Over the past week, there has been an increase in silage activity from farmers working on drier land. On heavier land, silage harvesting may still be two to three weeks away depending on the date silage ground was closed up and grass growth to date.

Making good-quality silage can be a difficult task. Cutting date is invariably reliant on good weather for harvesting a dry crop at the correct stage of plant maturity. With the improved weather of late, many farmers may opt to leave silage crops to bulk up over the next week before harvesting. The reason is to get as much grass harvested as possible.

Higher yields not only reduce the cost of making silage, but on farms that regularly deal with a six-month winter feeding period, it is important to have plenty of fodder in reserve. While it is important to maximise yield, it is still important to have an emphasis on silage quality.

Likewise in cutting date, if the weather presents an opportunity to get grass mowed and harvested during a dry spell, then it is an opportunity that should not be missed. The farm system will dictate what type of silage is required.

For a spring-calving herd that is selling weanlings in autumn, silage quality can be sacrificed slightly in favour of yield. Silage with a feed value of 66 to 68 DMD will generally suffice when feeding dry cows in good body condition. Thin cows will require higher-quality silage to increase body condition before calving, or else concentrates will have to be offered with average silage (66 DMD).

For autumn-calving herds and finishing herds, silage quality should be as high as possible and ideally 72 to 74 DMD or better. The higher the quality of silage, the higher the level of animal performance. Silage of this quality will help keep autumn cows milking without a reliance on concentrates as well as help get cows back in-calf. It will also reduce the level of concentrates required to finish cattle indoors. As a rule of thumb, 4 DMD units in silage quality are roughly the equivalent of 1kg of meal. Therefore, moving from 66 DMD to 74 DMD silage could help to cut out 2kg of meal from a weanling or store animal’s diet, which is a weekly saving of €3.36/head (taking meal at €240/t).

For 50 weanlings, this amounts to more than €2,000 in a 12-week feeding period.

Bulk

While cutting a heavier yield of grass silage will make it more cost-effective, generally speaking it will reduce the feed quality. However, you should remember that bulk isn’t everything.

Grass silage with a high level of stem will result in lower intakes from cattle when fed during the winter. It will also be harder to compact when ensiling, which can lead to a poor fermentation and higher levels of waste or spoilage.

Low intakes mean lower animal performance. Cows need to be housed in an adequate body condition in order to hold flesh. It will be difficult to gain body condition in thin cows and heifers if silage feed value is low at 60 DMD to 64 DMD.

Quality

It is still possible to make high-quality silage at yields of 10t to 12t per acre. Such yields are usually made from reseeded or well-managed ryegrass swards. With high-quality silage, there are more options for flexibility when it comes to feeding.

For instance, if you decide to push cattle for intensive finishing rather than storing and returning to grass, or decide to hold weanlings over winter due to low market prices this autumn, then you will be in a better position to do so if you have focused more on silage quality rather than quantity. Silage intakes will be higher on good silage and there will be less waste when fed out. If silage yields are low, then you may need to boost fodder reserves, with additional bales made from surplus grass, or focus on a bigger second cut.

Here we outline 10 steps to getting good-quality silage.

1. When to cut: Grass should be mowed as soon as the seed head starts to emerge, or as close to this time as weather will permit. For every week that cutting date is delayed once the seed head starts to emerge, feed value will drop by around 3 DMD units. Missing the chance to cut this week and waiting to next week means you need to feed weanlings an extra 1kg of meal/head/day to make up for the drop in feed value.

The merits of focussing on bulk and quality have already been outlined, but remember that the longer you leave the cutting date, the slower the grass regrowth after harvesting. This means you will have a lower yield or a later harvesting date for your second cut.

A late second cut can put grazing under pressure in late summer if you normally use silage ground for livestock grazing.

2. Mow grass in the afternoon: If you use a contractor, then this may not be an option. But if you can, ask for mowing to start in the afternoon. The reason for this is grass sugars are at their highest in the afternoon, as is grass dry matter. When mowing in the morning grass dew can still be present, and this increases nutrient loss, especially water soluble carbohydrates.

3. Spread within one hour of cutting: Spreading and rowing up grass adds costs, but if done properly in dry conditions, it will increase grass dry matter, which improves fermentation and feed value. Wet silage has a low palatability and can have a high ammonia level, which leads to a poor fermentation. Poorly fermented silage will heat and have high levels of spoilage when fed out to animals and at the pit face.

4. Limit wilting to 24 hours: There is little benefit in terms of feed value for leaving grass longer than 24 hours before lifting and ensiling. The longer you leave the sward lying, the drier it gets. With a very dry silage, there is an increased chance of leaf shatter (loss) when harvested.

5. Lift grass in the afternoon: As with mowing, lifting in the afternoon will avoid any dew and again grass sugars are at their peak. You may not have this option if you work with a contractor who is looking to complete the job before moving on to the next farm.

6. 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 leaves 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. Very short grass can upset the animal’s rumen and straw will then be required along with silage.

7. Bales from surplus grazing: Making bales from surplus grass on grazing ground will help with grass management. These bales can be easily marked and stacked before feeding to priority cattle this winter or during a grazing shortage later in the year.

This means you are targeting high-quality grass to finishing cattle every day whereas with pit silage there will be a variation in quality as you move across the pit face as well as move from top to bottom of the pit face.

8. Fill the pit evenly: Grass should be spread evenly across the pit when ensiling. 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. The machine should be constantly rolling the grass as the pit is being filled.

9. Do not over-roll: Once you have the pit filled, avoid rolling the grass again the next day. Starting to roll the grass again can create a vacuum effect that actually sucks air back into the pit.

10. 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 getting back into the grass and help to start the fermentation process.

Farm Safety

Silage time is a period of high activity, with machinery moving in fields and farmyards. Remember that a busy farmyard is a dangerous farmyard. Be careful during all tasks involved with silage harvesting and make sure any children are supervised if they are in the yard or fields. Also, make sure that all machinery is in proper working order and have all guards present.

You might know of a potential problem with a machine, but a family member or neighbour helping out might not.

The cost of silage

This is a topic that often generates debate among farmers. When you buy meal, you get a quote per tonne, so it is easy to know the value and compare it with other rations. When you make silage, the costs are split up between land bills, fertiliser bills and contractor bills.

Also, estimates of the fresh weight of silage in the field as opposed to what actually ends up in the pit can greatly differ.

Table 1 outlines some of the costs involved in producing silage. It also outlines the costs per tonne for different yields.

The example is based on silage made on rented land costing €180/acre spread over 200 days which is a cost of 90c/day. Silage ground was closed up for eight weeks. A contractor is employed for mowing, raking, lifting and ensiling. Fertiliser spread was three bags of 27-2.5-10 at €380/t along with 2000 gallons/acre of slurry.

The costs of producing first-cut silage varies from €19 to €28 depending on yield. Second-cut silage costs will vary depending on the growing period, yield and fertiliser rates applied.

A late first cut can lead to a late second cut and lower yield which increases the costs, despite lower fertiliser rates.

In summary, when it comes to silage, there is a compromise to be made between quality and quantity. Good silage is still cheaper than meal so there should be an emphasis on offering cattle the best grass possible during the grazing season and this should continue into the winter also with quality silage.