An increasing number of producers are growing maize to make alternative feeds to add to TMR rations. So what does it involve and what are the benefits? We spoke to an agronomist to find out more.
TEXT WENDY SHORT
Maize silage has earned its reputation as ‘rocket fuel’ for dairy cows, but using the crop to make corn-cob mix and crimped-grain maize is gaining in popularity, as producers seek to increase home-grown energy feed production. Both feedstuffs offer several other benefits, according to KWS’ Andrew Cook.
Corn-cob mix (CCM) and crimped-grain maize (CGM) are widely fed to cattle in countries including France, Denmark and Germany, and the UK’s growing climate is suitable for their production.
“A growing number of producers, feeding TMR rations, are finding that CCM and CGM can help to reduce bought-in feed costs,” says Mr Cook, adding that both feeds have the potential to make a valuable contribution to the diet.
CCM offers an average starch content of between 45% and 55%, and an ME of 13MJ/kgDM, and average analysis for CGM shows starch levels of between 65% and 70%, with an ME of 14.5 MJ/kgDM.
“Both maize products contain high levels of bypass starch. They will require some specialist machinery to harvest, but many contractors have recognised the trend and responded by investing in the required kit,” says Mr Cook.
CCM comprises the ripe maize ear, which includes the grain, spindle and sheath. It is produced using a row-dependent maize header coupled to a forage harvester, and it can be preserved in a silage clamp, or in an ag-bag. It is highly palatable, with the cob sheath adding valuable ‘scratch factor’ to the ration. “And it will complement many milking rations and help to promote high dry-matter intakes,” he adds.
Corn-cob mix: crop requires high-grain-productivity potential
Correct varietal choice is important for a successful crop of CCM. “Varieties selected for this purpose should compact or semi-compact and have an FAO, or maturity rating, ranging between 150 and 210, as well as a high-grain-productivity potential.
“Due to the requirement of a ripe cob, so that it can be snapped off and the grain cracked, it is typically harvested three or four weeks later than a standard maize silage crop. But this factor can be mitigated by opting for an ultra-early variety, which will have a shorter growing season. This will help to keep harvest dates on track,” he explains.
“CCM offers flexibility because it can be made in cases when harvest is delayed for crops intended for silage. An additive is advisable and the stubble that it leaves behind can be mulched in at a later stage. This will improve soil organic matter levels.”
Another benefit of CCM is its low effluent risk and reduced storage requirement compared with conventional maize silage.
Crimped-grain maize (CGM) uses only the maize ear and is harvested using a conventional combine and a maize-picker header attachment. “It can be fed directly without processing, but most producers employ contractors to treat the material with crimper rollers, to expose the endosperm and save on drying costs,” says Mr Cook.
Typically harvested between three and four weeks later than conventional maize silage, cutting decisions will depend on the accumulated number of heat units throughout the season. The stover is left on the field, thereby improving land travel.
“CGM offers an excellent balancing feed for rations containing high levels of whole-crop cereals or grass silage,” he says. “Like CCM, it is extremely palatable as well as being beneficial for rumen health. It should be added at a maximum rate of 20% to TMRs due to its extremely high starch content. And, as always, rations should be balanced, particularly because at higher levels of inclusion it may carry a potential risk of acidosis. This illustrates its superb nutritional qualities.” Many of the properties and production principles for CCM also apply to CGM. “The latter analyses at between 65% and 70% dry matter and, like CCM, it carries a low risk of effluent,” says Mr Cook.
“Unlike varieties appropriate for CCM, however, CGM varieties should not be chosen from the ultra-early maturity category. This is due to the late target cutting date.
“Over-ripe crops can be prone to brackling. Brackling can occur in an over-ripe crop, when the top third of the stem buckles as the plant dries out and causes lodging. At the point when the grain is threshed from the cob. Crimped maize should be exposed to air for as short a time as possible, so the clamp should be filled rapidly and crop well consolidated in the clamp.” A high rating for standing power is another desirable trait for both CCM and CGM, again due to the slightly later harvesting date. Varieties for CGM should have a grain-to-stover ratio of more than 50% because this is an indication of good ‘threshability’.
“As purchased feed costs continue to impact dairy profitability, CCM and CRG have a lot to offer,” says Mr Cook. “Rapid advances in maize breeding have increased the appeal of these alternative feeds because maize can now be grown in parts of the country where achieving yield targets may have previously presented a challenge.”
Table 1: Typical maize crop feed analysis