There has been some considerable interest surrounding multi-cut grass silage systems, promoting more frequent cutting, but it might not always be successful in Scotland, according to those in know.

While farmers and contractors attending a recent series of meetings in South-west Scotland organised by Lallemand Animal Nutrition agreed that the objective of cutting grass at a younger stage and at more frequent intervals was correct, the practicalities of doing this in reasonable ensiling conditions were seen as particularly challenging.

Csaba Adamik, Lallemand regional business manager accepted the region presents specific challenges, but at the same time said an alternative could be arranged.

“In South-west Scotland the high level of rainfall, overcast and damp conditions mean it can be very difficult to get a clear weather window where the grass can wilt sufficiently. Very often, farmers make high quality grass silage of very low dry matter that constantly slips in the clamp which creates a huge challenge at feed out and with clamp management.

“Low dry matter, low fibre, high oil, short-chopped grass with minimal friction capacity is more prone to slippage, especially when clamps are filled too quickly in a Dorset wedge style and when clamps are overfilled. We commonly see clamps filled well above the bank walls.

“Over-compacting such grass will add to the problem and will pose challenges throughout the winter feeding season. This year has been particularly difficult with constant slippage seen on many farms across Scotland. Leaving first cuts to be a bit more mature seems to reduce this issue but will reduce feed quality.”

Roy Eastlake, Lallemand technical support manager said the objective of cutting grass at the optimum growth stage to ensure a high quality product had to be right. He argues that if you grow maize or wholecrop, harvest is timed around harvesting to produce an optimum quality feed. As grass is the mainstay of most dairy systems he advises that the same focus on quality is needed but the approach needs to be practical.

“The pay back can be considerable,” he told delegates. “If you are feeding 12kgDM of silage per day for a 220-day winter and can increase energy content by 1MJ/kgDM by cutting at the optimum stage, the extra energy will be enough to produce an extra 500 litres from forage over the winter. This will allow a saving of 225kg of concentrates. At £250/t this is worth £56/cow.

“So the challenge is how to produce high quality grass silage when the climate isn’t necessarily suited to taking a very early first cut. We believe the solution is what we called opti-cut as opposed to the more generic multi-cut.”

He added that while standard multi-cut focusses on taking the first cut as early as possible and then cutting at regular intervals to allow five or six cuts in the season, the opticut system is based on cutting and ensiling grass at the ideal growth stage compatible with the circumstances of the farm. This takes into account location and climate conditions, storage capacity and feeding system rather than just saying cut grass more often per season.

“While a major objective will always be to harvest sufficient grass silage for the farm’s requirements, this is combined with achieving the maximum quality that can be produced within the constraints of the farm," he said.

The process starts by sitting down with the farmer, the agronomist and most importantly the contractor and plan ahead for the whole of the silage season. The aim is to calculate the quantity of silage required from the grass platform and the quality necessary to maximise forage utilisation and reduce purchased feed costs within the total forage mix available on the farm.

Once a target first cut date has been set, plans are agreed with the contractor regarding the details of harvesting and clamping the crop to achieve the target dry matter and quality of grass required so everyone buys into the approach. Fertiliser applications and grass varieties and mixtures are discussed for the targeted cutting interval with input from the farm’s agronomist.

Assessing grass quality in the lead up to harvest is crucial to ensure it is harvested at the optimum stage. “At Lallemand Animal Nutrition we offer a free pre-cut grass testing service for our customers,” Csaba Adamik explains.

“This means the farmer has information on the fresh grass dry matter and NDF levels which provides the essential data to focus on how the quality of the crop changes, to predict the optimum cutting stage and date and determining practical decisions such as how often to ted the crop.

“Choice of inoculant is also crucial to ensure a rapid initial pH drop to preserve the harvested nutrients and then ensure the clamp remains stable once opened,” he continues.

“Analysing pre-cut grass samples for sugar and protein content as well as nitrogen levels enables us to target the correct Magniva Platinum crop and condition specific inoculant to aid a rapid fermentation and reduce dry matter losses, while ensuring the aerobic stability of the clamp at feed out.

“While typical multi-cut systems may not apply in Scotland, the opti-cut approach can deliver many of the benefits while reducing much of the risk.”