While wet ground conditions continue to hamper maize crops across much of the country, growers can still salvage the best feed value by crimping.

According to Michael Carpenter, technical director of feed preservation company, Kelvin Cave, those with access to the right machinery could consider harvesting maize as high-moisture grain.

This ideally means having access to a 4WD or tracked combine with a maize header. A crimping machine is then required to prepare the crop for easy storage, without the need for drying. The rolled crop can then be preserved as a high-energy concentrate feed, suitable for dairy, beef, and sheep, or for anaerobic digestion.

He says: “I know of several contractors with this machinery who are already harvesting and crimping large acreages of grain maize in this way.”

A particular attraction of switching from forage to grain maize in wet conditions is a less messy and problematic harvest.

“The combine will travel on a mat of shredded stalks and leaves, which is cut ahead of the vehicle, creating far less mud on tyres and roads,” he says.

“The combine can also deliver its grain to a gateway, avoiding the need for heavy trailers to traverse wet ground, and minimising soil compaction.”

Once back at the yard, the crop is passed through a suitable roller on the day of harvest and has a salts-based preservative, such as CrimpSafe 300, applied.

“The resulting crimped maize will typically have a metabolisable energy of around 14MJ/kg DM and over 70% starch, providing a cost-effective option for a high energy, home-grown feed,” he says. “Its high feed value is just as relevant for anaerobic digestion as it is for feeding livestock.”

However, if there is no alternative to foraging wet whole crop maize – such as insufficient cob formation or the lack of available equipment – great care must be taken with its preservation.

Independent silage consultant, Dr Dave Davies of Silage Solutions, highlights the challenges of preserving maize silage as the crop matures beyond its optimum dry matter of 32-35%.

“As whole crop maize matures, so its dry matter increases while its digestibility, energy content, and total harvestable yield go into decline,” he says.

“The plant, as it dies, also becomes more prone to fungal infection in the field, increasing the mycotoxin risk and greatly increasing the challenge of aerobic spoilage of the silage at feed-out.”

Higher dry matter in itself adds to the challenge of compaction and the risk of aerobic instability. In addition, the grain is much more difficult to crack, so attention to corn cracking every grain is essential. Higher DM is also associated with lower acid production, potentially compromising the speed at which starch reaches its maximum degradability.

All of this points toward the need for extra care in whole-crop maize preservation, according to Michael Carpenter.

“It’s why we would strongly recommend using the preservative, Safesil Pro, for high DM maize, in this year’s generally difficult harvesting conditions.

“This product has been formulated to deal with the challenges to aerobic stability we expect to see in the remainder of this year’s maize. It will inhibit the spoilage organisms – including those from soil contamination – which are likely to threaten its quality.

“We’d advise against a bacterial inoculant in these conditions, as these are unlikely to prevent the proliferation of the many undesirable organisms in this type of challenged crop,” he concludes.

* Crimping involves the rolling of cereals or maize grain through a crimping machine to expose the carbohydrate and protein, and the application of a preservative. This ensures a controlled fermentation and maximum nutrient retention once stored in an airtight clamp (or plastic tube). A range of modern preservatives allows cereals or maize to be crimped at moisture contents of 25%-40%. Crimp must remain sealed for at least three weeks and can then be fed throughout the year.

Why crimp grain maize

Produces high nutrient density, highly digestible concentrate feed

The process is simple – crimp, ensile, feed

Typical grain yield at 30% moisture is 4-5t/acre (10-12t/ha)

No drying or specialist storage is required

Avoids the soil contamination and compaction associated with late maize silage

Provides high-value animal feed or feedstock for anaerobic digestion

Improves animal performance (dairy, beef, or sheep) over dry-rolled grain

Backed by over 40 years of successful use in Finland and northern Europe