The ensilage is a method of Conservation Fourrage by wet process passing by the lactic Fermentation Anaérobie. According to the various techniques used, one obtains a fodder Acide of which the percentage of moisture varies from 50% to approximately 85%. In general, more the rate of Matière dries is high, more the Anaérobiose necessary to starting of the lactic Fermentation is difficult to implement. He encouraged the industrialization of agriculture and the dense breeding, except ground. He became at the 20th century an essential component of the systems of mixed-farming-breeding.

There exist several ways of Stockage and conservation of the Fourrage S:

• the dry roads whose result is the hay. The conservation is made possible by the dessication, either only under the action of the sun (natural drying), or supplemented by hot air produced by burners (drying in barn) leading to a percentage of moisture of fodder around 15% which ensures its stability.
• the wet process called “ensilage” , which applies as well to graminaceous fodder as to the Maïs and possibly to agro-alimentary by-products like the Pulpe of beet, the Drèches of brewery, etc It is however difficult to succeed with certain fodder like the alfalfa, low in soluble sugars and rich in nitrogen ( cf bad smells).

Technique

Around matter 50% dries , one obtains “ haylage ” whose conservation implies silo S-turns limiting the contact with the air. It is the thickness of the unit which ensures the anaérobiose (private of air or oxygen). This technique developped at the point with the the United States requires important investments (silo, blower, mechanism of désilage) and remains rather not very frequent in Europe. A similar effect is obtained today by the spiral wrapping of round balls (the anaérobiose resulting from the unwinding of a Plastic film around each round boot).

In lower part of matter 40% dries , one can really speak about ensilage. The technique most largely used is that of the silo corridor. Fodder is first of all chopped in particles of which the close length the centimetre, is stored flat, in successive layers, on a surface concreted between two walls, then compacted using tractors in order to expel the maximum of air intersticiel and finally put in anaérobiose final by covering using a ballasted cover of Polyéthylène.

The same technique can be used when one does not have walls limiting the silo, one obtains a silo taupinière then (frequent for the beet pulp).

The dry matter rate varies rather largely in the ensilages but it is possible to define values optimum to be tried to reach to obtain a fodder of better quality.

With regard to the Corn, the optimum ranges between 30 and 35% of dry matter. It is a value obtained naturally by the ripening of the whole plant. At this stage, the sugar content soluble, balance between grain and stem, the facility of compressing and setting in anaérobiose are most favorable.

With regard to the graminaceous fodder ones and the mixtures Graminaceous S Leguminous S, so of the similar values are desirable, they are only seldom possible because the content of dry matter of graminaceous at the time of harvest is only from 12 to 15%. By préfanage with the field one can make go up this content with 20 or 25%; this objective is sometimes risky because it requires a three beautiful days minimum of continuation (not always obvious at the end of April at the beginning of May). In the event of impossibility, it is possible to ensile the graminaceous ones directly but a content of matter dries lower than 20% conduit with losses by juice flow after the clothes industry of the silo. The ensilage the graminaceous fodder ones in spring, if it makes it possible to produce more intensively of fodder richer than the hays is also more delicate to control. The wealth in Protein S and soluble Sucre S of graminaceous decreases very quickly in spring. To differ harvest because of unfavourable weather conditions leads to a reduction in fodder quality some.

In all the cases, the production of fodder of quality is conditioned by the sugar content soluble which will be transformed into Lactic acid and propionic by the lactic Bactérie S naturally present on fodder, by the quality of compressing, the speed of the building site and the setting in anaérobiose and, consequently, of the acidification.

Another factor of quality is the length of chopping of fodder. The fodder preserved by this way are intended for the food of the Ruminant S. Of the too short bits, in particular with regard to the corn (dimension average lower than the centimetre), do not allow a good rumination of the animals whose ensilage is principal food and lead to a metabolic disorder called Acidose.

Authorized additives

They are conservatives aiming at increasing the speed of acidification, the stability and the shelf life of the ensilage. They are of three types:

• biological (selected lactic bacteria accompanied or not by sources of soluble sugar) increasing lactic fermentation. They are for example selected stocks of Lactobacillus plantarum , or inoculats including stocks of Lactobacillus buchneri , Enterococcus faecium and of Pediococcus .
• Acid formic and various acid salts causing an artificial acidification of bacteriostatic fodder
• (Sodium chloride and others) limiting the development of bacteria and the resumptions of alcoholic fermentation during the consumption of fodder.

Environmental and medical risks

The ensilage of fodder is a method of conservation biological often compared with the manufacture of the Choucroute, nevertheless measurements of hygiene are not the same ones. Several risks are to be limited:

• Risk of Botulism : it is related to the possible presence of animal corpses in the balls of plants or the silo.
• Risk of Intoxication by Toxin S fungic or bacterial: It is a risk which relates to the animals which consume products of an ensilage badly made (example: the Aflatoxine S).
• risk of contribution of Listeria in the event of badly acidified ensilage which allows the development of the bacterium (in particular in the dairy breedings, especially if one produced there cheeses with believed milk). There exist also risks of meningitis for the young nursing bovines nourished with the ensilage of corn and subjected to an important stress (conditions of breeding, brutal change of food, réalottement,…).
• Risk of toxic production of ethanol for the ruminants, generally following an alcoholic fermentation permitted by a bad sealing of the silo or plastic sheet.
• Butyric Risk of excessive presence of bacteria S , following the incorporation of ground in fodder during harvest. Without danger for the animals and the Man, they are prejudicial with the cheese-making transformation, and are responsible for bad tastes in the Fromage S with soft paste and for swelling and bursting for cheeses with pressed paste cooked like the Emmental. These bacteria can multiply and form resistant Spore S in the soiled ensilages; one observes also this phenomenon in the hays collected with ground residues, and which mildewed.
• Risk of pollution : The liquid produced by the ensilage of too wet plants is acid, corrosive, odorous and pollutant (powerful eutrophisant).
• Risk of Lead poisoning : the Lixiviat S of ensilage, very acids and corrodents, can facilitate the migration and the biodisponibility of metal pollutants, of which the Plomb accumulated in the ground, of metals coming from the silo, or the toxic lead of lead shot of hunting or Ball-trap easily and commonly trapped in fodder corn because of the shape of the sheets (in funnel) of the Maïs.

Impacts on the taste of milk or the meat

They are discussed, but it seems that the ensilage affects at least the taste of milk, less rich and less varied than when the animals eat hay or of course of grass in grazing ground.

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