BALED SILAGE is still the most economical way of conserving grass on many units, despite recent hikes in plastic wrap prices adding 40p a bale to wrapping costs.

Raymond Jones of the Institute of Grassland and Environmental Research, Aber<00AD>ystwyth, says film prices have already increased 30% on last year, with further increases of about 10% expected in the next few months.

 “The first thing to do is ensure wrap supplies are bought as soon as possible to guarantee supplies and price,” he explains. “Then, producers should look at the cost of producing baled silage and decide whether it is the best method for them. Particularly on hill units where only one or two fields are conserved at a time, baling silage will still be the best option. For these units clamp silage isn”t a good option as they have to constantly open and close clamps as they cut silage through the season.”

 Key issues for consideration include the value of the product in the bale. Whether or not bale silage is cost-effective depends on the quality of the silage being conserved. “It costs as much to wrap bad silage as to wrap good silage.”

“For the hill producer traditionally making more mature bale silage the value of the silage will probably be about 10 a bale. The cost of wrapping this bale when six layers of wrap are used will, this year, be about 2 – that”s one-fifth the value of the bale of silage.

 “But when better quality silage is made, with a metabolisable energy content of about 11.5MJ/kg DM at 30% dry matter, the value of the bale is about 20. In this case the cost of the wrap is only one tenth the value of the silage, making it much more cost-effective.”

It is simply a matter of cutting a bit earlier to improve silage quality and ensure wrap is used more efficiently, he says. “When better quality silage is made there may well be fewer bales an acre, but you need fewer bales to provide the same feed value, so it balances out.”

 And producers tempted to invest in clamps to lower silage costs should think twice. “Losses are more than three times higher in clamps than in bales. When silage is baled about 8% will be lost between baling and feeding, but with clamps losses are about 25%. In terms of overall feed value, baled silage is always more cost-effective,” explains Mr Jones.

Sausage-skin type silage storage options, such as Ag Bags, offer an alternative way of conserving grass. “But when you go to this type of storage you lose the flexibility which baled silage offers. Baled silage means you can make as much or as little as you want at a time. Sausage-skin type systems mean you have to cut it all at once and fill the sausage.”

Another cost cutting measure which may tempt some producers will be reducing the number of layers of wrap each bale receives. But this will jeopardise silage quality and cut the feed value of each bale.

 “Cutting back from six layers to four will cut wrap costs to about 1.40 a bale, but losses will nearly double to about 15%. With poorer quality silage, reducing the number of layers from four to two is definitely not an option,” he suggests.

 Bale transport and storage are other areas of improving the economy of wrapped silage, as several key points can increase wrap benefits. “The first point is to wrap bales at the stack site, not before transport. This lowers the risk of bales being ripped or damaged in transport and cuts the chances of silage quality being compromised by mould.

 “The second storage tip is to limit bird damage to stacked bales and this is best done by netting stacks to keep birds off. Finally, bales should be stacked no more than three high to ensure the lowest bales aren”t squeezed too much as this can also result in silage spoilage.”

 Higher film prices may also lead some producers to seek out cheaper film from alternative suppliers, but Mr Jones says this will probably be a false economy too. “Its best to stick with the normal brand and supplier as the back up service will be known and hopefully reliable.”

Producers ensiling other forages, such as red clover or peas in round bales should beware of reducing the amount of wrap used, he adds. These crops are particularly high value and have stiffer stalks, so are more likely to damage the wrap than grass silage might.

jonathan.long@rbi.co.uk