Good maize silage to ease forage shortfalls

Attention to detail this autumn will get the best from winter feed

Ensiled maize could be particularly important this year – helping to offset low grass silage stocks caused by the summer drought and early opening of clamps.

The need for buffer feeding ahead of winter could make it important to employ extra vigilance to safeguard maize silage against losses this year, helping to stave off forage shortfalls, says Volac silage expert Peter Smith (right).

Other reasons are because of the high costs of supplementing low silage stocks with bought-in feeds, he says, and to capitalise on buoyant milk prices, with maize providing a cost-effective and high-energy homegrown forage.

In some areas, the drought has also impacted maize yields, says Mr Smith. At the same time, high fuel and fertiliser costs mean maize has cost more to grow this year, so protecting the crop in the clamp will be important to cover this extra investment

Avoiding losses

“In a normal year it may be possible to tolerate a few losses in maize silage. But with grass growth halted in many areas during the summer drought, any significant in-clamp losses in maize could be disastrous for overall winter silage stocks.

Even average losses in maize clamps equate to about one in every 10 trailer loads of dey matter being lost. Poor conservation can see this loss increase. “When spoilage occurs around the vulnerable top and shoulders of clamps, losses here can reach 50%.

“It’s not just the least nutritious parts of the dry matter that the microbes that cause maize silage losses feed on. It’s the nutritious sugars and starches. So not only is there less dry matter, anything remaining is lower in energy.”

Certain microbes can also reduce silage palatability and cause mycotoxins, adds Mr Smith. To help conserve maximum maize quality and nutrients, Mr Smith suggests some key dos and don’ts.

Do not leave maize harvest too late

It is easy to miss the ideal 30-33% DM content for harvesting maize, says Mr Smith, often because contractors cannot get to the farm in time. However, harvesting maize too dry makes it less digestible to the animal and more difficult to consolidate. Check your crop regularly so you can get your contractor on-farm at the ideal time, and remember modern maize varieties are often still green when ready to harvest. 

Do chop maize to the correct length

With maize so vulnerable to heating, chopping it to the correct length to aid squeezing out air from the clamp is crucial. Shorter chop lengths aid consolidation, especially if maize is dry, so consider chopping to 1.5-2.0cm, or down to 1.2cm if needed.

Resist the temptation to cut crops too low

Although it might be tempting to cut maize crops closer to the ground this year in search of extra bulk, do not do this. The stem base is low in digestibility and contains high numbers of undesirable microbes from soil, which interfere with preservation in the clamp.

Ensile with the correct type of additive

Although maize silage is prone to heating, this is not the only way DM and nutrients are lost.

Invisible losses from poor quality fermentations, caused by naturally-occurring inefficient fermentation bacteria on the crop, can account for half the overall DM losses, so it is important to target both problems with a dual-acting additive.

Dual-action additive Ecocool, containing the bacteria Lactobacillus plantarum MTD/1 and Lactobacillus buchneri PJB/1 enhances fermentation and can keep maize silage cool and stable for more than 10 days after removal from the clamp.

Consolidate and seal the clamp properly

At 30% DM, it typically requires about 25% of its weight arriving at the clamp per hour to consolidate it, so 100 tonnes per hour requires constant rolling by 25 tonnes, for example by a loading shovel plus a good-sized tractor.

Fill clamps in horizontal layers at no more than a 20 degree angle, and at most 10-15cm deep, for maximum benefit from compaction machinery. Filling in a wedge shape makes consolidation more difficult.

To minimise air ingress, clamp walls should be lined with polythene side sheets, and an oxygen barrier film which is sucked into the surface contours placed on top of the maize to create a good seal.

Pull side sheets over this with a minimum 1-2 metre overlap all around, followed by a polythene top sheet, then a protective woven sheet well-weighted with silage mats, touching tyres or bales. Finally, protect from rodents and birds.