Fresh forage contains microbes such as bacteria, yeasts and mould. It is a mixture of beneficial microbes, such as lactic acid forming bacteria and undesired microbes such as clostridia or moulds. Proliferation of microbes in silages initially leads to consumption of the oxygen trapped in the silage. Once all oxygen is consumed, growth of anaerobic lactate forming bacteria decreases the pH of the silage. This acidification results in stability of the silage.

If the balance between beneficial and undesirable microbes is disturbed or the amount of oxygen after harvesting is too high, this acidification process will slow down. This will create favourable conditions for the growth of yeasts, coliform bacteria, clostridia and moulds. These moulds can sometimes be recognized via visual inspection. The growth of these unfavourable microbes results in a bad smell and reduced palatability of the silage. This will ultimately lead to reduced nutritional value and palatability of the dairy ration.

Crop contamination with microorganisms occurs already on the field, but also before and during harvesting. Proliferation can either occur after ensiling, after opening of the silage (mainly at the cutting edge) or in the TMR once the silage is mixed into the dairy ration.

In case of grass silage:

• Aim at an optimal yield with a correct level of sugars
• Apply sufficient amounts of fertilizer at least 8 weeks before mowing.
• Avoid surface application of slurry within 10 weeks of mowing to reduce the risk of contamination with undesirable micro-organisms.
• Avoid that the dry matter level of grass silage is too high as a result of excessive wilting.

In case of corn silage:

• Harvest corn silage before it reaches the dough stage. The risk of fermentation increases once corn is cut matured.

There are a number of measures that can be taken at harvesting:

• Avoid contamination with soil as much as possible, as this can be a source of anaerobic bacteria.
• If the dry matter of a crop is above 30%, fine chopping makes it easier to exclude air once the crop is put into the silage bunk.

When the trenches are filled properly, reduced growth of aerobic micro-organisms will help to ensure subsequent stability of the silage:

• Ensure the silage storage space is clean, the surface is smooth, and the silo is not leaking before it is filled
• Organise harvesting in such a way that delayed filling of the silos can be avoided.
• Don’t harvest to much crop in a single session.
• Adapt the tractor weight and harvesting speed to ensure good compaction, the optimal packing density of a silage is around 240 kg/m3

After the crop has been harvested, there are two things that can be done to maintain quality of the silage while it is in the bunker. Firstly, reduce exposure to oxygen as much as possible. Secondly, stimulate the growth of beneficial bacteria that produce lactic acid:

• Apply plastic lining of the side walls of the silo.
• Ensure the silo is being sealed properly and as quickly as possible. Use plastic of at least 125 micron, cover with soil and/or tires.
• Use side sheers.
• Keep the clamp airtight, repair any damage caused by birds or rodents.
• Use long narrow silos instead of short wide ones, as this will allow a rapid rate of feeding once the silage will be opened. The silage face should advance by at least 30 cm/day.
• Consider the use of inoculants or additives at harvesting. Use a dairy feed additive such as Fyvalet Silage in case of crops with a high dry matter content and relatively low levels of easily fermentable sugars. Use an additive such as Fyvalet Corn in case of crops with a high moisture content and/or high level of easily fermentable sugars. Both additives improve temperature stability of the silage. This ensures the silage lasts for as long as possible after opening the clamp.

Costs of grains, concentrate and compound feed are increasing, so the total feeding costs of dairy cows can be reduced by increasing the amount of silage in the ration. Next to that, intake of sufficient levels of fibre is essential to keep the dairy rumen healthy. Dairy cows should therefore have access to sufficient and fresh roughage in their ration for optimal performance and health and to ensure maximum income over feeding costs.

Formulating an optimal ration starts with analysing all silages available. The test results will not only help to formulate the ration correctly but they will also be a good reflection of how good forage and silage management has been.

• Cut the silage in such a way that the face of the silage remains smooth. This keeps the surface area as small as possible, allowing less penetration of air.
• Clear up loose material that is spilled onto the area in front of the cutting surface.
• Treat the cutting surface with Selko®-TMR in order to slow down the fermentation. Spray 0.25 liter of Selko-TMR per square meter cutting surface.
• Keep the sheeting close to the face.
• In case of leakage of air into the silo, growth of micro-organisms, particularly moulds, can occur at the top layer and the lateral sides of the silage. Spray 1 liter of Selko-TMR per square meter on the top layer and sides of the silage.
• Feed dairy cattle twice daily to reduce the period of time the TMR is being exposed to oxygen.
• Mix Selko-TMR into the dairy ration to reduce growth of micro-organisms.

The performance of a dairy cow during lactation is heavily impacted by the dry cow period and the transition to lactation. Once a dairy cow is 30 days into lactation, it is very difficult to improve her performance. The only tool remaining is the quality of the roughage. Silage management before and during harvesting, during the period of storage and at feeding can have a huge impact on the quality of the TMR fed to dairy cows. Excellent silage management can maximize dairy farm profitability and ensure sustainability of dairy farming.