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Maize Harvesting

Early in August it looked like maize was going to ripen very fast and be ready for harvest in Early September. Now 3 weeks on, the crops haven’t changed much so harvest dates are looking more like normal. Some of you have bumper crops this year, perhaps more than you need as forage so this is a good time to consider other options. Some contractors have headers for foragers offering options and we want to explain some of these – but first make sure you have enough bulk feed. If you are unsure how much maize you need to cut as silage then please contact us now so we have time to measure up existing silage stocks and calculate maize requirements.

Assessing your Maize pre-harvest

It is important when assessing crops through out the year to ensure that you get a good quality crop in your clamp.

  • Milk Line Test: Break the cob open halfway down and remove one of the grain kernels. The milk line is where the solid starch ends and the liquid milk begins. The ideal is to have 75-100% of the kernel yellow in colour (starch) instead of being milky, and for no liquid to be excreted when pressed

  • Stem Test: Cut the stem of the plant at the same height of the forager header. Then squeeze the stalk to see how much moisture comes out. If it is easy to squeeze water out of the pith it is not ready to be cut, if very little it is ready to be foraged as long as you have assessed the cob also.

  • Oven test: pick 4-5 plants and chop them up to no more than 2 cm pieces. Weigh a baking tray and add 1kg of chopped maize, put it in the oven at just under 100oc for 8 hours, allow to cool and weigh again. If the weight is now 350 g more than the empty tray it is 35% dry matter.

  • Dry Matter: The target dry matter for cutting 32-35% DM, if you get the standing maize in the field tested for dry matter the target for standing is 28%. We would suggest at this stage you get in touch with your contractor to book in your forage for harvest as the dry matter increases by 2% every week.

Clamping Management

  • Well consolidated, having an extra tractor rolling at. This is a large investment and is the most important part of the harvest

  • Aim to fill the clamp in thin layers, using a shallow wedge to ensure the whole clamp including the shoulders are well compacted, see diagram

  • By filling in this “U” shape you get better compaction but also reduce the chance to cause damage to machinery by catching the RSJs

  • Sheeting is important to reduce dry matter losses, side sheets, cling film layer, plastic and heavy-duty cover will all improve the feed out quality

  • Weight on the sheet, sandbags around the sides and on top. Using bales on the ramp will significantly reduce wastage and spoilage on the ramp.


As it stands now, there should be little need for any additive – the best additive in our view is diesel in the tank and extra rolling.

Options for Surplus Maize

If you have a genuine surplus of maize the options to consider are:

  • Shredlage

  • Corn cob mix

  • Crimped maize grain

Shredlage, what is it?

Shredlage is another method of harvesting your maize crop. To put it simply the maize crop is cut longer at harvest and the unique Shredlage and kernel processor shreds and chops the crop to a length of 25-30mm and crushes the kernels more thoroughly increasing the amount of starch available to be digested in the rumen.

What it means to the cow

With the chop length is significantly longer than the conventional maize foraging method, this larger surface area will add more structural fibre into the ration, reducing the amount of straw, hay or Lucerne that may be needed in the ration. However, there could be more sorting of the diet and possibly more wastage of the longest pieces.

As the Shredlage processor crushes the kernels more thoroughly and finely, that means the starch is more digestible in the rumen. This should be viewed as a double edged sword, as the cow will be digesting more starch in the rumen this will give more energy initially but may cause problems in diets that already have other rapidly fermentable starch sources (rolled wheat, rolled barley etc.). Rumen pH levels to drop if the diet is not balanced correctly, that would lead to reduced production and inefficiency.

With more of the starch being absorbed in the rumen this reduces the overall amount of bypass starch in the ration which will have to be sourced from elsewhere to provide the cow with the correct energy for the upcoming lactation.

Corn Cob Mix

Corn Cob Mix (CCM) is the harvest of ripe maize including the spindle, sheath and grain. This process of harvesting uses a row-dependant grain maize header that removes the cobs from the stem and cracks the grain. The stem is chopped up leaving a swathe behind the harvest that forms a mat on the stubble. This swathe can be put back into the soil as a green fertiliser but something to bear in mind, this may cause Eyespot problems for your next cereal crop.

CCM is more commonly used on over ripe crops it usually gets harvested 10-14 days later than conventional maize silage, this method of harvesting ensures you get the highest nutritional return from your maize crop if over ripe.

How does it compare to conventional maize silage?

In terms of tonnage you would be looking at 12-18T/Ha, dry matter 45-55%, starch content 40-45% and a ME of 13. A very different feed to maize silage a lot dryer, more starch and energy overall, this is a very high energy feed that would be recommended to feed to high yielding cows.

Ideally we recommend the production of CCM after a full forage stock for the upcoming winter has been completed. As if forage levels will be tight or even short for the winter sourcing external forage may become difficult.

Crimped Maize

Crimped maize is very high energy feed and is seen as an alternative to bought in concentrates. The harvesting process for crimped maize requires the crop needs to remain longer in the field, somewhere in the region of 4-7 weeks after the maize silage crop. The crop is cut using a conventional maize picker header attachment, it shells the corn during this process. The corn is then fed into a crimper which will expose the endosperm.

To reduce any aerobic spoilage, we would recommend that you tightly pack your clamp, roll and ensile tightly with sheets, sandbags and cover with weights (Tyres, rubber mats etc.) across the surface.

Ideally we recommend the production of crimped maize after a full forage stock for the upcoming winter has been completed. As if forage levels will be tight or even short for the winter sourcing external forage may become difficult.

How does it compare to conventional maize silage?

Crimped maize will yield 9-12 T/Ha, it will have a dry matter of 65-70%, the starch content will be 65-70% and will have a ME of 14.5. This is a very energy dense feed and would be a fantastic source of homegrown starch in the diet, as a feed source crimped maize would best fit well in die

ts for high yielding milking cows or finishing beef.

Please call one of us if you want to discuss the options.

Lewis Graham 07904 601104

Sam Kelly 07777 696080

Pete Kelly 07970 942668

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