Silage Preservation & ACTi prop technology

By Dr. Amit Kumar

Dairy Nutritionist, Trouw Nutrition South Asia


In India, throughout the year availability of good quality fodder is the biggest challenge for dairy farmers because feeding quality fodder is a necessity to maintain and improve milk production in the dairy animals, specifically high-producing animals need better quality forage. In this scenario, preservation of fodder becomes a necessity to meet the nutritional demand for milk production. And here silage-making comes into the picture to fulfil the demand for green fodder which can fulfil the nutrients requirement.

Silage is a type of preserved green fodder that is made up of fodder crops that are high in non-structural carbohydrates (like Maize, Bajra, Oat, and Sorghum) prepared in anaerobic conditions. Fodder crops which are having thick and juicy stems are preferred for making silage.

The anaerobic bacteria in the absence of oxygen utilizes carbohydrates to convert into lactic and acetic acids which reduces the PH and further inhibits the growth of microorganisms making stable nutrient value of the fodder crop.

But there are microbes in the fodder that can tolerate a wide range of pH (pH 2 to 10) like yeast & moulds which can remain alive even after huge temperatures and Ph variation, when they get a suitable environment (Oxygen), they start growing and produce toxins which are harmful for the animal health directly and indirectly for public health.

The silage development process can be divided into four phases:

  • Aerobic phase 1 – The phase may last from a few hours to 24 hours depending upon the amount of oxygen present.
  • Initial Anaerobic phase 2 – In this phase, anaerobic bacteria start producing acetic acid which starts reducing pH. The period of this phase ranges from 1 to 3 days in ideal conditions.
  • Main Anaerobic Phase 3 – due to the previous phase, pH reduces below 5.7 which supports the growth of lactic acid producing bacteria which produces lactic acid and rapidly reduces the pH of silage up to 4. The period of the phase ranges from 3 to 6 days.
  • Storage Phase – The period for this phase ranges from 7 to 21 days, in this phase pH of silage goes below 4 that inhibits the growth of harmful microorganisms thus making silage nutrients more stable. The storage phase completes up to 21 days but keeping silage closed for a longer period of up to 45 days makes nutrients more digestible and increases palatability for the animals. Production of lactic acid may continue up to 6 months in the silage which improves the shelf life and digestibility of silage.

So, it’s important to keep phase 1st for a very short time because in this phase due to aerobic oxidation nutrient value goes down, for this chopping of fodder crop within the length of 2 to 4 cm is required for better pressing and to remove oxygen from the silage. Proper pressing will ensure very little oxygen for the first phase, hence, shortens the duration. For making good quality silage: selection of crop, harvesting at the right time (½ to 2/3rd bloom stage) is favourable for better nutritive value. Dry matter content in b/w 65-70% is considered good for maize silage making.

High-quality silage should have minimum fermentation losses. In the entire process of silage-making, nutrient loss (Dry matter) may range between 5-10% and we aim to keep the losses towards the lower side. High starch content in the maize crop i.e. between 26-30% will ensure proper production of lactic acid by lactic acid-producing bacteria.

Proper packing of silage with polyethylene material or concrete and properly pressing with sandbags or tires is good for preventing ballooning on the top to avoid oxygen entrance and better anaerobic conditions for the fermentation process. Also filling of silo in a dome shape is favourable to avoid water seepage and proper drainage of rainwater.

When the silo pit is opened for feeding the animals, opened side comes in contact with oxygen that promotes growth of unfavourable microorganisms like yeast and moulds which produces toxins like aflatoxin and others, that are harmful for animal health as well as for human health.

ActiProp® Technology in Fylax Forte:

Organic acids like formic, sorbic, propionic, lactic, and acetic acids are used singly or in combination to efficiently preserve silage and avoid spoilage by protecting damage from microorganism like clostridia, yeast & moulds.

Optimum pH for good quality silage ranges between 38-4.2, which is suitable for the growth of lactic acid producing bacteria. This range of pH also stops the growth of yeast and mould also.

Organic acids when added in the silage directly reduce the pH supporting growth of lactic acid producing bacteria and inhibiting growth of harmful microorganisms (Cazzato et al., 2011). Propionic acid has been used for aerobic stability of silage by inhibiting growth of bad microorganism and competing on active sites with amino acids for binding or through altering the cell permeability of organisms (Queiroz et al., 2013). Adding propionic acid based organic acid combination has shown positive association for aerobic stability of silage, quality of fermentation and less nutrient loss (Gheller et al., 2021), simple organic acid have pungent smell and corrosive nature which can harm the handling person.

But inhibition of growth itself is not sufficient to avoid spoilage by yeast and moulds, as these microorganisms, whenever comes in conducive environment (in oxygen), start growing and producing toxins, hence causes spoilage of silage.

In the patented ActiProp® technology, propionic acid molecules are activated by disintegrating the cell wall and destabilizing the cell membrane, making it more permeable for organic acids to enter into the cell of the organism and ultimately killing the microorganism, which ensures better quality silage with longer shelf-life and enhanced nutritive value.

Additionally, it contains buffered organic acid which makes it safe to handle, less corrosive, and less evaporative so they will stay longer in silage for longer protection.

  • Increased Porosity of cell wall
  • Destabilization of cell membrane
  • Entrance of organic acid inside the cell of microorganism.
  • Decrease in internal cell PH —poor cell functioning— cell damage & cell death.


Silage is an excellent source of fodder for high producing ruminants. The harvesting crop should have correct DM content and fermentable sugars for ensiling. Careful management at the time of filling and emptying the silo can reduce the risks of aerobic spoilage and heating of silage. Additives like organic acids have been used to limit aerobic spoilage in the silo. Organic acids promote a rapid decrease in silage pH and improve fermentation quality thereby reducing the nutrient losses and retaining the nutritive value of the ensiled material. Organic acids are better suited to India as it remains stable even in hot and humid conditions which is not possible with the inoculants. Keeping in view of the corrosive action of organic acids. Trouw Nutrition’s novel patented product Fylax Forte with ActiProp® technology containing buffered organic acids and surfactants which helps in effective moulds and yeast control without causing any harm to the handlers.

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