There is enough energy in a hectare of fresh forage maize to support around 30,000 litres of milk production.
But decisions at harvest can have a huge impact on how much of this energy is actually preserved in the silage, according to Volac’s Peter Smith
“There’s only one chance to get maize harvest and preservation right,” he says, adding that it is easy to underestimate how much milk can come from maize and the losses in its feed value that can occur during storage.
“Typical losses are around 15% of the maize dry matter ensiled,” explains Mr Smith. “But they can be much higher.
“The most obvious loss occurs when maize silage heats up, due to the growth of yeasts and moulds. But losses from poor fermentation can typically be 8% or potentially much more.”
He stresses that good maize preservation needs a multi-step approach.
Producers should start by harvesting maize at the correct time and way. “Harvest when the whole plant is at between 30% and 33% dry matter and chop it to a length between 1.5cm and 2cm. Avoid cutting the cut the crop too low.”
Following this advice will not only optimise nutrient content but will also allow for better crop preservation. “High dry matters and long chop lengths make it more difficult to squeeze the air out the clamped forage,” he says.
Using an additive can also aid preservation. “Look for a dual-purpose additive – one that controls heating and improves fermentation.”
Mr Smith says that Ecocool applies two strains of beneficial bacteria – one shown to produce a rapid fermentation, and one that inhibits yeasts and moulds. It has been shown to reduce dry matter losses and delay heating.
“With maize silage dry matter losses normally being around 15%, covering both potential problems like this is important,” he explains.
“It’s also important to consolidate the crop thoroughly and seal it well –to starve spoilage organisms of oxygen and to aid fermentation.
“Producers should look to consolidate to a density of 700kg of fresh maize per cubic metre. Ideally fill the clamp in horizontal layers that are no more than 15cm deep.
“And once air is out, don’t let it back in again. As well as a top sheet to cover the whole clamp, use side sheets all the way to the floor that provide an overlap, of between one and two metres, on top of a cling film-type sheet that covers the crop.”