Timing plays a vital role in making quality silage. Moisture, maturity, chop length, kernel processing, packing, and covering all determine how the crop will ferment and how much feed value is preserved.
The decisions made during harvest have an impact on feed quality and livestock performance in months to come. Chopping too early can result in excessive moisture and a greater risk of seepage or undesirable fermentation. Conversely, waiting too long can result in too little moisture for proper packing and fermentation. Conditions can change quickly, once harvest begins, monitor the crop throughout the day and adjust harvest practices if needed.
Know When the Crop is Ready
Crop maturity and moisture should determine when chopping begins. Appropriate target moisture levels vary depending on the preferred storage system being used. For corn silage, whole-plant moisture or dry matter is one of the most important harvest indicators. Target moisture for corn silage depends on storage system. For bunkers, piles, or stacks a general rule of thumb is 65-70% moisture. Silage bags offer more flexible management, allowing for a wider range of moisture levels consisting of roughly 60-70% moisture. Corn silage in conventional upright silos typically performs best with 60-65% moisture. Oxygen-limiting silos can generally be managed at lower moisture levels, typical recommendations for corn silage ranging from 50-60% moisture.
Don’t start chopping just because the neighbors have. Hybrid, planting date, field conditions, and growing conditions affect plant maturity. Checking moisture before harvest and continuing throughout chopping can help ensure proper moisture levels are reached to maximize feed quality. Measuring moisture rather than estimating using visual appearance or kernel milkline provides a more accurate representation of moisture content in the crop.
Ultimately, conditions in the field should determine when the chopper starts.
Prepare Before Chopping Starts
A smooth and successful harvest starts well before chopping begins. Take the time to examine the chopper, making sure that knives, the shear bar, rollers, and kernel processor are adjusted properly and in good working condition.
Hauling capacity also deserves special consideration. A high-capacity chopper can get ahead of trucks or wagons if there aren’t enough available. Harvest efficiency suffers when trucks have to wait in the field or at the pile. Alternatively, if the packing tractor can’t keep up with incoming loads, feed may sit too long before being properly packed.
Storage area should be prepared before harvest begins. Plastic, oxygen-barrier, and enough weight for covering the pile or bunker should be available. Planning ahead of time can help prevent last minute scrambling and help maximize feed quality.
Pay Attention to Chop Quality
Once chopping begins, continually monitor material coming out of the chopper and make any adjustments when necessary.
Chop length is essential in maintaining an appropriate balance between effective fiber and the ability to tightly pack silage. It also can affect ration structure and processing. The ideal length varies depending on the crop, moisture, and feeding system. For corn silage, a theoretical length of cut is 3/8 to ½ inch is commonly recommended for unprocessed corn and about ¾ inch for processed corn.
In the case of corn silage, kernel processing provides additional consideration. Kernels should be processed so starch is available to livestock rather than passing through undigested. Regularly check processed corn silage throughout harvest, especially when crop conditions may change. Harvest conditions can change during the day. A crop that was at appropriate moisture in the morning may be notably different by the afternoon. Warm, dry, or windy conditions can exacerbate changes in crop conditions.
Don’t Overlook Packing
Chopping the crop is only half the job. Good packing is the other half and is essential for removing oxygen and creating an anaerobic environment essential for proper fermentation.
Spread silage in thin, uniform layers to maximize packing density and minimize trapped oxygen. Thick layers are more difficult to pack, increasing the risk of air pockets, heating, mold, and spoilage. Additionally, enough passes should be made to achieve good density to preserve nutrients and feed value for livestock. A general rule of thumb is to provide approximately 800 pounds of packing weight for every ton of silage delivered per hour. For instance, if 50 tons of silage are delivered per hour, approximately 40,000 pounds of packing weight would be needed to achieve appropriate packing density.
The goal isn’t to simply get trucks loaded and unloaded as quickly as possible; the crop needs to be spread and packed properly before the next load arrives. Good packing can help prevent feed losses later.
Cover and Seal Silage Quickly
Once the pile or bunker is finished, don’t delay covering it. Pay close attention to the edges, seams, and corners where air can easily seep into the pile. Make sure covering is adequately secured and inspected regularly for damage. A poorly sealed or uncovered pile can result in dry matter losses. Even under ideal moisture conditions, estimated dry matter losses occurring during filling, storage, and feedout can range from 16-23% for covered bunkers, 9-14% for bags, and 11-19% for upright silos. However, actual losses can vary with management. Nutrient losses as a result of poorly covered piles can erase all the hard work and investment of a well-harvested and well-packed pile. Ensuring silage piles are properly covered improves return on investment and can help reduce unnecessary costs associated with feed waste.
Conclusion
There is no way to control everything during silage harvest. However, good preparation can help producers respond quickly when challenges arise, helping to preserve feed value and investment. Stay focused on factors that can be controlled: harvest moisture, maintenance of chopping and processing equipment, keep material moving efficiently, and cover silage quickly after packing.
Make sure to take the time to monitor crop conditions and make harvest adjustments as needed.
