Choose your silage inoculant carefully

There are more than 50 silage inoculant additives on the market, but to select the right one just remember three names:
  • Lactobacillus plantarum,
  • Pediococcus (two species), and
  • Lactococcus
Inoculants containing these bacteria have been shown to improve fermentation quality. The result is better intake, which leads to more milk or faster growth rates.

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Independent scientist, Dr Dave Davies of Silage Solutions explains that it is important to choose the right inoculant because of the way such bacteria work. They are known as homofermentative species and their job is to rapidly reduce pH in the clamp, which helps preserve protein and energy in grass to make better quality forage.

Check product labelling because all silage additives are registered with the EU Food Standards Agency and packet labels should state the contents.  

Concerns about visible spoilage at feed-out have driven the growth in additives containing heterofermentative bacteria as they can reduce aerobic deterioration. Yet, Dr Davies says the resulting silage is of poorer nutritional value and reduced palatability.

“These types of inoculants only improve silage stability by about 10 hours and give no benefit to animal performance,” he says. “It’s better to improve clamp management to prevent aerobic spoilage and use the correct inoculant because getting a good fermentation is more important.”

“Use homofermentative bacteria on all quality forage and it will improve it and stop the loss of energy and protein. You will even have more quality silage to feed, which certainly repays the cost of the additive.”

Farms opting for a multi-cut system to improve feed quality by ensiling higher-protein, lower-sugar leafier crops will also be clamping lower levels of natural yeasts and moulds found in the plant base. This automatically reduces the risk of aerobic instability problems, points out Dr Davies. “But fermentation is more challenging, so you should still use these additives because protein buffers pH in the silo and we need to help acid production in this high-protein grass.”

However, those who prefer a stemmier crop for bulk can struggle to justify the return on investment from using an additive, admits Dr Davies, “If you do it right and the weather is with you, there is no extra benefit. However, you won’t get as good a quality and will produce less milk from forage as a result.”