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Improving Silage Performance Next Winter

How has your silage fed this winter? On many farms silage quality has been variable with some top quality silage producing good results whereas others, perhaps cut past the ideal stage due to weather, have required additional supplementation.

Producing quality silage has a direct impact on the bottom line.  Typical losses on a three cut grass silage system can be around 20% of the harvested dry matter of the material, made up of 12% in-silo losses and 8% feedout losses.  On the best managed farms this can be reduced by half to around 10% total losses.

A 20% wastage rate on a 100 acre first cut averaging 8 tonnes freshweight per acre would mean 160 tonnes are lost.  Kingshay put the cost of grass silage at over £30/t FW so reducing this by half will save over £2400, in addition to savings due to less concentrates being required.

The three main components of losses at silage making are the losses which occur in the field, including respiration losses while the cut crop is waiting to be picked up; leaching of nutrient losses when the crop is rained on; and leaf shatter when the crop is harvested.

Speed is the key to reducing in field losses.   The sooner the crop is picked up after mowing, the lower the respiration losses will be. Wilting is a way of managing the compromise between low dry matter (DM), effluent losses and high DM respiration and leaf shatter, so go for a quick wilt and don’t over wilt the crop.  The target DM for ensiling is 25-30% so there is little benefit from over-wilting.  Also avoid moving the crop too often, especially if it is dry as this will increase leaf shatter, a particular problem with clovers. More movements increase the risk of soil contamination.

The key to reducing in silo losses is managing the fermentation process and avoiding post-fermentation spoilage.  The aim is to ferment the sugars in the crop to produce fermentation acids, which are needed to drop the pH as quickly as possible from the 6.5 of the cut grass to pH 4.0 in the clamp. Ideally this occurs within 24 hours.  The greater the crop’s resistance to acidification (buffering), the more difficult it is to achieve a rapid and subsequently stable fermentation. Excess nitrates significantly increase the buffering capacity of the crop. A high concentration of nitrates normally indicates low sugar content. When this occurs it is difficult to achieve stable fermentation and the resulting silage is likely to have high ammonium N and butyric acid. Nitrate levels should be below 0.1% (1000 ppm) before cutting.

Axphast Gold is particularly helpful in low sugar conditions as its enzyme action releases sugars normally bound up in the fibre content of the grass and speeds up the fermentation process. These enzymes are also selected to release sugars such as xylose, galactose and mannose, preferentially utilised by the strains of bacteria in Axphast. This gives the enzymes an advantage compared to the naturally occurring lactic bacteria on the ensiled grass. The faster the controlled fermentation, the lower the risk of spoilage from undesirable, naturally occurring organisms will be. 

 

Conditions which allow higher DM silage to be made offer a different set of challenges - risk of spoilage shifts from the initial fermentation phase to the point of feed, when grass is either untreated, or treated with an inappropriate additive. Aerobic spoilage is generally initiated by yeasts, which oxidize the preserving acids causing visible moulding. Biotal Axcool Gold contains an organism called Lactobacillus buchneri which produces metabolites and promotes anti-fungal activity which kills off the yeasts and prevents spoilage.

 

As margins get tighter it is more important than ever to maximise the feed value and utilisation of silage, whilst reducing wastage.  Using a well proven inoculant such as Axphast Gold, AxCool or Supersile will help achieve this in difficult conditions. Speak to a Morton’s representative now on 028 40662521.


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