How to cut silage should be mastered by all breeders who want to prepare healthy fermented feed for lean seasons. It is not simply a matter of cutting fresh grass and wrapping it in silage film or placing it in an airtight container. There are several important steps and considerations for producing good silage that will genuinely support livestock health and productivity.
Beginners and experienced farmers alike should keep updating their knowledge of how to cut silage. The method currently in use may not be delivering the best possible results. New tools and techniques continue to emerge that can improve both convenience and the quality of the fermented feed produced.
Information on how to cut silage must also be accompanied by a solid understanding of the silage-making process as a whole. You also have to be selective when choosing your silage wrapper, prioritizing products that are resistant to punctures and tears and capable of protecting the silage from ultraviolet light exposure.
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How Cutting Technique Affects the Quality of Fermented Feed
Cutting silage is a critical part of feedstock management that directly determines the nutritional outcome of the preserved feed. For farms with large livestock numbers, reliable silage production during the growing season is essential to ensuring the animals receive adequate feed during the dry months when fresh grass is scarce.
How to cut silage encompasses cutting technique, timing, grass type selection, and chop length management. After applying the correct cutting approach, the subsequent stages of packing and storing the silage bales must be carried out as effectively as possible using quality silage film. The full silage fermentation process depends heavily on decisions made at the cutting stage.
The raw material for silage, fresh grass, undergoes fermentation and preservation through the activity of lactic acid bacteria and other specific microorganisms. Various studies have confirmed that the process from cutting and wilting through to preservation will directly affect the nutritional quality of the final feed. A wrong cutting method disrupts the microbial environment in the cut grass, which then compromises fermentation quality and reduces the feed value of the preserved silage.
Silage Cutting Checklist at a Glance
| Factor | Best Practice | What Happens If Ignored |
|---|---|---|
| Cutting Timing | Cut at early heading stage, do not delay | Dry matter drops by up to 3 percentage points per week of delay |
| Weather Conditions | Cut on sunny days after morning dew has dried | Lower water-soluble carbohydrate (sugar) content in the grass |
| Cutting Height | Leave 5 to 7 cm stubble above ground | Soil contamination increases, slowing fermentation and causing spoilage |
| Chop Length | Target 2.5 to 5 cm theoretical length of cut | Too long reduces packing density; too short reduces effective fiber for ruminants |
| Wilting Duration | 24 to 36 hours for round bale silage | Too wet reduces fermentation quality; too dry causes poor compaction |
| Livestock Adaptation | Adjust fiber and sugar content to livestock type | Mismatched nutrition reduces feed efficiency and animal performance |
Key Factors in How to Cut Silage
Pay Attention to Silage Cutting Time
Cut the grass promptly and do not delay the harvest once the optimal growth stage is reached. Research shows that silage quality decreases when cutting is postponed, with dry matter content dropping by up to 3 percentage points for each week of delay past the optimal harvest window.
For temperate regions in the Northern Hemisphere, this typically means monitoring pasture growth from May to June. In the Southern Hemisphere, including countries like Australia and New Zealand, the equivalent window falls between October and December. The correct cutting time is when seed heads are just beginning to emerge on the new growth, indicating peak nutritional content before the plant diverts energy from leaves into seed development.
Adapt the Cutting Method to Your Livestock
Finishing cattle require fermented feed with different fiber and energy profiles compared to young calves or lactating dairy cows. The cutting stage, particularly the timing and the maturity of the grass at harvest, will determine the balance between fiber and sugar in the silage. Consult with a feed nutrition specialist if needed to align your cutting method with the specific requirements of the livestock on your farm.
Cut on a Sunny Day After Morning Dew Has Dried
Grass cut on sunny days after morning dew has evaporated will have a higher water-soluble carbohydrate (sugar) content. Photosynthesis accumulates sugars in plant leaves throughout the day, so cutting in the mid-morning to early afternoon captures this peak. Sugar content in well-timed cuts can be up to 3% higher than grass cut in poor conditions. This higher sugar level feeds the lactic acid bacteria during fermentation, resulting in more stable and longer-lasting silage. When natural sugar content is low due to overcast conditions or species selection, adding molasses as a fermentation additive is an effective solution.
Keep the Grass Free from Soil Contamination
Soil contamination is one of the most damaging factors in silage production. Cutting too close to the ground introduces soil bacteria, particularly clostridia and other spoilage organisms, into the silage mass. These compete with beneficial lactic acid bacteria and lead to butyric acid fermentation, which degrades the silage, produces foul odors, and significantly reduces feed palatability and nutritional value. Always set your mower to leave a stubble height of at least 5 to 7 cm above the ground.
Wilting Stage After Cutting
The correct cutting process must be followed by an adequate wilting period. After mowing, allow the cut grass to lie in the field for 24 to 36 hours to wilt down to the target dry matter level. For round bale silage, the target dry matter is typically between 30 and 40%. After reaching the right wilt level, the grass should be wrapped promptly in high-quality silage film to begin the anaerobic fermentation stage.
Wilting too long increases the risk of rain damage and over-drying, which produces poorly compacted bales with insufficient moisture for good fermentation. Wilting for too short a time leaves the forage too wet, which can lead to clostridial fermentation, effluent production, and nutrient loss. Matching wilting time to the weather forecast on the day of cutting is an important practical skill for any bale silage producer.
The wilting process may face challenges in unpredictable weather. Having the right equipment, including quality wrapping machinery and reliable bale net wrap, ensures you can respond quickly when conditions are favorable and wrap bales without delay.
Beyond mastering the technicalities of how to cut silage, breeders are encouraged to be selective when working with silage film suppliers. The quality of your wrapping material directly protects the investment made at every earlier stage of production.
Frequently Asked Questions about How to Cut Silage
Q: When is the best time to cut grass for silage?
The best time to cut grass for silage is at the early heading stage, just as seed heads are beginning to emerge on the dominant grass species in the pasture. At this stage, the plant has accumulated high levels of water-soluble carbohydrates (sugars) in its leaves while still maintaining good digestibility and fiber structure. Cutting too early means lower yield and potentially lower dry matter. Cutting too late means higher fiber and lower digestibility, as energy shifts into seed development. In the Northern Hemisphere, this typically falls in May to June. In the Southern Hemisphere, the equivalent window is October to December.
Q: What chop length is recommended when cutting silage?
The theoretical length of cut (TLC) for most silage operations is between 2.5 and 5 cm. Shorter chop lengths improve packing density and help exclude air more effectively, which supports better fermentation. However, extremely short chop lengths reduce the effective fiber fraction of the silage, which can negatively affect rumen function in cattle. Dairy farmers often target the shorter end of this range to maximize packing density in bunker silos, while beef producers may use slightly longer lengths. Your target chop length should also be matched to the harvesting and packing equipment available on your farm.
Q: Why is it important to cut silage on a sunny day?
Grass accumulates water-soluble carbohydrates (sugars) through photosynthesis during daylight hours. Cutting on a sunny day, after morning dew has evaporated, captures grass at a point of relatively high sugar content. These sugars serve as the substrate for lactic acid bacteria during fermentation. Higher sugar content in the cut grass leads to faster pH drop during fermentation, which produces more stable silage that is less prone to spoilage. In cloudy or wet conditions where sugar content is lower, adding a fermentation additive such as molasses can compensate and improve fermentation quality.
Q: How long should grass be wilted before wrapping for bale silage?
For round bale silage, the standard wilting period is 24 to 36 hours under good drying conditions, targeting a dry matter content of between 30 and 40%. At this level, the forage is moist enough to compact well and support lactic acid fermentation, but dry enough to minimize effluent production and clostridial activity. The exact wilting time needed will vary depending on the weather, the thickness of the swath, and the moisture content of the grass at cutting. Checking dry matter with a simple grab-and-squeeze test or a portable dry matter meter helps you make the right call in the field.
Q: What happens if silage is contaminated with soil during cutting?
Soil contamination introduces unwanted bacteria, particularly clostridia, into the silage. These anaerobic bacteria compete with lactic acid bacteria and can dominate the fermentation if conditions allow. The result is butyric acid fermentation, which produces a foul-smelling silage with dramatically reduced palatability and feed value. Contaminated silage can also increase the risk of listeriosis in cattle if Listeria monocytogenes is present in the soil. Always cut at a stubble height of 5 to 7 cm to minimise soil pickup, and avoid cutting after heavy rain when soil splash onto the lower leaves is at its highest.
This article was last reviewed and updated by the Silopak Editorial Team on May 20, 2026. Our team periodically revisits published content to ensure accuracy, relevance, and alignment with current best practices in livestock feed management and silage preservation.
