the cut forage on ground or polythene tubing immediately after cutting and one more time afterwards will reduce wilting time.  

1. Filling the silo

• It is best to fill the silo and compact it as quickly as possible to minimize exposure to the air. In a bunker silo, before you start filling, spread the plastic on the outer edge of the floor and the walls and let it hang over the sides so you can cover the silo later (see figure below).

            Bunker silo: spread layers in U shape

• Deposit the forage at the beginning of the silo and spread the material in a thin layer (max 15 cm) throughout the silo. The thin layer will make it easier to compact the silo. Compact the layer and repeat the process until the silo is filled. If additives like molasses are to be used, sprinklee them on top of each layer once compacting has been completed.

2. 

   

   

3. Compacting the silo

• Proper compaction is the key to making good quality silage and is crucial in getting as much of the air out as possible. Good compacting is especially essential when using forage with lower moisture content.

                         Compacting the silage

• Compact each layer of the chopped forage material and repeat the process until the silo is filled. Once all the material is in the silo, continue compacting until the silage contains no soft patches. Critical areas for the silage are on the sides of the silo pit, so esure these areas are compacted as much as possible.
• The method of compaction depends on the silo dimensions. In vertical silos of 2 tons or less, compaction can be achieved by a person walking over the successive layers of forage. In horizontal silos, less than 4 m wide, compaction may be done by animals or people walking over the material. Larger silos require wheel or caterpillar tractors. The minimum width for mechanical compaction is 4 m. The tractor wheels or caterpillar must always pass over the inner border of the trail left during the previous passage, in order to guarantee homogeneous compaction. Mud or water accumulation around the silos must be avoided to prevent contamination of the forage.
• A silo has to be completely sealed against air and the chopped forage material has to be compressed in the silo to ensure fast development of anaerobic conditions and a rapid fall in pH. Under these conditions, Lactic acid bacteria, which converts some of the sugars (water soluble carbohydrates) in the plant into the pleasant tasting lactic acid, prevail over undesirable bacteria like Clostridia (which produce unpalatable Butyric acid) and moulds (which cause rotting of silage).

3. Covering the silo

• Cover the silo immediately after completing the filling and compacting. The cover needs to be made of an airtight material to avoid exposure to air as much as possible.
• A plastic sheet is the standard type of cover used. Ideally, use plastic that is at least 5 mm thick and keep the plastic sheet in contact with the silage over the entire area.

Weigh down your silage cover firmly with tyres, bags of sand, mounds of sand or other material placed closely together. Ensure the cover is airtight and watertight, and that there is no air under the cover.

• Overheating can signify that the moisture content is too low, the forage was too mature or too long, or the compacting was insufficient. Well-preserved silage can store for many years, provided air or water does not enter the silage silo.
• The amount of effluent flowing out of the silo indicates the dry matter (DM) content of the silage when the material was ensiled.
• Usually effluent is observed when the DM content of the silage is below 30%. For quick test to determine the DM content of the silage material, a hand-grab sample of silage can be squeezed.
• When moisture can be squeezed out of the silage, its DM content in below 30%., and this indicates that the crop has water, and should have been ensiled at a later stage or should have been wilted for a longer period of time before ensiling.
• When the moisture content of silage is too high, it forms favourable conditions for growth of harmful bacteria like Clostridia that results in unpalatable silage with a high content of butyric acid.
• The whole process of silage making – harvesting, chopping, pressing and packing – should be completed in 16 to 20 hours. Therefore, efficient and timely arrangements should be made for hiring of labour and required machinery relevant to the quantity of silage.

Delay in the preparation of the silage triggers harmful fermentation which reduces nutritional value. The filling and pressing process should be finished in a single day to initiate the process of useful fermentation. 

• The aerobic stability of silage is determined by: the maturity stage of crop cut; type of crop; moisture content of the material; degree of compaction; size of pieces ensiled; amount of foreign material in silage; and volume of leaves in ensiled materials.
• Poor aerobic stability results in the growth of yeasts and moulds. However, farmers can use inoculants containing Lactic Acid Bacteria that have the potential to improve the aerobic stability of silage by producing acetic acid.
• Mould growth drastically increases the risk of mycotoxins that may have a negative impact on health and reproduction of cows
• Ensiling in a bag avoids the hard work of having to excavate silage from the face of the pit silo daily. This reduces losses from aerobic spoilage usually associated with pit silos because a bag is fed out within a few hours or days. Spoilage losses can be very high (>50%) in pit silos when aerobic stability of the silage is poor. 

• The aim should always be to produce silage containing the highest possible energy and protein contents.
• Maize silage should have an energy value of 10.5 MJ ME/kg DM (total digestible nutrient content of 70%), crude protein (CP) content of 8 to 9%, neutral detergent fibre (NDF) content of 40 to 45%, and a starch content of 25 to 30% on a DM basis. Other analyses include ash, NDF digestibility, starch digestibility, acid detergent fibre (ADF), ether extract (EE), calcium (Ca), and phosphorus (P).
• The nutritional composition of Sweetpotato and Napier grass silage is shown in the Table. 

• 

• The length of time before silage is ready for feeding, however, depends on the quality of the forage used and the availability of forage to be ensiled.
• For example, newly made maize silage contains about 10 percent sugar, and since this could cause acidosis, it is especially important not to feed newly made maize silage too early. 
• Before feeding the silage, assess the quality based on appearance, texture, smell and colour. The silage should smell pleasantly acidic, e.g. the smell of sour milk or yoghurt. If there is a foul odour, it could mean that a specific acid, butyric acid, has formed. If the silage is wet and slimy, it means the silage is poorly fermented. If water can be squeezed out of a handful of silage, it means that the forage contained too much moisture during ensiling or that water has entered the pit. If the silage is brown or dark brown, this could be an indication that air has entered the silage and that the silage has warmed up due to inadequate compacting or sealing. The presence of mould or rot also indicates that air has entered the silage. 
• During the opening of the silage, the area exposed to air should be as small as possible and the time between opening and closing the silo as short as possible. Remove just the silage that you need and not more to avoid any exposure to air and heating. After feeding, keep the leading edge of the plastic sufficiently weighted down to prevent air from entering. 
• Most silage has a high feeding quality and should therefore be fed to the top-producing animals as a priority. Cows might need to get used to the silage in the initial period of feeding silage because of the smell; this hesitation disappears after a few days. Add a bit of molasses or other desirable feed ingredients to the silage to stimulate eating.
• In the ideal situation, cows eat 7 to 12 meals per day indoors; each meal lasts about 30 minutes, with a total eating time of about five hours per day. This means you need to provide new feed at least two or three times per day. Start feeding when there is about 5 percent feed left. Try to provide feed at the same times each day. Feed any concentrates at the same time as when feeding the silage.

• Hay can be used as animal fodder when or where there is not enough pasture or rangeland on which to graze an animal, when grazing is unavailable due to weather (such as during the dry season) or when lush pasture by itself is too rich for the health of the animal.
• Hay is also fed during times when an animal is unable to access pasture, such as when animals are kept in a stable or barn. 

• Hay can either be made manually, with simple mechanization like draught animal power or small tractors, or with fully mechanized systems. 

• In general, grass and legumes are used for hay-making. However, not all grasses and fodder are suitable for hay-making.
• To make better-quality hay mix legumes with grasses but avoid forage to which herbicides or pesticides have been recently applied.
• Harvest the fodder for haymaking when the crop has attained 50% flowering. At this stage protein and digestibility are at maximum, after which they decline with age.
• Fodder should be harvested after 2 to 3 days of dry weather so that drying will be possible. Where possible, drying should be done under shade so that the dried fodder retains its green colour, which is an indicator of quality. Turn the fodder using a farm fork, to ensure even drying.
• Check the dryness by trying to break the stem. If it bends too much without breaking, there is still too much water.
• Legumes and grasses can be mixed to make better quality hay, e.g. Rhodes grass combined with Lucerne. 

• Striving for high tonnages of hay while also trying to maximize protein and nutrient harvest is a good practice.
• Determining when to harvest in order to maximize both DM yield and nutrients can be done if the relationship between DM accumulation and protein content dynamics in the crop are understood.
• Generally, DM accumulates during the growing season and peaks late in the season. Conversely, forage quality is very high early in the season and declines as the season progresses.
• The goal is to determine at which point in time these two lines intersect. This point will determine when the best compromise between yield of DM and nutrients will occur.
• In the case of legumes, the point at which 10% of the flowers on the plant are blooming is the best time to cut for maximum quality and yield. In the case of most grasses it is best to cut after the boot stage, but before heading.
• Generally, hay is cut when about 10% of the crop is flowering. Plants must have a high leaf-to-stem ratio—the more leaves the better because they are packed with nutrients.

• Cutting the forage at the right time is crucial to make the best-quality hay. Cutting too early, when the forage is not very tall, makes hay to have a high moisture content, reducing dry matter. Cutting too late reduces the quality (protein levels), taste and increases losses.
• If harvesting is done too late, the forage is classified as straw. At the right stage, the plant is full of energy, protein and sugars but is not over mature, so that it produces tough, stocky hay.
• Forage crops produce more yield as they mature, but nutritive value and palatability decreases at first bloom or heading. Hence, good hay must be harvested to balance the best quantity with quality. Minimum cutting height is 10 cm, because, cutting too low will damage the crown and affect the plant’s ability to regenerate. Hay conditioning serves to “squish” the plant stems and leaves. This process helps extract nutrients and make it easier for cows to digest. It also increases the speed and consistency of drying.

• It usually takes 3–4 days for the hay to dry properly, so forage should be cut when expecting 3–5 days of sunny weather. Sunshine, wind and low humidity all help with the drying process. 
• Forage comprises of up to 90% moisture so a great deal of drying must take place.
• Extremely hot, dry weather can cause the forage leaves to dry too much before the stems dry causing the leaves to become brittle            
• 

  Hay drying in rows

• Baling can be done by hand or by mechanized balers. Generally, bail hay at a moisture content of between 15 and 18%. At this moisture content the hay fractures easily. Twist a bundle, and it will snap easily. There is almost no moisture anywhere, and the leaves shatter easily.
• Improperly cured hay (hay above 22% moisture content) can heat in the barn and cause a fire by spontaneous combustion.
• Square bales are used to feed in small batches. Round bales are used primarily for cattle. The hay is picked up in the front of the baler and rolled up into a large tube usually 1.8 by 1.5 m and weighing about 453 kg.
• Once the hay is baled, it is safe from the weather. Even if it rains, the outer layer of the bale will form a thatch of about 5 cm (2 inches), which protects the inner part of the bale. The bales are hauled out of the fields to the haystacks, which are located close to the areas where they will be used. The hay is stacked in stacks of about 170 bales each.

1. Small Scale Box and Pit Baling of Hay

• Bales can be made by hand using a simple wooden frame. The frame should measure 100 cm x 50 cm and be 40 cm deep and be open at the top and bottom as shown in the figure below.

                       wooden frame

• First, two lengths of sisal twine are laid across the frame and left to hang over the side. Hay is then placed in the frame, tightly compressed—for example by walking on the hay and then when the box is full of well-compacted hay, the bale is very tightly tied with the twine before pushing it out of the frame as illustrated in figure x below.

Pictorial representation of manual hay baling process

Manually baled Hay product

• A cheaper alternative to using a box is to dig a pit with the same dimensions as the box and then lining the pit with plastic paper. The rest of the procedure is the same.

                                A hay pit                   Lined hay pit

• Alternatively, a manual bale press or a mechanized baler can be used to bail ha Manual hay baling done using a baling box with dimensions 85cm long x 55cm wide x 45cm deep, open on both ends. If the hay is well pressed, the box will produce an average bale of 20kg

Manual hay baling illustration (Source, ILRI Mnual 24)

• Loose hay can be heaped into a dome-shaped stack and covered with a plastic sheet or it can be baled. However, storing loose hay takes up quite a lot of space; bales take up less space.
• Hay should be stored in a sheltered place, away from direct sunlight and rain. Wet hay can easily develop rot, and adequate ventilation is essential.

• Before you feed hay to your animals, it is essential to do a quality check. Ideally, the hay should keep its green colour. If the hay is not dry enough, it lowers the feeding value and can cause fires. Hay that is made correctly will have sufficient nutrients.
• Good-quality hay will improve the health of your animals and increase your productivity when combining with other quality animal feed ingredients.

• In the ideal situation, cows eat 7 to 12 meals per day indoors; each meal takes around 30 minutes, with a total eating time of around 5 hours per day. This means you need to provide new feed at least two or three times per day. Start feeding when there’s about 5 percent feed left. Try to provide feed at the same times each day.
• Grass hay usually has a lower quality and nutritional value than legume hay. However, pure legume hay may be too rich for many types of livestock. Therefore, feeding a combination of both grass and legume hay can make an excellent ration (70% hay and 30% legumes).