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A simple switch from multiple sheets of traditional black plastic to a single sheet high oxygen barrier (HOB) silage film could reduce silage waste.... How ‘high oxygen barrier’ silage film can benefit farmers

• Reduce silage waste by over 40%

• Single sheet reduces plastic usage

• 7:1 return on investment possible

A simple switch from multiple sheets of traditional black plastic to a single sheet high oxygen barrier (HOB) silage film could reduce silage waste. At a time when livestock producers are using more home-grown feeds, the approach could deliver significant productivity and environmental benefits – reducing waste from 15% to 5%, say experts.

“We’re seeing significant reductions in silage waste and improvements in feed quality across the UK with HOB films and this is supported by comprehensive trials across Europe,” says Tim Brewer of silage film specialists Silostop Agri.

One study of over 50 individual pieces of work had shown a reduction in waste of 42% in the top layers of clamps sealed with HOB film compared to clamps sealed with standard polyethylene film, adds Mr Brewer.

Better quality

“The proportion of silage judged to inedible by livestock was also reduced with material stored under the HOB film compared with the standard film covering system and the aerobic stability of the uppermost layer of silage under the HOB film was much greater too.

“These results correlate with work carried out at the INRA Research Centre in France where HOB film gave a total silage loss of just 7% compared to over 15% with traditional black polyethylene film.”

Silage density was similar for both, but the total amount of silage DM removed for feeding was 17% higher with the HOB material, reflecting lower losses during the storage period, says Mr Brewer.

“Covering ensiled forage maize with a single layer thin HOB film has been shown to give large reductions in primary energy and greenhouse gas production compared to the normal practice of covering clamps with two layers of much thicker standard film.

“Work in the Netherlands has shown the total weight of plastic used in a 40m long by 12m wide clamp using standard film to be 241.5kg whereas with an HOB film it was only 43.4kg – just 18% of the standard film weight.

In terms of primary energy needed to produce the film at 78.1 MJ kg film this was 18.9 GJ for the standard film and 3.39 GJ for the HOB. This means it takes less than 20% of the energy to produce HOB film than it does to produce to standard polyethylene.

“At a time when everybody needs to produce their home-grown forages as efficiently as possible whilst limiting any harmful effects on the environment, HOB films have an awful lot going for them.”

Good investment

Jim Juby of Horizon Seeds, says modern HOB films make the ensiling process quicker and more reliable – and also deliver a significant return on investment.

“While use of thicker clamp plastics and clingfilm under conventional black Polyethylene has helped ensure good preservation of silage in recent years, many producers are increasingly concerned about the use of such materials.

“Using cling films and true oxygen barrier films can reduce wastage and ensure more of the forage energy clamped is available for milk or livestock production.

“Used properly, surface spoilage is virtually eliminated and top-layer shrinkage losses are reduced considerably with such an approach which means as well as being able to fed your cows better quality silage, you’re actually feeding more of it.

“All told, we believe that for every £1 spent on a HOB film such as Silostop Max, for example, you’ll get up to £7 of extra silage as a result.”

Clamp management

To make best use of such films, producers need to pay attention to consolidation of material in the clamp and keeping the top layer of forage as even as possible, he says.

“It’s easy to underestimate the speed at which material will enter the clamp but you need to match the speed of material entering the clamp with enough equipment to ensure all material is consolidated properly.

“It’s important, therefore, to make sure you have enough tractors consolidating fresh material as it arrives. It’s a false economy to have high work rates in the field that then lead to clamp management being compromised.

“The rule of thumb is that you want 25% of the number of tonnes being delivered into the clamp per hour as weight consolidating the silage. If a 16t trailer arrives every 10 minutes that’s 100t/hr, you will need another tractor alongside the buck rake.”