The advantages of a higher bale density

A bale of grass with higher density has multiple advantages. Fewer bales are needed to store the same amount of crop, which reduces the costs for transport, storage and film. But the greatest advantage is higher forage quality.  

Round bales with a 10% higher density – a calculation example 

A farmer has to bale 1000 tons of grass a year with an average dry matter percentage of 40%. With an average bale weight of 650 kg, the total is 1539 bales a year. If the baler is set to a higher baling pressure, the bale density increases. So, if the bale density is 10% higher on average, what is the result? 

Baseline calculation example: 

Amount of grass per year  1000 tons 
Average dry matter content  40% 
Bale diameter   1.3 m 

Low density: 

Average bale weight  650 kg 
Number of bales   1539 bales 

10 % higher density: 

Average bale weight  715 kg 
Number of bales  1399 bales 

In the example above, a 10% higher bale density adds up to 140 fewer bales per year for the same volume of silage. And there’s no need to use any film for those 140 bales. With film costing €99 for a roll of 1500 metres, the cost to wrap 6 layers of film is €4.501. Film binding costs €1.27 per bale2. The total cost for film is €5.77 per bale. This delivers a total saving on film costs of €808 per year. Using less film also lowers the environmental impact.  

Savings on film costs: 

Wrapping 6 layers of film3  €4.50 
Binding 3 layers of film4  €1.27 
The total cost for film per bale is  €5.77 
Annual savings  €808 

And, additionally, there are 140 fewer bales that need to be transported from the field to the yard and you save storage space for 140 bales. This gives a total annual saving of € 526 on transport and storage costs.  

Savings on transport and storage costs: 

Transport costs per bale5  €1.67 
Storage costs per bale6   €2.09 
Total transport and storage costs per bale  €3.76 
Annual savings  €526 

Less air, more and better forage

10% more grass in the bale replaces air, which results in less oxygen in the bale. Less oxygen in the bale is beneficial for a fast and effective preservation process. Some amount of energy and dry matter is always lost in the bale because sugars are converted into water and CO2 by bacteria that need oxygen. The less oxygen there is in the bale, the faster this process will stop so more dry matter and energy will be retained in the silage. A higher bale density also benefits good shape retention as the bale is less likely to collapse. If a bale collapses, the layers of wrapping can slip apart and allow oxygen to enter the bales between the film layers. This will restart the decomposition process leading to losses of dry matter and energy.

At least 2% loss of dry matter 

2% less of dry matter thanks to a higher bale density is a realistic assumption according to Sjon de Leeuw of agricultural consultancy PPP-Agro. In practice, the difference may even be much higher. In the example of 1000 tons of grass a year with a dry matter content of 40%, the total amount of dry matter is 400 tons. A 2% loss means 8000 kg more dry matter retention per year. At an average cost of €0.16 per kg of dry matter, this converts to a saving of €1,280 per year. The costs of producing the grass, such as fertilising, mowing and baling, have already been made. If additional forage has to be bought, then the costs of the dry matter losses are even higher.  

Savings through better preservation: 

Total dry matter per year  400 tons 
Lower dry matter loss in %  2% 
Lower dry matter loss in kg  8000 kg 
Forage costs per kg of dry matter7  €0.16 
Annual savings  €1,280 

 

‘Homegrown concentrate’

The greatest benefits are to be found in terms of agronomy. Better forage quality improves bale palatability which leads to a higher feed intake by the cows. Optimal preservation also reduces mould in the bales and lowers the health risks. This in turn lowers the costs for veterinary care. Higher quality forage makes it easier to maintain good milk production levels in dairy cattle.  

Fewer other ingredients have to be added to the feed to compensate, so it is easier to formulate a balanced ration. A good bale equals ‘homegrown concentrate’. 

Slightly more fuel may be needed to create a higher bale density, and there will be more wear and tear on the machine. But, in the majority of cases the advantages will outweigh these disadvantages.  

Summary of benefits

Financial benefits (calculation example): 

Savings on film costs : €808 

Savings on transport and storage costs : €526 

Lower dry matter loss : €1,280 

Total annual savings : €2,614 

Agronomic benefits: 

  • Better forage palatability à higher feed intake 
  • Less mould in the bale à lower health risks  à lower costs veterinary care 
  • Possibly easier to maintain milk production levels due to better forage quality  
  • A better bale a ‘homegrown concentrate’

Also read: 

Fixed or variable bale chamber, which baler is best for me?

An important question to consider when purchasing a round baler or baler-wrapper: which type of bale chamber is most suitable? A fixed bale chamber with rollers, a variable bale chamber or a high density (HD) bale chamber that can produce a variable bale size? We have listed the advantages and disadvantages of each type of bale chamber below.  

Fixed bale chamber 

A fixed bale chamber is a round chamber with driven steel rollers that rotate and form a round bale. This is a reliable and easy method of producing a good bale. A fixed chamber baler will still produce a good bale even under difficult conditions, for example, with short or wet crops.  

When the bale chamber is being filled, the operator can use the full intake capacity. The baler will only start to compact the crop when the bale chamber is almost full. After being wrapped, the bale is ejected quickly to start forming another new bale. This means that a fixed chamber baler wrapper has a high capacity.  

Due to the maintenance-friendly, reliable concept and its user-friendliness and high capacity, an advantage of a fixed chamber baler is the low cost per bale. However, the disadvantage of a fixed bale chamber is that it offers no versatility in bale diameter, and compared with a variable bale chamber it is more difficult to create good bale density with drier crops such as hay and straw.  

Advantages: 

  • User-friendly method; easy to produce a good bale 
  • Extremely reliable concept with fixed rollers 
  • Good cost price per bale 
  • Low power requirement 
  • High capacity
  • Very suitable for short and wet autumn crops 

Disadvantages: 

  • Variable bale diameter not possible 
  • Less suitable for drier crops such as hay and straw compared with a variable bale chamber 
Bale chamber of a fixed chamber baler

Variable bale chamber  

A variable bale chamber has a combination of fixed rollers and adjustable belts that can increase the size of the chamber. Baling pressure is built up from the core until the desired diameter is reached. It is also possible to set whether the bale should have a soft or hard core and a soft or harder outer layer. The variable concept also has a better ability to produce a good bale with a high density from dry crops such as hay and straw.  

With a fixed bale chamber, the last bale to be formed might not have filled the bale chamber, so the final bale is not as firm. A variable bale chamber can compact and bind the bale well even if the chamber is not completely full.  

A variable bale chamber excels in versatility. It can produce bale silage with a diameter of 1.3 m in the morning, switch to forming smaller hay bales in the afternoon and finish with large straw bales in the evening. All possible with the same machine. 

A variable bale chamber is easy to use but demands a little more experience to produce the perfect bale. Especially in wet conditions, it can be more difficult to produce perfect bales.  

Advantages:

  • Variable bale size possible, from small bales for horses to large straw bales, for example
  • A larger bale size can save money
  • Well-compressed bales from start to finish
  • Variable density from core to outer layer possible
  • More suitable for dry crops such as hay and straw
  • Exceptionally good cost price per bale
  • Low power requirement#

Disadvantages: 

  • The operator will need a little more experience to produce perfect bales 
  • Less suitable for extremely wet autumn crops  
Bale chamber of a variable chamber baler

Variable HD bale chamber

n 2022, KUHN introduced a variable high density (HD) baler-wrapper: the VBP 7100 series. This model combines the advantages of a fixed and variable bale chamber in one machine. It can bale extremely wet crops in the same way as fixed bale chamber, but it can also bale hay and straw with an extremely high bale density. The intake is designed to fill the bale chamber quickly in the same way as a fixed bale chamber. The bales are also ejected at the same speed as a fixed chamber thanks to a special bale chamber concept with two tension arms. This allows the tailgate to open and close quickly, and the belts are immediately tensioned ready to start forming a new bale. This innovative technology means the machine can easily create perfect bales in all conditions.  

An HD baler-wrapper can form bales with extremely high densities. As a high bale density contains a higher volume of crop, high forage quality and lower transport costs are guaranteed. The heavy-duty construction of the bale chamber makes the machine extremely robust. The machine is over-dimensioned, so if a standard bale density is used, the machine’s service life will be extended further.  

However, the price of a baler-wrapper with a variable HD bale chamber is higher than a model with a standard bale chamber. A larger tractor is also needed to utilise the high capacity of this heavier machine.    

Advantages:

  • Combines a standard fixed bale chamber and a variable bale chamber in one machine: 
  • Variable chamber enables variable bale size 
  • Innovative technology makes creating a good bale shape easy 
  • Suitable for short and wet autumn crops  
  • The variable chamber is also extremely suitable for dry crops 
  • High capacity  
  • Heavy-duty construction 
  • High bale density 
  • High forage quality  
  • Lower transport costs  
  • Extended machine service life if used for standard bale density 

Disadvantages: 

  • Higher investment
  • Larger tractor required compared with a fixed or standard variable bale chamber
Bale chamber of a high-density baler

Also read: 

    • How does KUHN make a good bale? 
    • Save costs with a larger bale diameter  
    • The advantages of a higher bale density 

Costs savings thanks to a larger bale diameter

A baler-wrapper with a fixed bale chamber produces round bales of approximately 1.3 m in diameter. A baler-wrapper with a variable bale chamber can bale and wrap bales up to 1.6 m in diameter. This flexibility can be extremely useful, and a larger bale diameter can result in a lower cost per ton of forage. 

A round bale with a larger diameter: a calculation example

Take a bale of 1.3 m in diameter and 1.2 m wide that is bound with three effective layers of film, then wrapped with six layers of film. The three effective layers of film binding cost €1.27 with the KUHN TWIN-reel system. This calculation is based on standard wrapping film rolls of 1500 metres that cost €99 each. The six wrapping layers cost a total of €4.50 for film. This adds up to a total cost per bale of €5.77 for film.  

If the same calculation is made for bales with a diameter of 1.45 m, the costs for film binding are €1.38 and the six layers of film for wrapping are €5.37 per bale. This brings the total cost of binding and wrapping a bale to €6.75. This is an increase of 17% compared with the 1.3 m diameter bale. However, in this case the volume of crop in one bale is higher. A 1.3 m bale converts to 1593 litres, while a bale of 1.45 m in diameter has a volume of 1982 litres: that is 24% more crop per bale. If you calculate the costs of film per cubic metre, the result is €3.62 and € 3.41 per m3 of crop respectively. That represents a saving of 6 %. A bale of 1.6 m in diameter has a volume of no less than 2413 litres. So, the savings are even higher! In total, 13 % lower costs for film per m3. However, in practice it is more difficult to transport bales of 1.6 m and they can be quite heavy.  

Calculation example 1.45 / 1.6 m bale diameter compared with 1.3 m

Bale diameter   Bale volume  Increase in bale volume compared with 1.3 m  Film used per bale  Film costs per m3  Bale handling costs  Output 
1.3 m  1.59 m3           
1.45 m  1.98 m3  + 24%  + 17%  – 6%  – 20%  + 3% 
1.6 m  2.41 m3  + 51%  + 31%  – 13%  – 34%  + 4% 

Table 1: Calculation example difference 1.45 / 1.60 m bale diameter compared with 1.3 m bale diameter  

Save film and time  

Let’s take a farmer who produces 2000 silage bales with a diameter of 1.3 m per year as an example. If this farmer decides to produce 1.45 m diameter bales using a variable baler-wrapper, the same volume of silage will fit into approximately 1600 bales. That converts to 400 bales fewer a year.  

The total savings on film for this farmer are €688 a year.  

An additional benefit is 400 fewer bales that need to be loaded, transported and stacked, plus the baler operator can stop 400 fewer times a year to bind and eject a bale. And as less film is used, the total number of times the film must be changed on the binder and wrapper is significantly lower.  

Advantages of a larger bale diameter: 

  • Saves on net and film costs 
  • Using less net and film reduces the time spent on changing net and film 
  • Fewer stops to bind and eject bales 
  • Fewer bales to load, transport and stack 

Also read: 

Calculate the quantity of wrapping film required for the coming season

The new grass season is just around the corner. As an owner of a baler-wrapper combination or a bale wrapper, you would like to know in advance how much wrapping film you will need and how much it will cost. That way, you can stock up in advance so you don’t miss out during the season. And just as important: buy the film at the best possible price. Did you know that you can easily calculate this with the KUHN Film Calculator?

How the film calculator works

The film calculator can be used for round and square bales. Enter some data such as the bale dimensions, the desired number of film layers and the current film price. You will immediately see the estimated quantity of film required and a cost indication. You can also download this overview as a PDF.

Use the KUHN Film Calculator and be prepared for the wrapping season!

Calculator

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Opening round silage bales: net versus film

Which bales are faster to open: net bound bales or film bound bales? To find this out we took up the silage bale opening challenge!

Film bound bales easier and faster to open

We opened a round grass bale bound with net and one bound with film. The outcome is clear: the film bound bale could be opened way easier and faster, without loss of forage due to it staying in the net. Moreover, a film-on-film bale has only one residual product which makes waste management more efficient.

Curious how we conduced the test? Watch the video:

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