Switching from entirely big bales to clamp silage involved a leap of faith for Shropshire farmer, Henry Roberts. But he took the opportunity to set up a system from scratch, putting best-practice
in place all the way through.

Shropshire farmer Henry Roberts, and his father before him, had been wedded to big bale silage for around 30 years, and when they weren’t making their own, they were contracting for neighbouring farmers.

Farming 140 dairy cows plus followers and 150 head of dairy cross beef at Pentre David in Hengoed, near Oswestry, Henry admits that every summer was taken over by silage making, leaving the team exhausted by the time 2,000 bales had been made and stored.

Winter feeding continued to take its toll on the team, and the herd’s production reflected the inevitable variations in quality which come with big bales. Both the milk quantity and quality varied from day to day, and the milk cheque went up and down in the same vein.

Production seemed to hover around 6,500 litres and the cows easily reached the limit of their intakes on the high dry matter bales.

But although the team knew that clamp silage would be better on many levels, they never found the opportunity to set up the system.

“The investment put us off to start with and the obvious place to build a clamp was where the big bales were stacked,” says Henry. “There were always bales left over so we would have had to move them and the next thing we knew we would be baling again.”

The argument in favour of clamp silage eventually became overwhelming and Henry and his father, Richard, finally constructed their clamp in spring 2017.   

“Dad made the decision that the farm should be set up so I could run it without him, and his approach, as always, was that we should do the job right,” he says.

In fact, tragedy struck later that year, when his father’s untimely and unexpected death saw Henry left running the farm on his own. By this time, the system was established for making clamp silage, in exactly the way his father had planned.

The new clamp was housed in a purpose-built, steel framed building with a concrete floor and concrete side panels. It measured 120 x 40 feet, and was 28 feet to the eaves.

By keeping it under cover, there would be no risk of entry by rainwater, nor pollution or waste through run-off from the clamp.

“We had talked to a lot of neighbours and some of them had told us that 40 feet was too wide, and we’d be bound to get some heating with such a wide face,” says Henry.

However, he and his father had read about preserving silage with Safesil; they could see it worked differently and more consistently than other additives on the market so were keen to give the product a try.

Bryn Thomas, area sales manager for Kelvin Cave, explained the benefits of the preservative which he was confident would give Henry and his father complete reassurance.

 “The Safesil preservatives contain the ingredients sodium benzoate and potassium sorbate which will actually eliminate the activity of moulds,” he explained. “It is this activity which causes silage to heat and, in the process, to lose feed value and palatability.”

Safesil also contains sodium nitrite which works by killing harmful bacteria. This helps achieve the rapid and clean fermentation which can be relied upon to stabilise the forage.

“I was completely confident that if Henry applied Safesil at the correct rate, he would have no heating at all in a 40-foot face. I was also confident the silage would be stable enough to put out for the beef, as he required, on just three days a week,” he says.

 Henry says he was also afraid of poor consolidation so went out of his way to compact the clamp well.

“I knew our silage contractor had a SilaPactor which would add weight to the compaction process, so I asked him to use it,” he says. “It’s done an excellent job; it’s left our silage face like a concrete wall and the forage is stone cold and smells so good, I honestly feel I could eat it!”

Also opting to double-sheet the silage using O2 Barrier 2in1, this single application product comprises a high-quality upper layer covering an oxygen-impermeable vacuum film.

“If you are using a cling-film type product, I don’t see the point in applying two separate sheets when you can apply it as just one process,” says Henry.  

Sealing the clamp is also important and Henry has been equally keen to do this job well.

“I would rather we did it properly ourselves than it was done in a hurry by a contractor,” he says.


Using side-sheeting with plenty of overlap, gravel bags are placed along the sides of the clamp.

“Side sheets are a fractional cost in the grand scheme of things. We have an entire winter’s worth of forage in there – I don’t want to throw any away,” he says.

And with netting and weighting to finish it off, it is well protected from damage and birds.

Clamp management at feed-out is undertaken with similar care, and a ProDig shear grab with a 1.7m blade was bought for the purpose.

He says: “This picks up 700kg in a full grab which is just enough for loading the wagon without too many trips, nor dropping too much weight on the augers.”

The resulting high-quality silage has led to a succession of benefits, not least of which has been the 500 litre per cow increase in milk, accompanied by a rise in milk quality and the price received per litre.

“I had been worried that changing from a long fibre silage to a chopped forage would send our milk quality down, but in fact the clamp silage quality has been so good that it’s had the opposite effect,” says Henry. 

The higher quality silage is also consumed in greater quantity, having lifted the ceiling on dry matter intakes.

“It means we’re getting more milk from forage and have been able to reduce the protein in the parlour cake,” he says. “Before, we fed 23% protein, but we have now dropped to 20% which saves £10 per tonne.”

Equally, the beef can be fed on just three days a week with no risk at all of the silage heating, while the dairy cow feed passage is swept up just once every week to 10 days.

Consumables for baling have also been saved, but even more valued is the saving in time during the summer.

“We can see what we have done is better because the cows are milking and looking better and the cake costs less,” says Henry. “I would not go back to big bales for the milking cows.

“We should have done this years ago, although, perhaps, if we had, we wouldn’t have done the job as well as we’ve be able to do it today.” 


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