Let's talk about microbial additives in silage

In tropical regions, to counteract the critical periods of forage biomass production by pastures, forage conservation is used specifically silage which is a wet conservation method that is based on fermentation under anaerobic conditions. During this process, the formation of lactic acid bacteria begins, which ferment soluble carbohydrates to lactic and acetic acid in a smaller proportion. This fermentation process to preserve the plant material can last between about 21 and 30 days and depending on the production of lactic acid will be the stabilization process to maintain the pH levels at about 4.2 and no microorganism appears that causes putrefaction.

Of course, if we talk about forage conservation, the plant material that is placed in the silage is mainly grass, some cereals such as Corn and sorghum, forage legumes and other plant material that provides adequate nutritional levels to the animals. For the fermentation process to be successful, there must be sufficient levels of soluble carbohydrates, therefore, molasses is added to some forages and also an adequate amount of lactic acid bacteria to be able to produce lactic acid.

In this same vein, it can be seen that the microflora present in the fermentation process in the silage plays a fundamental role so that the plant material can be preserved, there are desirable and undesirable bacteria, the former help the production of lactic acid and the latter can cause the putrefaction of the silage material. For this reason, for several years the use of microbial additives has been started to improve the fermentation conditions in the silage process, a practice that has become very common to this day.

For the aforementioned, commercial products containing a high concentration of lactic acid bacteria began to be developed, helping a fast and efficient fermentation to occur, these additives have their advantages, but sometimes they can be very expensive, therefore, research began to be carried out using local resources as additives such as cut milk, whey among others, which help the inoculation of microorganisms that help the acceleration of the fermentation process.

In our country Venezuela, in many universities where careers related to the agricultural sector are taught, experimental trials have been carried out with cutting grasses, corn, where inoculation with the aforementioned local resources has been used and favorable results have been obtained regarding the fermentation process. Similarly López and Ortega (2006), tested the inoculation in trials using serum and pointed out that favorable responses are found in the decrease in pH and an increase in the lactic acid ratio compared to silages not treated with inoculants.

Therefore, the use of inoculants with bacteria has increased in livestock agroecosystems where this alternative of bovine feeding is put into practice, since it is also considered that certain inoculants are natural products, without risk in their handling and that they do not cause environmental problems, for this reason, this issue of inoculation has been one of the most studied variables when talking about the practice of silage.

It is also important to mention that to determine if the silage process is successful, and a quality preserved material must be considered some physical, chemical and organoleptic parameters such as odor, color, humidity, ph and temperature. Among those mentioned, the one that indicates that there is an adequate production of lactic acid is the pH, that's why it should be maintained with values close to 4.2, which guarantees that there will be no proliferation of undesirable microorganisms.

Dear readers, to conclude, it must be made clear that the quality of the vegetative material will not depend on the fermentation process, the quality will depend on the optimal harvest time, in the case of grasses when it is very mature the protein levels decrease and the fiber levels rise. It was also evidenced the importance of microorganisms in the silage process, specifically the bacteria that help the production of lactic acid, it would be interesting to perform some tests with worm leachates after an analysis of the product, to see if it can provide the necessary microbiota for anaerobic fermentation and obtaining suitable forage material to be supplied to ruminant animals at critical times.