Heatwaves and silage, how to get the best results

Heatwaves and silage, how to get the best results
Maize silage

Maize silage is the most popular cereal crop for preservation through ensiling. Ideal Dry Matter (DM) for harvesting maize is between 32-35% and it is preserved in the same was as grass silage – in a clamp. Maize is easy to ferment due to high sugar & DM content, because it is high in sugar it is also high in energy, and due to its palatability is likely to increase DM intakes, thus benefitting overall milk yields and quality.

A large advantage to maize is that it only requires one harvest a year & unlike grass for silage, does not require wilting, making it a time efficient crop to cut & ensile. It also compliments a diet based on grass and or Wholecrop silage well.

However, maize is not suitable to be grown in cold and wetter climates, such as that of northern UK & grows best on flat land. It is a weather dependent crop also, meaning it may struggle in periods of drought and extreme heat. Once harvested, its high DM can also make it more susceptible to aerobic spoilage, so an additive may be required to help prevent this.


Severe weather impacts

There are different ways in which maize can be impacted by severe warm weather & drought. This depends at which stage of development the crop is, if the plant has not yet begun flowering, dry weather can impair the overall growth & prevent ear formation.

If the crop has begun to flower and then faces hot weather, this can affect the pollination, if the plant does not pollinate & has long green silks (the female part of the plant), then it is likely the silks emerged after the pollen has been shed & therefore no kernels will form.

This can be avoided in severe periods of drought through irrigation, the tassels begin to shed pollen (the male part of the plant) a day before the silks emerge, and so around one week before they begin to shed pollen, approximately two inches of water should be applied. This is crucial to ensure a good maize yield as 50-60% of yield is from the cob, therefore good pollination is very important.


Make up for potential shortfall

Now is a crucial time to consider making up for potential maize silage shortfalls by ensiling wholecrop as silage as opposed to harvesting the grain. Dependent on the crops DM, harvesting wholecrop between 30-40% DM gives the maximum amount of fresh weight, and is suitable for young stock / dry cows due to its lower starch content. Harvesting between 40-50% DM gives levels of higher starch but as the crop is drier, it is harder to keep aerobically stable and is harder to compact in a clamp, therefore an additive may be appropriate to help prevent the crop from heating.

When harvesting above 45% DM it is likely a processor will be needed to ensure the kernels are cracked, the same applies to wholecrop harvested between 50-55% DM. despite having higher starch levels again, consolidation will be far more difficult. Ensure the clamp is filled slowly with ample weight to ensure good compaction & prevent any air pockets forming as this will result in mould and wastage.

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