For most farmers, the focus should be on silage quality to drive animal performance over the winter period and reduce concentrate requirement.

For others, the focus might be on harvesting as much bulk as possible, particularly if the material is for dry suckler cows.

However, while cutting a heavier yield of grass silage will make it more cost-effective per tonne ensiled, generally speaking it will reduce the feed quality.

Grass silage with a high level of stem will also reduce cattle intake, therefore animal performance will suffer unless supplemented with concentrates. There is, therefore, a balance to be struck between silage quality and yield.

Following these 10 steps when harvesting silage should help to increase forage quality for winter feeding.

Cut at the correct stage

To maximise feed value, grass should be mowed once the seed head starts to emerge, or as close to this time as weather will permit. Delaying the cutting date beyond this point will have an effect on feed value.

For every week that cutting date is delayed once the seed head starts to emerge, feed value will drop by around three to four units in D-value, the equivalent of 1kg of concentrate.

Also, to avoid cutting grass with high levels of residual nitrogen (which can lead to a bad fermentation), work on the rule of the thumb that a grass sward will use two units of nitrogen per day. Therefore, if you applied 100 units of nitrogen, the sward will be safe to cut 50 days after applying fertiliser.

If concerned about nitrogen in the crop, wilt the grass to over 30% dry matter, or alternatively use an additive to encourage desirable bugs in the fermentation process.

Mow and harvest grass in the afternoon

Mowing is best carried out in the afternoon when grass sugars are at their peak.

Mowing grass early in the morning can increase the level of nutrient loss, especially water-soluble carbohydrates, if the sward has any form of dew or moisture present.

The same principles apply when harvesting grass. Where possible, always start lifting silage in the afternoon.

Rapid wilt

To increase dry matter, spreading the grass within one hour of mowing is recommended, especially for heavy crops of grass. Spreading will increase the wilting effect, which will help improve fermentation and feed value.

Wet silage can lead to poor fermentation, high ammonia levels and, therefore, low palatability when offered to livestock.

The 24-hour wilt

There is little benefit in leaving grass lying for more than 24 hours before lifting and ensiling.

Wilting beyond 24 hours has little effect on feed value and if grass is too dry it increases the chance of losses (eg from leaf shatter) during harvesting.

The aim should be to get grass to between 25% and 30% dry matter as quickly as possible, to minimise silage effluent production and ensure a stable fermentation.

Chop length

Grass should be chopped to around 6in, which is the width of a cow’s muzzle. Leaving grass unchopped makes it harder to ensile as it creates more air pockets in the pit.

Long silage will also slow down cattle intakes, which will reduce performance. However, chopping too fine is not ideal either as it can pass through the animal without being fully digested. Short grass may require straw to be fed in the diet to slow the rate of digestion.

Take out surplus grazing

Silage time is a good opportunity to get your grazing rotation back on track. If you have too much grass ahead of livestock that is going to turn to seed and stem before it can be grazed, mow these fields and take them out as silage with the main crop.

This grass can be ensiled in the pit, or baled.

Bales can be easily marked and stacked before feeding to priority cattle this winter, or during a grazing shortage later in the year.

Filling the pit

Grass should be spread evenly across the pit when ensiling so that it can be rolled properly, expelling air.

When rolling the pit, the weight of the machine buck-raking grass will only be effective at expelling air to a depth of 30cm below the tyres.

Therefore, poor technique when buck-raking can cause poor fermentation, especially along the shoulders of the pit, increasing the amount of waste silage.

Seal the pit as quickly as possible

Having spent time filling the pit correctly, you should then plan to get the cover on as quickly as possible.

Covering the pit quickly will prevent air from getting back into the grass and help to start the fermentation process.

Stacking bales

If you work with baled silage, make sure you stack bales on a level surface that can catch any potential effluent.

As long as bales are well made and tightly packed, they can be stacked on their side or end without any risk of sagging.

Wrapping bales close to the stacking site reduces the likelihood of damage to plastic.

Mark the bales in terms of sward quality if you wish to target silage for specific cattle groups during the winter.

Safety

Remember advice on farm safety. Silage time is a period of high activity, with machinery moving in fields and farmyards. A busy farmyard is a dangerous farmyard. Make sure children are supervised if they are in the yard or fields.

Also, make sure that all machinery is in proper working order and has all guards present. You might know of a potential problem with a machine, but a family member or neighbour helping out might not.