The potential for tight supplies and volatile prices of certain bought-in feeds due to the effects of Covid-19 and other factors, has made it important for livestock farmers to make the best silage possible this season, a Scottish livestock specialist has said.

Alan Smith, of animal nutrition and forage preservation company, Volac, the ripple effects of Covid-19 had already impacted on the availability of feeds such as brewers grains, as beer consumption in pubs has halted.

On top of this, currency fluctuations and this season’s reduced plantings of winter cereals on UK farms, could also affect the feed market, he suggested.

Against this background, he believed it prudent for farms to meet as much of their livestock’s energy and protein requirements as possible from home-produced forage and silage. The aim is to help insulate farms against feed uncertainty, he added.

“Grass growth has been good in many areas,” says Mr Smith. “It’s now a case of preserving as much of its quality as possible.

“Practices such as cutting at the correct growth stage, wilting correctly, conserving with a proven additive and using top-level clamp management are all key areas to concentrate on – not just for first-cut silage, but subsequent cuts as well.”

As an example, Mr Smith said cutting grass before heading becomes even more important because digestibility falls by 0.5 D units a day once it starts heading, and a reduction of 3.6 D units requires an extra 1.5 kg of concentrate to be fed to a dairy cow per day.

Second-cut grass needs particularly careful monitoring because it goes to head faster than first-cut, he pointed out.

“Similarly, don’t be tempted to cut grass too low in an effort to gain extra bulk. The sward base is lower in digestibility, plus it contains undesirable microbes that will interfere with silage preservation. And make sure grass is wilted correctly,” he stressed.

“Wilting down to 28-32% dry matter is the optimum, because this both minimises nutrient losses in the field and in effluent. But it is important to wilt rapidly. The longer it’s wilted, the more sugar and protein will be broken down before it’s ensiled.

“Wilting time can be reduced by tedding grass to 100% ground cover promptly after cutting. If you do this, it’s possible to reach 30% DM in a day if conditions are good. However, take care not to over-wilt summer-cut grass, such as second cut. It tends to be lighter than first-cut and loses moisture faster in the hotter weather.

“At harvest, improve the preservation with a proven additive. As well as producing a more efficient fermentation, Ecosyl has been shown to increase digestibility by an average of 3 D units over untreated silage in trials, and preserve more true protein. It has also been shown to halve dry matter losses compared with an untreated fermentation,” he added.

When it came to filling the clamp, Mr Smith said clamps shouldn’t be filled in a wedge shape, as is commonly done, because this is difficult to consolidate properly – which risks air getting in, compromising the fermentation and triggering losses from heating. Instead, fill in horizontal layers no more than six inches deep, he advised, and ensure you roll it with enough weight.

“Grass at 30% DM needs 25% of its weight coming into the clamp per hour to be rolling it to compact it properly. So, 100 tonnes per hour needs 25 tonnes of machinery constantly rolling the clamp.

“By producing the best silage you can over the season, it puts you in a much stronger position,” he said.

Photo: Alan Smith with silage