Why use Silage Inoculants and Which are Best?

December 1, 2014

Why use Silage Inoculants and Which are Best?

Farmers often ask if silage inoculants are beneficial when making forage silages, and my answer is yes, irrespective of situation and type of crop.  It is a matter of risk and limiting losses, of dry matter and nutrient value, at every stage in silage making and utilisation.

Plants naturally have several varieties of bacteria, yeasts and moulds on them prior to harvest, but numbers and types of microorganisms present are not ideal for optimal fermentation.  Not using a good inoculant increases the risk of poorly ensiled and unpalatable silages.

Silage inoculants are widely accepted and used globally, with the best bacteria and combinations made by a handful of specialised companies.  These companies spend millions of dollars on R&D, to identify the most effective types and combinations of bacteria and enzymes.  They also undertake extensive independent trials to assess efficacy and gain EU and FDA approvals.

When selecting silage inoculants it is best to purchase brands from companies sourcing their bacteria and enzymes from one of these specialist manufacturers.  Using these products is likely to result in better silages than those using unselected bacteria from the bakery and brewing industries, or relying on pre-application fermentation to increase bacterial numbers, or enzyme only products.

The best brands deliver high levels of viable live bacteria (no less than 200,000 CFU’s / gram of crop).  High bacteria numbers are not the whole answer, as the types and combinations are also important.  Bacterial strains should work as a relay team during early fermentation stages, as each work best at different pH’s, to lower the pH as fast as possible, as this minimises dry matter losses.

Inoculants should also contain a specific bacteria strain to minimise the growth of clostridia bacteria, which can result in less palatable silages.  Voluntary intakes of such silages tend to be low, and they can increase the risk of thermoduric grades in milk.  Some inoculants may also contain a specific bacterial strain to improve stack or pit stability, in cases of slow utilisation after opening, or in damp hay, where heating may become a problem.

Good inoculants may include enzymes to help unlock sugars that would otherwise be tied up in plant structural fibre.  Enzymes are most beneficial with low sugar crops, such as those harvested in damp and cloudy conditions.  Bacteria require sugars to grow, multiply and produce acids to preserve crops.

Many NZ farmers believe it is more important to use inoculants on maize than other crops.  In fact grass and particularly lucerne crops are more difficult to ensile successfully due to their higher buffering capacity.

As featured in NZ Dairy Farmer

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