Crimped maize is growing in popularity. We outline the feed’s potential benefits, including adding flexibility to forage plans, and offer some agronomy pointers.
TEXT WENDY SHORT
Crimped maize has the potential to be a valuable addition to dairy rations and it also offers a high level of flexibility. So says KWS’ Tom Turner, explaining that this is because decisions can be taken in late season about whether to produce silage or grain from the standing crop.
“Key to producing good-quality crimped maize is access to light land in a location with the potential for an early harvest, because crimped grain is taken a few weeks after the standard timing for cutting a forage crop,” he explains. “Providing that a suitable site is available, crimped maize is an extremely nutritious ingredient in dairy rations.”
Yielding between nine and 12 tonnes of fresh grain per hectare and containing high starch levels, crimped maize is produced by threshing the grain from the cob, leaving the stover and stubble behind on the soil surface.
“There is no drying requirement for crimped maize, which has an average dry matter of between 65% and 70%. Instead, the grain is crimped on farm to break open the grains and expose the endosperm, improving its digestibility,” says Mr Turner.
In terms of nutritional value, an average crop of crimped grain will have a starch content typically greater than 70%, with an ME of approximately 14.5MJ/kgDM. “And it contains between 25% and 30% by-pass starch and this puts it above other feedstuffs like maize silage and wholecrop cereals.
Rocket fuel
“Maize silage is often referred to as ‘rocket fuel,’ but crimped maize offers an even greater level of nutritional value,” adds Mr Turner. “There is also a much lower risk of acidosis compared with feeding barley and wheat starch, which are digested more rapidly. Crimped maize’s high by-pass starch content means that it can be digested in the small and large intestines, reducing rumen load and helping to balance rumen pH.”
Crimped maize is widely grown in countries including the Netherlands, France and Denmark, and it is also produced on a number of UK dairy units. Producers who would like the option of setting aside a proportion of a standing maize crop to produce crimped grain should select an early maize variety.
“Early varieties offer an advantage as they can bring forward harvest dates,” says Mr Turner. “They produce plants that will reach maturity with fewer heat units than a mainstream variety.”
Early varieties
Some modern earlies have the ability to mature in as few as 130 days, while mainstream varieties can take up to 160 days to reach point of harvest.
Varietal selection for crimped maize should also take lodging and brackling scores into account.
“The slightly later harvest date requires that varieties have a good rating for standing power and they should also be low risk for brackling, which occurs when the plants break below the cob as they mature,” adds Mr Turner.
“Drilling at a seed rate of 90,000 seeds per hectare is ideal, as the resulting crop will be appropriate for harvesting as either forage maize or crimped grain. As a rule, a low seed rate will maximise cob growth and encourage rapid maturity.”
Contractors will need to be geared up for crimped maize production, stresses Mr Turner. “It requires a specialist header to be fitted to a standard combine harvester. In response to demand in the appropriate areas for producing crimped maize, many contractors have added it to their range of kit.
“But it is a good idea to check that the local contactor has the necessary equipment and that the crop row spacing matches the contractor’s harvest machinery settings.”
He says that it is not easy to set a precise figure for the delay in the crimped maize harvest after the forage crop has been cut, because a lot will depend on the individual site, the chosen variety and, of course, the weather. “I would advise the use of an additive before storage, to improve fermentation and to promote aerobic stability.”
Land benefits
Crimped maize also offers land benefits post-harvest. “When harvesting crimped maize, the chopped stover is returned to the field and enhances the soil organic matter content. This layer on the soil surface helps to minimise erosion and ease ground travel,” explains Mr Turner. “But it will take longer to break down compared with a cereal stubble and it can lead to nutrient immobilisation.
“So consult an agronomist or crop nutrition specialist for advice on the appropriate nitrogen rate, to optimise organic matter breakdown. This will have to be factored into the rotation on mixed units.
“KWS has a range of multi-purpose hybrid maize varieties that are categorised as early and are suitable for both silage and crimped maize.
“They have been through a rigorous testing programme to ensure that they not only produce high-quality forage and crimped maize, but they also have favourable scores for grain yield, standing power and brackling.
“They will also have good ‘threshability’, which is essential when it comes to separating off the grain,” adds Mr Turner.
He highlights the dual-purpose KWS Reo and KWS Papageno as examples of varieties that can be used to produce forage or crimped maize. Crimped maize has a lot to offer in the right situation.
“Some units have benefited from late-season decisions to set aside some of their crop for crimped maize production.
“While it may not suit all farms, producers can find it useful for boosting ration starch content, particularly in a challenging year,” he adds.
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