Focus now on maximising both the quantity and quality of remaining grass silage cuts as a contingency against another wet spring delaying next year’s turnout, dairy farmers are being urged.
According to Ecosyl silage scientist, Dr Mark Leggett, although making enough silage to last the winter is the first goal, the wet spring in 2024 provided a stark reminder of the importance of conserving some extra.
However, if ensiling bulk is prioritised over quality, he says it could leave cows milking off silage with inferior nutritional value, in the event of another delayed turnout. That will be disastrous if this coincides with peak lactation of spring-calving cows, so it is important to balance both quantity and quality, he points out.
You can compensate for low silage stocks or poorer silage with bought-in feed,” says Dr Leggett, “but you have to ask yourself whether this stacks up financially?
“Purchased feeds are important, but homegrown silage should be providing milking cows with as much of their energy and protein needs as possible. And dry cows over winter need good nutrition too.
Even in well-made grass silage, dry matter (DM) losses in clamps typically run at about 10%, but can easily be higher. More importantly, it is the most nutritious parts of the DM that are lost first. So the DM remaining will also be less able to support production of milk.
To help, Dr Leggett highlights four common ways in which losses in silage quantity or quality can occur:
1. Cutting grass after heading
Younger grass is typically higher in protein and energy, says Dr Leggett, but too often silage is made from grass that has already headed, by which time digestibility is falling by about 0.5 D units a day. “By one week post-heading, each cow will need around 1.5 kgs/day of extra concentrate to make up for this digestibility shortfall, in order to produce the same milk yield. So make sure grass is cut before it goes to head.”
2. Losses in the field
Wilting mown grass rapidly to the optimum %DM, which is typically 30% for clamped silage or drier for bales, so that it can be ensiled as soon as possible after cutting, is also crucial for minimising DM and quality losses, stresses Dr Leggett. Otherwise, he says, all the time that grass is still in the field it is losing sugar and protein.
3. Not using an additive
It is easy to think of an additive as a cost, admits Dr Leggett, but look instead at what it provides.
“A proven additive has been shown to cut silage DM losses by about half, which means more silage is available to feed. And the benefits don’t end there. Independent dairy cow trials have shown that feeding a range of silage crops preserved with Ecosyl additive boosted milk yield by an average of 1.2 litres/cow/day. With a tonne of silage typically feeding 25 cows for a day, this extra 1.2 litres over 25 cows equates to an extra 30 litres of milk produced per tonne of silage fed.”
4. Shortcutting silage consolidation, sealing or weighting
Failing to manage silage clamps correctly so that air gets in is another key way that DM and nutrients are wasted, says Dr Leggett. “Too many clamps still aren’t compacted enough to remove all the air, which risks losses from a poor fermentation and heating (aerobic spoilage) as unwanted microbes in the silage start to grow.
Grass of 30% DM loaded into a clamp at 100 tonnes/hour typically needs 25 tonnes of machinery rolling it to compact it properly. But the key point is that this 25 tonnes needs to be rolling it constantly. After rolling, make sure clamps are fully sealed and weighted to keep air out.
“As one of the cheapest feed sources available, making and conserving good silage is key to farming profitably,” he adds.
If you would like to learn more about planning ahead to avoid silage shortfalls, contact Dr Mark Leggett today.
Global Technical Manager – Forage
Volac International Limited
Tel: 01223 206239
Mobile: 07989 659744
E-mail: mark.leggett@volac.com