Mixed weather and variable silage quality put flexible grass management in focus

Dairy farmers are being urged to be adaptable in their cutting strategy and make the most of any weather windows as grass crops respond to changing conditions.

Lientjie Colahan, forage technical support at Lallemand Animal Nutrition, explains that the spell of warmer weather at the end of May, followed by rain and rising temperatures, has encouraged grass to move from vegetative into reproductive growth.

"At this stage, the plant begins to put more energy into stem development,” says Mrs Colahan.

“As stem length increases, so do neutral detergent fibre (NDF) and lignin levels, which reduces digestibility and can lower the energy value of the crop, leading to poorer quality silage.”

To limit this loss in quality, she advises taking any realistic cutting opportunity when conditions allow to help reset the plant and encourage leafy regrowth for subsequent cuts.

“Even if conditions aren’t ideal, taking a crop as soon as possible if the grass has recently bolted will help stimulate vegetative growth again,” she explains.

“This encourages the plant to grow leaves rather than stems and will improve the quality of later cuts.”

However, she says farmers also need to focus on preserving as much quality in the crop as possible once it has been cut, which can be more challenging when grass is mature and stemmy.

“These crops pose a double challenge because they can be lower in readily available sugars, the main fuel for fermentation and are often harder to consolidate effectively in the clamp, meaning oxygen can be left within the layers,” she says.

“If either of these things happen, fermentation can be slower and the risk of yeast and mould growth, heating and spoilage increases.”

Mrs Colahan adds that this makes inoculant choice and application particularly important this season.

“A crop- and condition-specific inoculant containing homofermentative and heterofermentative bacteria, alongside specific enzymes, can help accelerate fermentation, release sugars and improve aerobic stability at feed-out,” she says.

Mrs Colahan says each component plays a specific role in helping maintain the nutritional quality of the crop through to feed-out.

“The homofermentative bacteria make the most of the available sugars to produce lactic acid, helping to drive a rapid pH drop, while enzymes help make more sugars available from the crop,” she explains.

“Heterofermentative bacteria also use sugars but support aerobic stability by helping to inhibit yeasts and moulds, reducing the risk of heating and spoilage once the clamp is opened.

For more information, please visit www.lallemandanimalnutrition.com