There is a long tradition of using acid based silage additives in Northern Europe. Initially only formic acid was used. We have produced formic acid at site Perstorp since the fifties and have sold it for the purpose of ensiling since the 1960s. Realizing the great benefits of using acid based silage additives, we also started to blend propionic acid (another product that is manufactured at site Perstorp) into the silage additives to increase the performance of the products. The most recent innovation sees the salts of these organic acids used to buffer silage additives for safer handling and easier transport. New technology has given ProMyr™ a more effective formula, which lowers the pH faster and prevents heating.
Benefits of acid based silage additives
To prevent bad quality silage, mixes of formic and propionic acid and their salts are used to improve the ensilage process. Good silage needs a fermentation that is in an anaerobic environment, reaching the right pH and thereby saving nutritional value and dry matter content. Our acids and their salts help that process in the right direction for our customers.
The first organic acid to be used to improve silage quality is still a staple in most acid based silage additives. Formic acid:
- decreases pH
- saves nutritional value
- kills unwanted bacteria
Formic acid decreases pH and stops the plant cell respiration. It also kills unwanted bacteria such as Clostridium before they convert into spores. A fast decrease of pH maintains the content of crude protein in the feed by killing the crop and in doing so causes the plant enzymes to cease their proteolytic activity. The process in which the plant uses its own protein as an energy source results in the formation of ammonia. Ammonia lowers the palatability in the feed and also decreases the crude protein quality.
Formic acid preserves the energy in the feed by instantly decreasing the pH and thereby saving energy that otherwise would have been used by the lactic acid bacteria to lower the pH. Our ProMyr™ products decrease the dry matter losses from around 15-5% by quickly killing the plant cells and unwanted bacteria.
Propionic acid is added to silage additives for other benefits than formic acid. The two work in synergy, as propionic acid:
- inhibits mold and yeast growth
- prevents heating processes
Propionic acid inhibits molds and yeasts. This prevents heating of the silage. Weak acids can penetrate the cell wall of e.g. a fungal cell. The cell tries to repair itself and uses a lot of energy for this. Eventually the cell will have used all its energy and dies. Weak acids can also bind to e.g. a yeast cell’ membrane protein and change its characteristics so that it loses its function. Even if the feed has a storage stable pH, there is a risk of yeast growth if oxygen is available. Yeast uses lactic acid as a nutritional source, which results in a higher pH in the silage and other unwanted microorganisms can start to grow and spoil the silage. Silage with a high dry matter content and a high sugar content has an increased risk of yeast and mold growth when the silo is opened. This can be prevented by propionic acid. Indication of yeast growth is measured in ethanol. With our ProMyr™ products the ethanol-level can be decreased by 60% compared to untreated silage.
Sodium formate and sodium propionate
Sodium formate and sodium propionate are used to buffer some of our ProMyr™ silage additives to make the product non corrosive and non ADR, and thereby safer to handle compared to the pure acids.
Sodium formate is the salt from the formic acid and it is effective against unwanted bacteria such as Clostridium. Sodium propionate is the salt of propionic acid. Just like propionic acid it is effective against molds and yeast. The latest generation of silage additives uses these salts with great success to improve the safety of handling and transport.
The search continues
We have been developing combinations of the products mentioned above for decades with more effort going into R&D every year. Formic and propionic acid are combined with different content levels of each acid depending on the type of product and the environmental conditions. Nowadays we work in close co-operation with farmers and universities to develop our products continuously. The history of acid base silage additives has only just begun!