Have a good silage strategy this summer

When making silage this summer, the three key objectives are a good yield, a clean, well preserved and palatable feed and optimum silage quality (DMD).

The final point – optimum quality – is an interesting one. Advice for silage making seems to always centre on silage quality. And yes, of course quality is important, but optimum silage quality will vary from farm to farm.

Indeed, it will even vary within a farm. For example, in a winter milking dairy herd, silage quality is paramount. A herd milking over the winter should be offered 75%+ DMD silage. Anything less and concentrates will be required to make up the nutritional deficit.

Moving down the silage quality ranks, suckling cows, finishing cattle and growing stock will all require silage that is over 70% DMD. Again, a shortfall in quality can be made up with concentrates, but that obviously comes at a cost.

But then there are groups further down the rankings again. Dry suckler cows and even dry dairy cows in good condition do not have a high energy requirement and can therefore make do with lesser-quality silage.

Restricting the level of high-quality silage given to these groups is also an option, but that’s not always possible on farms short in feed space and with no accurate way of measuring what is being fed.

On most farms, this coming winter there will be a high demand for high-quality silage, but at the same time, there will also be groups where lower-quality silage can be sufficient. This opens a window of opportunity to allow some crops to bulk up.

To properly manage this balance between quality and quantity, a simple strategy can be implemented.

The first step should be to focus on making enough of the high-quality feed. Determine what the highest quality silage you require on the farm is, and then calculate how much of this is required. Following this, calculate how much ground will need to be cut to meet this target, remembering that your yield per hectare is likely to be slightly less with higher quality.

The second part will be to determine how much of the lower-quality silage you will require. If you plan on making a buffer, this should be factored into this silage type. Crop yield per hectare for this lesser-quality silage will likely be higher.

Silage quality

Silage quality depends mainly on the maturity of the grass plant at harvesting. To maximise silage quality, the crop should be cut before the grass plant has fully headed out.

Silage quality (DMD) falls rapidly after the heading-out date – approximately 0.5 percentage points per day. In first-cut crop, the heading-out date will typically be between 20 and 30 May. For second and third cuts, it will depend on the growing time of the crop.

While the plant itself will determine much of the silage quality, other factors can help. For example, mow when the dew has evaporated off the grass and when the sugars are up in the plant.

Wilting will improve the dry matter percentage (DM%) of the crop, but the manner in which this is done will have the greatest bearing.

Grass in large rows (6m mowing width) is unlikely to wilt much. Rows containing 3m of grass will wilt somewhat in 24 hours, but will likely need 48 hours. Tedded grass will wilt quickly, and in fact shouldn’t usually be allowed wilt for longer than 24 hours.

Whether to use an additive will depend mainly on the grass sugars and also on nitrate levels. Sugars over 3% do not need an additive while sugars between 2% and 3%, plus elevated nitrate levels, will only need an additive if wilting is not possible. Sugars below 2% will usually benefit from an additive.

Finally, for good preservation, airtight conditions are essential. A chop length of between 1cm and 1.2cm promotes good compaction.

The pit should be rolled with a heavy machine quickly and a good-quality plastic cover should be used to seal the pit. When making bales, it is important to maximise the DM% of the crop to help maintain a dense and well-shaped bale. A slow tractor speed, the correct baler settings and finally, careful handling and storage of bales, are also important.