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Fundamental Principles

Why does grain need preserving?


Grain with a corn moisture content of over 14% cannot be stored and must be made suitable for storage. The use of chemical additives such as KOFA GRAIN -pH 5- has become quite widespread in this respect. This is a relatively low-cost and flexible procedure which requires little capital to be tied up in it.  

Without further treatment, the field fungi (fusaria), introduced when harvesting, can induce grain spoilage together with the storage fungi. Spoilage becomes visible by the differently coloured, sometimes football-sized hot spots and the brownish to greyish grain discolouration, usually accompanied by a stuffy smell.


Lots of mould fungi, which rapidly propagate in moist grain, can form dangerous fungal toxins in stress situations: the mycotoxins. Affected grain must not be fed out since this will affect the animals' performance and can induce diseases (see below).  

Good preservatives such as KOFA GRAIN -pH 5- stabilise the grain by inhibiting the propagation of fungi and yeasts and stopping grain spoilage. The feed stays tasty, rich in nutrients and hygienic. Even when the grain moisture content is less than 14%, several professionals swear by the preventative use of slight doses of KOFA GRAIN -pH 5-.

Why are mycotoxins so dangerous?


Mycotoxins are complex and toxic metabolic products of field and storage fungi. Moulds in grain only produce mycotoxins in certain stress conditions. What is often seen in practice is chronic poisoning (toxicoses) due to a continuous intake of mycotoxins, be it in small doses. 

Mycotoxins burden the internal system of farm animals. Specifically the liver, which serves as the detoxifying organ and has to break down these substances, becomes fully preoccupied and cannot take care of any other tasks.

The fusaria toxins deoxynivalenol (DON / vomitoxin) and Zearalenon (ZEA), resulting from field fungi (fusaria) are especially critical. DON-infected grain can cause reduced feed intake, and in extreme cases even a total refusal to eat, in pig fattening establishments. This will affect the animals' performance and health. In sows it may induce abortions and milk shortages. Fusaria toxins are normally present on the crop in the field.

The effect of ZEA is similar to that of the oestrogen hormone. In sows it may lead to false rutting and smaller litter sizes with weak piglets, as well as increased re-rutting.  

Ochratoxin is produced by a storage fungus. This toxin will cause general performance problems and may even lead to tumours in serious cases.  

Once these fungal toxins have been formed, they are virtually impossible to neutralize. And unfortunately these toxins are quite impervious to acids and heat. And 'mycotoxin binders' are not very effective helpers in this situation either. The only good option is prevention by cultivation measures and making the grain suitable for storage.

How can excessively high mycotoxin content be prevented?


Cultivation measures  

Withered plant material in the field offers mould fungi and other adverse organisms ideal conditions to grow. Shredding harvesting residues and ploughing them into the soil inhibits the transfer of such organisms onto consecutive produce such as grain. This specifically applies to close maize and grain crop rotation.  

If crops are too dense, this also stimulates the growth of field fungi, which should be avoided. Targeted species selection may also reduce infestation. Stressed crops are more sensitive to fungi than healthy crops.

Grain conveyor

Preventative measures during harvesting  

Effective grain cleaning always proves to be useful by sorting out foreign and poorly formed kernels and damaged grain. Straw residues also often carry fungal spores. It speaks for itself that the grain must be harvested as dry as possible. Grain damage due to the equipment having been adjusted incorrectly (combine harvester, grain conveyor) must absolutely be avoided since tears and cracks in the grain enable all kinds of harmful organisms to enter and stimulate spoilage.

Grain Storage

Storing grain  

Proper grain storage is critical for animal health and performance. In addition to carefully applying preservatives, the following instructions must be observed.  

Before storing the grain, the storage room must be cleaned scrupulously. The storage room must be swept clean thoroughly; corners and fissures must be freed from meal residues, dirt and cobwebs using a powerful industrial vacuum cleaner. Dust particles have often been infected with insects or their eggs or larvae, which will enter the grain stored and affect it. If necessary the storage room must be made free from insects with a suitable agent (e.g. Actellic) before introducing the grain.  

Once the grain has been introduced into the storage room the temperature in the grain stack must be checked every day. If the temperature is dropping slowly, the heat induced by harvesting is leaving the grain stack. However, if this trend reverses and the temperature slowly increases again, this implies that there is an increased microbial activity. If the temperature is 40°C or more, you have to act immediately. The grain must be shifted and re-treated immediately.

Grain storage

Grain batches of different moisture contents must be stored in separate rooms. If this is not possible, sheeting has to installed between them or all the grain must be preserved as required for the wettest batch. To avoid the chimney effect, the grain should be flattened out to remove any peaks after dumping.  

Applying silo paint or plastic silo sheeting to the storage floor has proven to be effective to provide mould layers in the grain. If necessary, plastic sheeting should also be applied to the walls to prevent such problems.  

Where possible the grain should be stored on an air-permeable gauze mat. This will allow the grain to breathe and reduce pollution due to cat's dung etc. In addition, make sure that there are no leaks in the roof through which water may enter and induce local moulding. These instructions also apply to storing maize.

What to do if grain has been infected?

If the grain is suspected to have been infected with mycotoxins, e.g. because the animals' health is worsening, this should be checked. Testing, such as the ELISA test, can indicate -quickly and at a reasonable cost- whether the grain is infected with DON. HPLC procedures which enable testing for DON and ZEA are more expensive and more accurate. These tests can be obtained from the LUFA research centre in Münster/Westfalen, in Germany, and from other suppliers. Private laboratories also offer these services.  

Infected grain is not suitable for feeding, or only to a very limited degree. Mixing it with non-infected grain may be possible, depending on the degree of infection and the animals to be fed. This must always be checked in every individual case.