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Essential information ahead of your Maize Silage harvest from biochemist Dr David Townsend

  • Major threats with ensiling
  • Minimising the risk of mycotoxins
  • OptiSile Maize®: A three-strain inoculant with a three-phase approach
Your maize crop that’s now close to harvest is an investment worth protecting. This high fibre and starch crop is a rich energy source for your livestock, but with low protein content, these nutrients need to be protected when stored.

In a rush? Watch a video of Dr David Townsend speaking below…

Ensilage Threats

Generally, ensiling can be thought of as a five-phase approach to preserving your fresh cut forage.

  • Harvesting
  • Clamp Fill
  • Initial Fermentation
  • Prolonged Storage
  • Feed Out

Each stage includes multiple factors that can influence the nutrient value of the silage at feed out. The final three contain major threats to the nutritional value of your stored crop, which if not managed properly, can require further investment to ensure adequate cow nutrition is maintained.

1) Slow Initial Fermentation: This leads to less acidic conditions in the clamp, allowing contaminating anaerobic bacteria to out-compete beneficial lactic acid fermenting bacteria. These contaminating bacteria (including Clostridia and Enterobacteria species) consume the energy rich starch and protein intended for your cows, leading to both dry matter and protein losses.

2) Degradation During Prolonged Storage: Improper clamp management allows aeration of the silage, which raises the pH and supports the growth of moulds, yeasts and pathogenic bacteria (including facultative anaerobes such as Listeria, Salmonella, Bacillus species, and E coli). These consume starch and protein resulting in further dry matter loss and can also cause serious health issues in cows.

3) Heating at Feed Out: Inadequate maintenance of anaerobic conditions during feed out allows the growth of aerobic stable bacteria and mould. This leads to excessive heating up of stored silage, leading to both in-clamp and in-trough nutrient losses.

Minimising the Risk of Mycotoxins

The greatest threat with improperly managed silage is the growth of aerobic stable organisms which produce toxic secondary metabolites. The most prevalent of these are fungi (including Fusarium, Aspergillus and Penicillium) which produce mycotoxins (aflatoxin, deoxynivalenol etc) that can cause serious illness to humans and animals. In cows, this can result in reduced milk yields, poor conception, high aborted pregnancy rates, and in extreme cases even death. Treating silage with mycotoxin inhibitors can prevent these, but the treatments take time to be effective and add significant costs to feeding.
Instead, it is more efficient and safer to get ahead of the mycotoxin problem by preventing contamination of your silage with these fungi, which can occur before, during or after ensiling, by following these inexpensive and easy to implement steps:

Step 1. Harvest at appropriate moisture content: This avoids ensiling overly dry forage, which makes it difficult to pack densely enough to ensure oxygen is kept out of your silage and achieve the necessary anaerobic environment (particularly with maize).

Step 2: Keep soil out of your silage. The pathogenic fungi you need to protect against occur naturally in the soil, so it is crucial to avoid carrying these into your clamp. This also includes avoiding soil contamination of the silage pile via machinery wheels whilst compacting.

Step 3: Thoroughly clean the clamp before filling. Remains of last year’s silage which have been open to the air can harbour dangerous levels of fungi that will rapidly colonise your fresh crop. Spores of these fungi can lay dormant for many years in empty clamps, harvest machinery, and even on the unnoticeable surface corrosion to concrete and metal caused by organic acids in silage. Power washing the clamp and all equipment ahead of storage minimises the risk of contaminating your new crop.

Step 4: Ensure anaerobic conditions. The most crucial step for impeding the growth of mycotoxin producing fungi is to ensure no oxygen can enter the silage. This means packing quickly, densely and with proper coverage which is then regularly inspected for damage during winter. At feed out, minimise the exposed face area and use a consistent rate to avoid over exposure of individual silage layers.

Step 5: Use a two-phase inoculant. Use a silage inoculant that not only promotes rapid acidification of the silage in the early phases, but also includes bacteria with anti-fungal properties that promote long-term air stability of the silage.

Maize Silage Inoculants

The high dry matter of maize makes it difficult to achieve and maintain the anaerobic conditions in the clamp which are required for optimum ensiling. OptiSile® Maize is specifically designed with this in mind and includes three species of bacteria which help with long-term air stability and protect against mycotoxin producing fungi. Optimum silage quality depends on a well-managed silage system in which the crop has been harvested at optimum dry matter; OptiSile® Maize has been added during the cutting process; and a clean clamp has been filled quickly after collection, with thorough compaction, and airtight sealing.

As soon as it’s added, the Lactobacillus plantarum starts producing large amounts of lactic acid to rapidly lower the pH (to ~4). This prevents the growth of other bacterial contaminants and ensures Lactobacillus is the dominating species (protecting against Threat 1).

During prolonged storage, the two other Lactobacillus strains used in Optisile® Maize slowly begin to convert lactic acid into acetic acid. In silage, acetic acid inhibits both aerobic and anaerobic spoilage-causing bacteria and fungi, stopping nutrient consumption and providing air-exposure stability (Protecting against Threat 2).

When the clamp is opened, the slower fermentation pathways of these two additional strains continue to produce acetic acid. The antifungal properties of acetic acid ensure no further fungi contamination can occur from the open face, giving the silage long term air stability at feed out (protecting against Threat 3).

Farmer’s experience of OptiSile® Maize…

At EnviroSystems, we base all of our products on this centralised model which we have called the BioCircle®. This puts farmers needs at the centre of our focus, and ensures that essential and valuable organisms, nutrients and chemicals flow from one area to another, providing maximum recovery and profitability for the farming community that we support.


Find out more at by phoning 01772 860085