In livestock production agro ecosystems, one of the most important productive activities is focused on ensuring the availability of feed for cattle, so the application of a conservation technique such as silage can offer an alternative to feed ruminants at any time of the year, the technique implemented can conserve the quality of the plant through the production of lactic acid, a product of the fermentation of sugars, as a means to ensure that the material lasts in an anaerobic form for as long as needed.
Aspects to consider in silage
Given the importance of this technique, there are several aspects to consider, such as the quality of the species to be ensiled, the type of silo to be used, the microbiological characteristics of the ensiled material and the organoleptic characteristics of the final product. Regarding the species, corn (Zea mays) is generally used in Venezuela, because this plant, in addition to its abundant foliage, has a fruit rich in soluble carbohydrates, which are essential for the fermentation process.
However, any forage plant can be ensiled, as long as it does not have a high moisture content (in cases of high moisture, the material must be pre-dried) because there can be a considerable loss of soluble nutrients through the effluents that are released from the material during the process; cut grasses are a good option, due to their great capacity to produce biomass, but in these cases the sugar content must be ensured to achieve an adequate fermentation, for this, there are different additives, a good option can be sugar cane molasses.
In relation to the type of silo, there are several ways of making silage, one of them is the famous silo press, commonly known in the area as silo chorizo, has an advantage in terms of storage capacity, which can exceed 100 tons of harvested material, but the big disadvantage is the high cost of the necessary machinery and the bag. However, there are other types of silos that can be more practical and economical, such as the pile silo, whose disadvantage lies in the loss of silage material, since it is not as airtight as the previous one. The choice of the type of silo is linked to the economic and technical possibilities of the producer, since there may be other options (bunker silo, trench, among others).
However, there are also microbiological variables that have a vital influence during the fermentation process, since the success of preservation will depend on the action of lactic acid bacteria capable of fermenting the sugars present in the silo, and thus producing lactic acid under anaerobic conditions, to acidify the medium and prevent the proliferation of harmful microorganisms. Generally, microorganisms can be found naturally in the plants to be harvested, however, the bacterial load may not be high enough to degrade the material, so there are some commercial and artisanal additives that increase the amount of lactic acid bacteria to accelerate the fermentation process.
In this sense, from Agrotecnia together with Professor Amesty (@amestyj), we have developed experimental trials to evaluate the use of artisanal products to increase the microbial load in the silo, such as buttermilk and fermented cow's milk, which achieved favorable results. After the fermentation process, silage was obtained with excellent organoleptic characteristics such as color, odor, moisture and texture, as well as an acid pH in a range of 3.5 to 4.5. The results indicate that there was a positive effect when using these products, which accelerated the fermentation process of the silage, which was uncovered 18 days after its elaboration.
On the other hand, it is important to mention that a quality silage must show the following organoleptic characteristics: an olive green color, a pleasant smell of sour fruit, a texture with well-defined contours and not excessive moisture. Achieving a silage with the aforementioned characteristics will depend on some factors at the time of processing, attention should be paid to several details that can affect the fermentation process, such as the size of the chopping, the ideal would be to cut the forage material of approximately 2 to 3 cm, in order to be able to compact efficiently and remove as much air as possible, make sure that the silo is as airtight as possible, once sealed, an air inlet can damage the material, avoid excess humidity, since harmful microorganisms can develop and cause putrefaction, use species with low buffering capacity, i.e., those that are resistant to pH decrease.
Scientific and technological contribution
The practice of anaerobic food preservation is a technique that has been developed a long time ago; however, at present, it is possible to continue the search to develop this simpler and more economical technology, generating in turn new lines of research that allow us to know the local resources that can be implemented for the good use and application of this preservation method.
On the other hand, to awaken the interest of small and medium-sized producers in the use of this technology, which offers a highly viable alternative in times of forage shortage for herd feeding.
Hernández, L. and Valero, Z. (2016). Effect of indigenous microorganisms and whey on the quality and stability of corn silage. (Graduate thesis). Universidad Nacional Experimental Sur del Lago. Venezuela.
Sanchez, (2014). Evaluation of silageability and chemical composition of canola and alfalfa forages with or without microbial inoculation. National institute of forestry, agricultural and livestock research. (Inifap) india agricultural research .48 (6). 422- 427.
Hiriart, M. (2008). Ensilados procesamiento y calidad. Mexico: Trillas.
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