Growing and preserving enough quality silage to enable his farm to be self-sufficient during the winter is key to the success of Lenahowe farm on Orkney, where Paul and Fiona Ross run 100 Simmental and Salers sucklers alongside a flock of 135 breeding ewes. Keen to reduce the farm’s winter feed bill, and to minimise reliance on bought-in feed, Paul has recently looked to new ways of improving silage quality.
Farming on Orkney presents several key challenges, not least of which is coping with the prevailing climate. "Surprising as it may seem, we don't actually get too much really wet weather," Paul describes. In fact, the average rainfall on Orkney is lower than many parts of the mainland.
"What we do get however, are consistently high winds which can make it more difficult to grow crops with considerable losses of barley due to shedding. However, Orkney can grow grass really well in the short growing season.”
Paul’s farming system is designed to make the farm as self-sufficient as possible. “We supply fattened beef cattle to Scotbeef and McIntosh Donald’s abattoirs at 18-24 months from a medium input system, with the beef herd run at a modest stocking density. The cows are often housed for seven months of the year so it is vital that we produce as much high quality silage as possible to see the cows through to the end of winter,” Paul explains.
“Farming on Orkney makes it more expensive to buy inputs, with the additional ferry and freight costs significantly increasing commodity prices,” Paul adds. “We therefore aim to produce as much of our own winter feed as possible.”
In order to reduce his reliance on bought-in feed, Paul grows 40 acres of barley. In the last four years part of crop has been treated with urea and Maxmom which raises the protein content by up to three percent over Propcorn which is the more traditional method.
“In a normal year we can produce enough forage for the winter, but last year's challenging conditions made it difficult to produce enough feed to see the cows through to the spring. We aim to produce silage with a dry matter of 27-30%, but last year only achieved 21%. That meant we had to buy in extra feed and had to sell fattening animals earlier than usual and at a less-than-ideal weight. All of these had a serious impact on the farm’s bottom line."
With the challenges he faces, Paul does not underestimate the importance of proper crop conservation. "Producing silage on Orkney is a balancing act between making top quality forage and making enough to last the entire winter,” Paul explains. “We do all we can to grow and harvest a decent crop, but ultimately the quality and quantity of grass harvested comes down to a series of factors which are out of our control,” he adds. "What we can control is how we store and preserve the silage once it has been collected."
In order to maximise the nutritional value of his farm's grass silage, Paul carried out a simple trial in 2012 to assess the effectiveness of different sheeting products on silage quality.
“We have traditionally used conventional black plastic sheeting on both of our silage clamps,” he describes. “But last year we covered half of one clamp with Silostop Orange sheeting which is claimed to be 100% airtight. When we came to feed out of that clamp, we found that the silage stored under the Silostop sheeting was perfectly preserved, while the grass under the conventional black plastic was covered in a dark layer of mould.
“I have no idea what bugs, moulds or toxins were in the spoiled silage, but I certainly wouldn’t want to feed it to the cattle.”
The layer of mould can be attributed to the fact that conventional black plastic can allow up to 400cm3 of oxygen to pass through one square metre of sheeting in 24 hours. “Under these aerobic conditions, yeasts, moulds and clostridial spores will cause significant spoilage in the upper layers of the silage,” she states.
By contrast, a higher grade of oxygen barrier sheeting will allow just 3cm3 of oxygen through, resulting in no wastage and a superior quality of silage.
“It is useful to remember that not all plastic sheets offer the same level of protection,” “Using a product which creates a reliable oxygen barrier will provide a more stable environment for fermentation and can reduce dry matter losses in the top 40cm of silage by as much as 27%. That can give significant cost savings for most livestock farms by avoiding the need to purchase replacement silage and reducing reliance on supplementary feeds.”
Following last year’s successful trial Paul has covered both of this year’s clamps with Silostop sheeting. He estimates that moving away from conventional black plastic will save approximately 20 tonnes of the farm’s 1,000 tonnes of grass silage to aerobic spoilage.
“At a conservative cost of £40 per tonne to replace any spoiled silage, the more expensive sheeting will easily pay for itself,” Paul concludes. “Having seen the difference between the two types of sheeting, I’d be reluctant to go back to using conventional black plastic.”
