Corn for Silage
Insight 406


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Silage is becoming more widely used in Dairy feed rations, to provide a readily available source of energy and fibre to the lactating cow, along with supplying the required nutrition for good herd health. To maximise the benefit from the crop grown for silage a few key guidelines need to be followed.

The best silage will always be made with good quality crops if it is containing weeds or other contaminants then the quality of the silage will be flawed from the beginning, when growing a crop for silage ensure you provide enough water and nutrition to the crop to maximise the yield potential, in addition if there are any stresses on the crop this will also either knock yield back or produce inferior quality silage or possibly do both.

Determine the correct cutting stage of your silage by following the guidelines around what type of crop is grown, what feed value you are targeting and the quantity v quality debate, you can contact your local Pioneer area manager for advice and more information around this to maximise your silage benefit. Grasses and Lucerne need a wilting time to drop the moisture levels to the correct ensiling levels this time will vary depending on the type of crop, density of crop, swathing width, and environmental conditions at the time of swathing. Most crops target moisture level at ensiling is between 60 – 70% moisture.

Corn silage is different it does not require any wilting time therefore harvesting of your whole crop corn silage will be determined by whole crop dry matter, ideally you should be targeting 35-40% dry matter, this will maximise your starch energy in the corn silage as the grain will be further developed which is where much of the starch comes from.

Once the crop is cut, it begins its fermentation process, simplistically this process can be broken down into 3 phases Aerobic, Anaerobic, and back to Aerobic again

  1. Aerobic – this is where the crop is still transpiring immediately after cutting and during the wilting process, also during the bunker fill the crop is still in the aerobic phase
  2. Anaerobic – this is after the crop has been ensiled and is in the bunker and under the plastic wrap. This phase initiates the Lactic Acid Bacterial (LAB) growth and pH decline
  3. Aerobic – this second aerobic stage is during the opening of the bunker and the face is exposed during feed out.

The goal of ensiling is to stabilise the crop via the action of the LABs. This reduces the pH through the efficient conversion of sugars to lactic acid. The quick lowering of the pH is critical to reduce the effect of the epiphytic (natural microbial population) populations that exist on the crop and can have a negative impact on the stability and feed value of the silage. The main epiphytic populations which cause the most problems in silage are yeast, moulds, and clostridia. These populations are not acid tolerant and are dormant during the Aerobic phase where the LAB’s drop the pH below 4.5.

Silage producers and nutritionists are constantly looking for ways to improve the quality and quantity of the silage produced. Scientific advances in microbiology have allowed these improvements to occur with the addition of inoculants to the silage during the harvest process.

The addition of a Pioneer Inoculant to your silage at harvest will help;

  1. Reduce silage pH and conserve sugars
  2. Reduce heating on increasingly large silage stack faces’
  3. Reduce dry matter loss
  4. Improve consistency and palatability of the ensiled feed
  5. Pioneers proprietary Lactobacillus buchneri strain is capable of producing fibre degrading esterase enzymes while it grows in the stack to allow for better fibre digestibility.

The keys to producing good quality silage are;

  1. Low pH – the more the efficient the decline in pH, the more water soluble carbohydrates will be conserved in the silage mass. Water soluble carbohydrates are essentially 100% digestible and contribute significantly to the overall energy value of the silage.
  2. Temperature – Silage temperature should be no more than 1-2o C above ambient temperature at the time of ensiling. If silage is faced and heating continues it is an indicator of excessive aerobic fermentation due to poor compaction, improper face management, slow feedout or failure to inoculate with L. buchneri.
  3. Proper spectrum of fermentation acids – the historic goal of 2:1, Lactic acid : Acetic Acid still stands today but with the addition of L. buchneri inoculant to your silage this will inhibit the growth of yeasts and subsequent silage heating. High levels of Acetic acid can be the result of uncontrolled growth of yeasts coupled with heating of the stack consuming the energy.
  4. Minimal microbial activity at feed out – a proper inoculated and ensiled silage pit will have very minimal activity on the face of the silage at feed out, moulds yeasts and mycotoxins can become present if the stack is not properly treated resulting in spoilage losses and herd health issues.
  5. Minimal Protein Degradation – A faster fermentation typically results in reduced plant and microbial proteolysis. Pioneer inoculants assist in the fermentation process and reducing the pH levels quickly for a stable silage.



Picture 1 – Untreated control     


Picture 2 - Silage treated with Pioneer Inoculant containing Lactobacillus buchneri

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Revised: April 2017