Advice For Dairy Farmers On Handling Dry Silages

handling dry silages

Many dairy farmers will aim to achieve silages that are between  25-30% dry matter (DM). But with challenging weather early on in the grass growing season, 2021 samples, in a number of cases, have indicated silage is dry with an average of over 40% DM.

When dry matter is already so high in silage, it becomes crucial that consideration is taken on how to manage the overall DM within total mixed rations (TMR). This will avoid issues with palatability and the knock-on effects of this.

Benefits of adding moisture

For those who are seeing silage with high DM values, adding moisture, such as water, into a TMR is recommended. This can often help prevent dairy cows sorting the ration, which can lead to issues like subacute ruminal acidosis (SARA) and poor milk quality.  

For farmers looking at this option as a solution, consideration should be given to how much water needs to be added to a TMR diet, as this can impact palatability of the diet and intakes. An understanding of the dry matter of all dry ingredients is needed to accurately measure the volume of water required to achieve a TMR with a total optimal DM of 40%. Aim for the following amounts of water:

TMR dry matter before water is added (%)

Added water requirement to reach optimal TMR dry matter of 40% (Litres/head)

 

60

16.7

55

13.6

50

10

45

4

Table 1: Water calculations

Before adding water to a TMR, it’s important the potential issues associated with this process are understood so that the necessary precautions can be taken:

  • If water isn’t left to soak-in, sorting of rations could be a problem as there isn’t enough time for the water to penetrate the feeds before being eaten
  • Keep an eye on potential ‘balling’ of concentrates, caused by faulty blades on a mixer wagon or insufficient mixing time. This will mean the mix is denser than a standard TMR, putting pressure on machinery parts
  • Adding a preservative or mould-inhibitor, such as Selco TMR, at the time of mixing can help reduce further heating and waste. Adding a liquid feed, such as molasses, together with water is more effective than adding water alone to help reduce sorting.

Compact feeding

Another option to aid palatability when DM is high is compact feeding. This is a form of feeding that provides cows with feed that has usually been soaked for longer than a standard diet to reduce the likelihood of sorting.

This technique has been shown to increase daily milk yield by an average of 1.6 litres/cow and achieve even dung, butterfat and rumination levels among cows.

If going down this route, add 1 litre of water to 1kg concentrates and soak the feed overnight. This will mean it’s less likely to heat up than if water is added to the forages, reducing the risk of spoilage.

Top tip: Adequate fibre levels are needed in the diet for compact feeding to work, and diets must not have a high level of fermentable starch prior to adding water, because fermentation will increase and lead to potential issues with acidosis.

Pay attention to potential contamination risks

Dry silage could provide a source of mycotoxin contamination and poor dry matter intakes. This is because very dry silages are difficult to consolidate, especially at the sides of the clamp. This allows air to remain in the clamp and mould to grow, causing mild or severe mycotoxin issues. 

Pay attention to good hygiene to reduce mycotoxin contamination risk. Using a shear grab will help to keep the face of the silage clamp clean while also reducing heating, spoilage and losses at feed out. Aim to move across the pit as fast as possible as this reduces exposure of the silage. Half grabs may have to be taken to achieve this. If issues are seen in cows, consider feeding a mycotoxin binder.