Plan ahead to unlock maximum energy from your grass silage

Farmers are being encouraged to take advantage of high milk and beef prices by maximising the energy potential of every blade of grass this silage season.

Lientjie Colahan, forage technical support at Lallemand Animal Nutrition, says now is a prime opportunity to focus on production from forage while prices are high.

To unlock the full potential in your silage, Mrs Colahan recommends carrying out pre-cut testing to understand grass quality and optimal cutting timing, paying close attention to the wilting process, and using a crop- and condition-specific inoculant to minimise losses during ensiling.

“Taking steps to ensure silage is as energy-rich as possible helps farmers to improve silage intakes, achieve greater herd productivity and boost bottom lines,” says Mrs Colahan.

Assessing fields for readiness is a crucial place to start, she explains.

“Firstly, check fields over for issues such as molehills and roll the field to reduce soil contamination, then take a grass sample to determine whether that field is ready for cutting.”

Mrs Colahan recommends grass sampling around a week before planned cutting.

“Farmers can collect the grass themselves - walk the field in a W shape, taking samples at the height you plan to cut it,” she explains.

“The worst thing you can do is go through the gate, grab five handfuls of grass, and send it away – that won’t be representative of the whole field.”

Once grass analysis results are available, the key parameters to pay attention to are dry matter (DM), free nitrates, sugar as a percentage of DM, and neutral detergent fibre (NDF) [see box-out for optimal values].

Once the results give the green light for cutting, Mrs Colahan says the wilting process is vital.

“As a general rule of thumb, in good conditions the dry matter will increase by a rate of 1% per hour,” she explains.

“This is somewhat of a movable feast - as DM values in cut grass are always changing – however, the DM results from your pre-cut test will give you a rough guide on how many hours you will need to wilt your grass to get the ideal value of 30% in the clamp.”

She says tedding will speed up this process, especially if done in the first two hours after the grass is mown.

“You can assess the DM of tedded grass by rolling it into a ball and squeezing it to see how much moisture comes out,” adds Mrs Colahan.

“If juice runs from the grass easily, then it’s 20-25% DM, but if the ball retains its shape, no juice comes out and it’s sticky, then that’s 25-35% DM and good to go.”

Lastly, Mrs Colahan recommends the use of a crop- and condition-specific inoculant to reduce losses throughout the silage-making process.

“The specific combination of bacteria and enzymes in our inoculants works to combat the challenges associated with different weather conditions,” she explains.

“These formulations break down forage fibre into sugars, preserving silage faster, preventing heating and spoilage - in spite of challenging conditions - and boosting digestibility, which translates to more energy for your cows.

“Every single blade of grass has cost you something already, so it’s vital to make the most of it with good silage-making and the right inoculant.”

BOX-OUT – Grass analysis values explained

The optimal values for cutting are:

• Dry matter (DM) – 18% at mowing, 30% for clamping, and 35-45% for baling
• Free nitrates – less than 1,000 mg/kg fresh weight because high nitrogen levels will buffer the crop and prevent efficient fermentation
• Sugar as a percentage of DM – more than 15% in the dry matter, or more than 3% if results are reported on a fresh weight basis
• Neutral detergent fibre (NDF) – 38-40%