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Nov 19, 2019

Reducing silage heating

Nov 19, 2019

Lientjie Colahan

This winter there is a great opportunity to increase production from forage by reducing silage heating and waist and give margins a welcome boost, it will be really important to reduce silage waste.  All too often ‘waste’ is just associated with the mouldy, rotting and visibly contaminated feed on the top and shoulders of the clamp. But as Lallemand Animal Nutrition’s Lientjie Colahan explains there is a much more significant cause of waste. Heat.

Silage heating and waste

This is still a huge issue faced with all types of silage, but particularly higher dry matter ones such as maize and wholecrop, reducing the feed available and the nutritional feed value for the animal.

  • When a clamp is opened before the fermentation has stabilised, there is an increased risk of aerobic instability caused by undesirable yeast and mould activity which produces heat, reducing feed values.
  • Once a clamp starts to heat up, energy is being wasted and feed intakes reduced.
  • Clamps that have been opened before the fermentation has stabilised will continue to heat up throughout the winter meaning the waste over the whole season can be substantial.

The below graph demonstrates energy lost due to heating in an early opened clamp, as you can see in this case the silage treated with Magniva Platunim Maze inoculant stayed at a considerably cooler temperature due to rapid stability technology which inhibits yeasts and mould activities much earlier in the fermentation allowing you the flexibility to open your clamp in as little as 15 days from ensiling.

Reduce heating in silage

Under aerobic conditions, the yeasts and moulds present in silage use the sugars and lactic acid in the silage as a fuel source and as a result of this activity the silage will heat up.
(as visually demonstrated in the image below with the flur image).

How to reduce silage heating

As the lactic acid is used up, the clamp pH rises, other undesirable bacteria such as bacillus start to ferment and the silage will start to compost, losing nutritional feed value and palatability for the animal.

Stages of yeast and mould activity in silage

  • Yeast and moulds are present on all silage but remain largely inactive until they are exposed to oxygen.
  • Once yeast and moulds are active, the heat they produce will reduce energy content immediately.
  • Then, as the temperature of the silage increases, the digestibility declines.
  • Eventually when the yeasts and moulds have used up all of the lactic acid and sugars the silage will cool again but have considerably reduced nutritional value and palatability. (this is the stage you will visibly see the moulds)

Take action to keep silage cool

Not only does heated silage result in wasted forage it can also heat up the whole TMR, leading to contamination of the TMR, increased feed rejections, wastage of the whole diet and reduced yields.

Top tips for reducing the risk of heating at feedout:

  • Ensure all sheets are well weighted down throughout the winter, particularly on the shoulders and on any joins
  • Only expose the clamp in small wafers, pulling the sheet back a little at a time to minimise the silage exposed to the air
  • Work across the face quickly again to reduce the length of exposure to the air
  • Always use a shear grab or block cutter and keep the knives sharp to maintain a tight face
  • Remove all visibly wasted material and keep the area around the face clean
  • Clean feed troughs out regularly to remove any wasted and rejected feed to prevent contamination of new feed by the rejected feed

Planning ahead for next year, heating can be reduced by using an inoculant containing heterofermentative bacteria as their mode of action specifically helps improve aerobic stability by substantially reducing the number of spoilage yeast and moulds.

Magniva inoculants reduce heating

Magniva Platinum inoculants contain a combination of two bacteria strains, L buchneri NCIMB 40788 and L hilgardii CNCM 4785 which work in synergy. During the fermentation they quickly produce powerful antifungal compounds that significantly reduce the yeasts and moulds so improving immediate aerobic stability, meaning clamps can be opened safely much sooner. They also improve longer-term aerobic stability, protecting the silage while the clamp is open.
By significantly reducing the populations of both yeasts and moulds, the antifungal compounds produced by Magniva inoculants reduce the main cause of clamp heating and energy loss as well as increasing silage palatability.

In trials on maize, Magniva inoculants kept the silage much cooler, meaning more energy would be available to feed. Calculating the value of the heat, for a 1000 tonne clamp the extra energy retained by the Magniva inoculant would be enough to produce an additional 13,000 litres compared to an untreated silage. The more you reduce heating, the more silage you will have to feed and the greater the opportunity to reduce feed costs per litre.