Bale advice all wrapped up

6 July 2001

Bale advice all wrapped up

By Hannah Velten

AMONG most big bale silage stacks there are usually some misshapen and mouldy examples which are consigned to the dump.

But some expert advice could prevent wasting the 0.5t of valuable feed contained in each bale.

Making quality baled silage begins with quality grass. Baling should not just be used for leftover grass at the end of the grazing season, but as a continuous part of pasture management, says Institute of Grassland and Environmental Research scientist Raymond Jones. "High quality bales are produced when grass is cut from pasture or silage aftermath regrowth before 50% of seed heads are showing. This means cutting often, generally in small areas to produce firm, high-density bales."

Advice on grass dry matter content for optimum quality bale silage varies. The range is between 25-35% DM after wilting for 24-36 hours, depending on the class of stock to be fed. Grass between 25-30% DM will retain its ball shape and not release any juice when rolled and squeezed in the hand for 30 seconds, says Pembrokeshire-based ADAS senior consultant George Brew.

Wet grass produces a misshapen bale and fails to ferment effectively, while drier material makes less dense and compacted bales that are prone to mould, he adds.

Rapidly wilted grass will also reduce bale handling costs. "Less bales to the acre will be made when water is removed from the swath, which substantially reduces contractor, wrap, transport and handling costs."

Mr Brew says preparation of the swath is crucial to produce a well-shaped bale. "Swath width should match the width of baler pick-up and be of an even depth to ensure flow of grass into the baler produces a uniform, well-compacted bale."

According to Mr Jones, applying one litre of biological inoculant to each bale will improve fermentation, increase animal performance and silage protein content. But it is a waste of money on anything less than high quality grass, he adds. "A fairly cheap, simple sprayer system will ensure an even application of inoculant through the bale. This can be achieved by attaching three nozzle jets evenly across the bar above the pick-up reel and installing a simple pump, attached to a barrel on the front of the tractor."

Tim Keady, researcher at the Agricultural Research Institute of Northern Ireland, emphasises the need to wrap bales at the site of storage. "Remove bales from the field to their final destination before wrapping because film can be damaged when moved.

"It is most important to wrap bales as soon as possible, preferably within an hour, to keep oxygen out and allow fermentation to begin," he adds.

But when bales are wrapped in the field and not transported within 3-4 hours, they should be left until the next day, says Mr Jones. "As fermentation begins gases are produced, blowing out the bale. When bales are moved at this stage they have a tendency to burst, producing pinholes in the film."

Effective wrapping is essential to prevent air entering the bale and causing yeasts and moulds. At least four layers of film are advised. But stemmy material, such as haylage, or silage with less than 25% DM needs six layers to prevent punctures or loss of seal due to bale distortion, says Mr Brew. Silage destined for valuable animals also needs six layers, says Dr Keady.

Problems can also occur when maintenance of the wrapping machine is neglected, says Mr Jones. "Rollers that pre-stretch wrap become covered in tack, which reduces their stretching ability, so they must be cleaned with white spirit every week."

Careful storage is the final part of successful big bale silage making. Mr Jones advises storing bales on sand or washed gravel to provide a soak away for leakages and prevent vermin from getting under bales. Any poison bait for controlling rodents should be placed around the site rather than in the stack, which can attract them to bales, adds Mr Brew.

John Donworth, a producer discussion group facilitator in Ireland advises placing the bales flat edge on the ground and keeping bales tightly packed. "Apart from being dangerous to remove, bales more than three high put pressure on bottom layers, causing bale distortion in wetter silages."

Mr Donworth says his group members often have bales damaged by crows, so they paint white crosses on, wrap and put netting over bales as a deterrent. &#42

BIG BALE SILAGE

&#8226 Use quality grass.

&#8226 Careful wrapping essential.

&#8226 Control against damage during storage.