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Maize Silage

How can I obtain mould-free maize silage?


Stable maize silage with high energy content forms the basic feed for lots of farm establishments.

Although several factors such as the variable weather cannot be influenced, the right choice of species, in line with the location in question, accurate crop management and careful ensiling enable the feed quality to be ensured even in less favourable conditions. Furthermore, the dreaded heating up of silo maize can be prevented when observing these guidelines.

Selecting the right type of maize


As is the case with grass, selecting a silo maize which is right for its location is important. Silo maize is associated with a high yield, high starch content and good digestibility of both the maize starch and the rest of the plant.

Different species can be recommended, depending on soil and climate conditions. Regional cultivation recommendations are drawn up by Chambers of Agriculture which regularly run trials and make their results available to farmers.

The right harvesting time


The cob is the main supplier of energy of silo maize. Harvesting early or late results in different starch yields and affects the digestibility. The optimum dry matter content of whole plants is between 28 and 35%. The energy concentration should be significantly higher than 6 MJ NEL / kg of dry matter. Conventional silo maize species are ready to be ensiled when the consistency of the kernels is mellow to firm, which is the case if the kernel can still be depressed when applying pressure with the nail of a thumb at the base of kernels from the centre of the cob.

"Stay-Green" species have been cultivated to extend the harvesting period. Where the kernels and the rest of the plant of conventional species ripen simultaneously ("in synch"), the actual plants of Stay-Green species stay green and continue the assimilation process for a relatively long time after the kernels have ripened. It is generally recommended not to harvest these species until the accumulation of nutrients in the kernels has finished. This can be identified by a black layer at the kernel base.

The cut height of silo maize

Cutted stems of a maize field

Cutting silo maize close to the soil is still popular. Although it is true that this increases the mass harvested, it lowers the energy per mass unit.

The stems contain hardly any nutrients, but all the more fungi, yeast and dirt. Combined with dry weather this will create optimum conditions for secondary fermentation processes in the silo. However, it would be better to cut the maize at a height of more than 20 cm from the ground. This will reduce the mass yield, but it will increase the quality of the silage. A 10 cm higher cutting height should increase the energy density by approx. 0.1 MJ NEL / kg of dry matter, which will immediately reflect in improved milk and fattening yield.

Professionals apply a high cutting method, directly below the cobs. Then the recommended cutting height is 30 to 50 cm, depending on the species in questi

Correctly adjusting the forage harvester


The recommended chop length for silo maize is 4-8 mm. The work result must be checked and the cutters sharpened regularly. If the chop length is too great, the silage may be too resilient, preventing optimum compaction, specifically in dry harvest conditions. This will only improve conditions for secondary fermentation at a later stage. The drier the maize, the shorter it must be chopped.

The cracker units must firmly hold and crack the kernels to enable their contents to be fermented. On the other hand, the combination of too short a chop length and the cracker units not being switched or being adjusted incorrectly will result in poor digestion of the silage due to the shorter dwell time of the feed in the rum

The shape of the silo

Perfect silage in a silo

The silo must be laid out such that a feed-out speed of approx. 1.5 metres is guaranteed in the winter months (a feed-out speed of up to 3 metres a week is required in the summer). When in doubt, a long silo is to be preferred over a wide silo, or two silos can be filled.

The silo face should be in the opposite direction to the prevailing wind direction. This prevents the wrap being "pumped up" by the wind, which might lead to an excessive introduction of air into the silo, resulting in aerobic deterioration.

Filling / compacting the silo

Compacting the silo with the tractor

To initiate lactic acid fermentation as quickly as possible, the silo must be filled as fast as possible. Filling the silo evenly and properly compacting the silaged crop are important to expelling atmospheric oxygen from the silo. The silo filling speed should not be determined by the forage harvester, but by the compacting tractor. If the roller tractor is relatively light, it should be fitted with narrow tires and drive slowly to increase the pressure per surface unit and extend the time during which the pressure is exerted.

The use of double tires, as shown in the picture, should be avoided. Although this reduces the danger of the tractor toppling over, it also significantly reduces the compaction pressure. The dimensions of the roller tractor should always be adjusted to the ensiling chain to ensure smooth and trouble-free operations and to avoid bottlenecks. Spreading the ensiling work over more days, or allowing long breaks when filling the silo, is not advised.

Our silage additives are used while harvesting the maize, and applied according to our recommendations. Check the adjustment of the dosing equipment in advance to rule out the risk of faulty dosing volumes.

Covering the silo

Leute beim Abdecke eines Silos

The silo must be sealed airtight by covering it with suitable silage wrap which is weighted down by spreading tyres, sand bags or earth over its entire surface. Avoid damaging the wrap since this would allow air to enter. When selecting the silage wrap, also consider its UV stability. For horizontal silos a strip of lining wrap must be drawn in between the silo and the silo wall, whereas the use of an additional wrap under the silo has also been proven to be successful. Lay the wrap such that precipitation water is fed away from the silo. Use reinforced mesh wrap to cover up the silo and protect the silage wrap against being damaged.

After sealing the maize silo wait for at least one, or preferably two months, before opening it. The main fermentation phase takes this long. If KOFASIL LIFE "M" is used as the silage additive, you will have to wait for 6 weeks to enable the bacteria to form the amount of acetic acids required to stabilise the silage.

If feed is required at an earlier time, a second, smaller silo should be set up. Never open silos whose fermentation process is still ongoing.

The problem of aerobic deterioration after opening the silo

Perfekte Silage in einem Silo

If the silo is opened after the appropriate fermentation time, good silage will be sufficiently stable to withstand a couple of hot summer days without warming up to a significant degree. Silages whose acidity has been lowered fast, and to which no or only a simple biological silage additive has been added, may suffer from a shortage of stabilising acetic acid. Although such silages have fermented well, they will warm up quickly after an influx of air into the silo.

Specifically if there are still pockets of air in the overall silo (through faulty spreading and compaction) the air will affect the silage and harmful yeasts will multiply. They breathe the lactic acids in the silo, causing the pH value in the silo to increase and mould spores to sprout. Decay will start and if this is combined with a low feed-out speed and continuously high temperatures, major losses, forage waste and a poor feed quality cannot be avoided. Silage batches exposed to these negative influences are dangerous constituents for TMR mixtures, since they will immediately contaminate the rest of the feed mixture with yeasts and moulds.

Special care is called for during long hot and dry spells (see the illustration of a maize crop of July 2003 near the German town of Ziesar). Withering leaves form the ideal culture medium for many fungi which can enter into the silo as well. Such crops must be chopped to short lengths, compacted well and should in principle be ensiled with MAIZE KOFASIL LIQUID. Otherwise you will eventually pay double for any ensiling error made now.

Silo cutting surfaces which have heated up are often sprayed with propionic acid, using a knapsack sprayer, as an emergency measure. However, this method has led to lots of accidents and has little or no effect other than to prevent fungi spores from sprouting in the locations where the propionic acid ends up. The penetration depth of the acid is no more than 1 to 3 cm and the result is mainly a cosmetic effect. To obtain some effect of treating the cutting surface, one should use a medium which is less aggressive than pure acid. Using KOFA GRAIN -pH 5- is advisable then.