Continuing our exploration of Volac’s new Cut to Clamp initiative, which is aimed at helping producers insulate businesses against milk and feed price volatility by making consistently better silage, we examine the last three steps.
The first three steps of Cut to Clamp – cutting, wilting and harvesting – are all about capturing maximum feed value from grass and preparing it for conservation, says Volac silage microbiologist Philip Jones.
The next three steps – treating, clamping and feeding – are all about ensuring you preserve as much feed value as possible, so it is available for cows in the final ration.
Mr Jones says: “By doing this, you are ensuring you get the best possible return on the huge asset of your home-produced grass and hopefully reduce requirements for bought-in feed.” Independent silage consultant Dr David Davies agrees.
He says: “By making high quality silage, more of the animal’s nutrient requirements will be fulfilled from silage.
“This will reduce costs of milk production, reduce concentrate input and maintain a healthier rumen, therefore reducing metabolic disease. All in all, it makes profitable milk production far more likely.”
If you are aiming for high quality silage, there is no question that using a silage additive can help significantly, says Dr Davies.
He says: “Do not think of a silage additive as solving all your management issues. It is there to improve fermentation and quality, but you still need to do your bit.
“There are lots of additives in the industry, so seek independent advice and ask for independent trial results to highlight animal performance benefits. You want to spend on an additive which will improve animal performance.” Philip Jones echoes this.
He says: “By applying a proven additive at this stage, you are putting yourself in greater control of the fermentation process.
“To improve fermentation, you want to ensure maximum numbers of beneficial bacteria are present, such as Lactobacillus plantarum, which produce mainly lactic acid from the crop’s sugar, so the pH drops rapidly to inhibit growth of undesirable bacteria and moulds. “Although fresh grass will contain some beneficial bacteria, they tend to be in low numbers and are not the best types for achieving a fast, efficient fermentation.
“A good inoculant should provide bacterial strains specially selected to be highly efficient at fermentation and can supply as many as one million beneficial bacteria per gram of forage treated when used correctly.
“However, do not just think of a silage additive as preserving forage. While the proven silage additive strain of Lactobacillus plantarum MTD/1 has been shown to preserve dry matter, it also goes much further than that.
“There are trials which show treating with MTD/1 also improves silage metabolisable energy, digestibility, animal dry matter intake and, most importantly, leads to higher milk yield. Across a range of forages, milk yield was improved by an average 1.2 litres/cow/day.”
There are many actions which can improve silage quality in the clamp and at feedout, both experts agree.
Mr Jones says: “Begin with a clean clamp and repair any cracks.”
Additionally, Dr Davies highlights one of the biggest issues as being silage density.
He says: “We are not consolidating enough because trailers are arriving at the clamp too quickly.
“If you trap too much air in the clamp when you ensile grass, you reduce fermentation quality and increase aerobic instability problems at feedout.
“You can only efficiently consolidate the top 15cm. You want to load silage into the clamp in even layers no more than 15cm deep, compact the layer and repeat. I know it is a challenge, but then rolling only once is often enough to achieve a target density of 250kg of DM/cu.metre.”
For machinery, Dr Davies advocates consolidation with a compacter rather than a tractor. He says: “With a full width compacter, you are rolling the whole width of the tractor, not just individual wheel widths. “Another thing we often see is clamp overfill.
As soon as we fill above the walls, silage density drops by 10%. If you go over the top of the walls, you should consider putting that silage into bales.”
Mr Jones says farmers should pay particular attention to consolidating clamp edges, which are more difficult to compress. Once fully consolidated, it is essential the clamp is sealed properly to prevent oxygen ingress during storage, he says.
Dr Davies adds: “For this, I view side sheets as essential. Ideally, use oxygen barrier film for the top and the walls, with a minimum overlap of preferably 1.5m. This will give you a much better seal than standard sheets, although you will still need a standard sheet over the top of the film. Finish off with plenty of weight to maximise the density of the vulnerable top area.”
Dr Davies says another key area to get right is the ramp: “Too many farmers cut the silage sheet too short. We should ensure at least 500mm of extra silage sheet at the front with gravel bags all around the edge to seal carbon dioxide in.
“If we allow carbon dioxide to fall out of the clamp, we create a vacuum, which sucks oxygen in.
“Ideally, every grass silage clamp should be sealed for a minimum of two months. During those two months, you reduce the yeast population which initiates aerobic spoilage and heating at feedout.”
When it comes to feedout, cleanliness is everything, Mr Jones and Dr Davies say.
Dr Davies says: “I like to see a clamp you could eat your dinner off the floor in front of.
In particular, mouldy silage in front leads to mould spores contaminating the exposed face, increasing the rate of aerobic spoilage.
“Spoiled silage, whether due to a poor fermentation or aerobic spoilage, will upset rumen fermentation. Do everything you can to avoid producing it. If you have it, discard it.
“Too much of it ends up getting mixed in with the good silage and has a disproportionately large negative effect.”
To take silage out of the clamp, Mr Jones urges the use of a shear grab.
He says: “This maintains a tidy, tight clamp face, which reduces air ingress, reducing risk of aerobic spoilage causing loss of nutrients, reduced palatability and potentially production of mycotoxins.
“For the same reasons, move across the face quickly to reduce the time silage is exposed, avoid pulling or cutting the top sheet back too far once the clamp is opened and keep the front edge of it weighted down.
“It is important to avoid pulling the sheet down over the clamp face itself during feedout.
This is because it creates a microclimate, which encourages yeasts and moulds, increasing risk of spoilage and heating.
“Remember to scrutinise your silage analysis. It will tell you how good a job you did last season and help pinpoint ways this year’s silage production can be improved.”