Managing Maize for Maximum Margins

This KnowHow is focussed on getting the most out of your maize silage, whether you will be feeding it to your livestock or a ‘concrete cow’ – an AD plant. The customer case studies featured in this issue show that paying attention to detail throughout the ensiling process can result in considerable financial benefits, maximising the margins this valuable crop can yield.

Maize silage is very susceptible to aerobic instability due to the growth of yeasts and moulds in the clamp and at feedout. These losses often go unnoticed, and therefore unquantified, but can easily amount to more than 15% of the harvested dry matter (DM) being lost before it is used on the average farm or AD plant. The examples below put a value on such losses in three different situations.

1000t maize harvested at 30% DM (300t DM) and 11MJ/kg DM = 300,000kg DM and 3,300,000MJ.

For Milk Production:

Approx 5MJ to produce 1 litre of milk therefore 300 tonnes of DM has the energy equivalent of 660,000 litres

Below average 10% DM loss due to aerobic instability = potentially 330,000MJ lost

330,000MJ ÷ 5 = energy potential for 66,000 litres

66,000litres @ £0.20/litre = £13,200 potential milk value lost

Therefore, reduction in aerobic instability losses from 10% to 9% could equal £1,320 extra margin

For Beef Production:

Approx 38MJ to produce 1kg of beef therefore 300 tonnes of DM has the energy equivalent of 86,842kg meat

Below average 10% DM loss due to aerobic instability = 330,000MJ lost

330,000MJ ÷ 38 = energy potential for 8,684kg meat 

8,684kg @ £3.40/kg = £29,525 potential meat value lost

Therefore, reduction in aerobic instability losses from 10% to 9% could equal £2,952.50 extra margin

Or, for a typical 250kw combined heat and power unit (CHP):

125m3 raw biogas/hr required to run the engines

1kg of Organic DryMatter (ODM) maize will produce around 700 litres of raw biogas

Assuming 30% DM of which 97% is ODM 1 tonne fresh weight maize will produce 203.7m3 of gas and run the engines for 1hour 36minutes = 400kWh

Income from 1t of above maize:

Feed-in Tariff 9.23p/kWh    = £36.92

Export Tariff   4.85p/kWh   = £19.40

RHI Payment 6.06p/kWh    = £24.24

                              TOTAL     = £80.56 (£269/t DM)

Therefore, reduction in aerobic instability losses from 10% to 9% could equal £26.90 extra margin/tonne DM

So, how can these expensive losses be minimised? The answer is to adopt a complete, scientifically proven, ensiling system that addresses all the causes of aerobic instability losses, from a company whose sole focus is on helping you get the most out of all your home-grown feeds.

The first golden rule is to ensure that clamps and all crop-handling areas are cleaned thoroughly; pressure-washing clamp walls and floors is not time wasted, it is good practice and essential to reduce the risk of harmful microbial contamination. Equally important is to line the clamp walls with good quality, new, side sheets. Kelvin Cave Ltd supply ready-to-use 50m lengths of high quality, heavy-duty side sheeting 4, 5, or 6 metres wide designed for this purpose.

The next step is to apply Safesil through the forage harvester as the crop is cut. Safesil, with its unique, three-way blend of human food preservatives, has been shown to “guarantee prolonged storage stability” (Journal of Dairy Science 94:824–831).

Once clamp-filling commences the key to success is COMPACTION, COMPACTION, COMPACTION!! Silage-makers around the UK have found that the use of a SilaPactor for this vital process saves time and fuel and makes the job of layering the crop effectively far easier because the buck-raking tractor has a firm, level surface to work on. We often hear from farmers using a SilaPactor who say they “wouldn’t want to make silage without it”. 

The SilaPactor has been shown to increase compaction density by up to 40% when compared to conventional tractor/loader rolling, and, when used in conjunction with a SilaBlade, makes filling a maize clamp an efficient and stress-free process. More importantly, the greater the amount of air removed from the silage mass the lower the fermentation-DM losses will be. Poor compaction means less efficient use of available clamp space and allows any remaining nutrient-wasting microorganisms, mainly yeasts and moulds, to grow and use valuable energy and DM.

The final piece of the maize silage-making jigsaw is to seal the clamp with an effective oxygen barrier sheet and protect this from damage during the storage period. Farmers and AD plant operators the length and breadth of the UK are finding that Kelvin Cave Ltd’s O2 Barrier 2in1 top sheet, weighted down and protected by our heavy-duty ClampNet and gravel bags or ClampTiles, is the most cost-effective, labour-saving and simple system to achieve this vital finishing touch. O2 Barrier is the single-sheet solution that separates and transforms into a vacuum film and top sheet on the clamp. Used in conjunction with the side sheets to form a ‘Warner’s Corner’ (visit: this system will give protection to your valuable maize silage from start to finish. 

Make the most from your maize this year by adopting the complete Kelvin Cave Ltd ensiling system. Whether you’re producing milk, meat or gas our scientifically-proven solutions will ensure lasting success for your business.

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