- Do you have to cover silage?
Silage is preserved because it undergoes fermentation while in storage - think wine or sauerkraut. To maintain the nutritive and energy value of forage and to keep it free of molds and harmful bacteria, the fermentation process needs to produce an abundance of lactic acid, and the bacteria that accomplish this are anaerobic. If your silage isn’t sealed and covered, the conditions for maintaining a high quality fermentation won’t be met and you’re likely to experience significant loss to spoilage as well as loss of nutrients and energy.
Silage covers also protect silage from exposure to the sun and rain, either of which can present risks, either to the quality of the finished silage or to the local environment, in the case of seepage. Uncontained seepage from silage represents a major environmental hazard. Covering silages to prevent rain from soaking into (and through) them is always worth the cost and trouble.
- Why is my silage black?
High quality silage will be anywhere in the range between golden brown and greenish yellow. Black or dark brown silage is usually a sign that things got too hot during the first stage of the fermentation sequence. Often, you’ll be able to detect an odor of tobacco or caramelized sugar. In severe cases, it will simply smell burnt. This kind of heat damage could be a sign that the forage was too dry at ensiling, or it could indicate that the forage was poorly compacted, ensiled too slowly, or even inadequately chopped. In any of these cases, too much oxygen is available during the early stages of fermentation, which allows the internal temperature to climb and delays the beneficial anaerobic phase when desirable lactic acid fermentation should take over. When this kind of overheating happens, proteins in the forage become denatured, making them less digestible. While this kind of silage may still sometimes be palatable, even moderately damaged silage like this should be disposed of, as it has a high potential for molding.
- How long does silage last?
High quality, well-sealed silage could potentially last for several years, depending on the storage method, although from a practical standpoint, silage should generally be fed out within a year. If silage is carefully sealed to maintain an anaerobic environment, silage could potentially last for years. The real issue is your level of confidence that the seal is 100% and has not incurred any damage - since the damage can be slow and difficult to detect.
Whatever your storage method is, all silage will start to spoil once it is exposed to air. Once a bunker or pit has been unsealed, a portion of the exposed face needs to be carefully removed (typically a minimum of 6 inches) and fed out each day. Any portions of the exposed silage face that aren’t removed will begin to rapidly deteriorate and bacteria and mold growth will begin to take hold with the arrival of oxygen.
- Does rain ruin silage?
Once cut, forage exposed to rain will obviously become wetter, making it more difficult to reach DM (dry matter) targets in a timely manner. Rain also leaches sugars from the plant tissues, robbing the potential ensilage of energy for fermentation. If the forage is exposed to too much rain, it could become altogether unsuitable for ensiling, since excessive loss of carbohydrates leaves bacteria very little to work with in the fermenting process.
If you’re caught in a sudden rainshower right as you’ve begun to chop for the day, it may be best to just turn around and hope for dry weather tomorrow. If you’re mid-field and the rain is light, you can try pulling out a handy rain gauge and calculating the amount of additional moisture you’ll be bringing in with your crop - with luck, you’ll be able to calculate when you should stop bringing damp forage to keep the overall DM for day at an acceptable level. Whether than means you quickly bring the harvesters back in mid-morning, or they run for the rest of the day, you’ll need to cover the clamp completely. Once it’s chopped and in the clamp, your priority is keeping out oxygen, and that means covering the clamp with an airtight cover that’s completely weighed down. Skimping on this step is a sure recipe for disaster, no matter how well you calculated your DM allowance.
- Is it worth it to weigh down a silage cover?
There is no question that covering a silage bunker, pile, or trench will save money in the end, by reducing spoilage, preserving valuable nutrients, and maintaining the digestibility, palatability, and safety of the feed. But is the heavy work of putting weights all over the top of a silage cover really worth the time and effort? In a word - Yes. Absolutely.
Since the whole purpose of covering silage is to eliminate the possibility of the silage being exposed to air, steps need to be taken to also eliminate air pockets that may pop up between the cover and the silage itself. Ideally, the cover will conform exactly to the surface of the silage pile, kind of like a vacuum packed piece of meat. Since it’s rarely (if ever) practical to vacuum pack silage, we have to do the best we can. Weights placed at frequent intervals across the top of the silage pile will help achieve that close fit. A common solution has been tires, parts of tires, slices of tires, etc. Sandbags or gravel bags are also popular. Let’s not kid ourselves - that’s no fun to deploy, but the ROI can be convincing. Say you have a single 40 x 100 foot bunker filled with corn silage - By properly covering and weighting that cover to minimize air pockets and keep it in place, you could potentially see a $2,000 improvement in usable yield.
- What does good silage smell like?
High quality silage is usually pale or honey brown or greenish yellow with an overall pleasant aroma but relatively little distinctive smell. This is because lactic acid, the prevalent acid in well-fermented silage, is nearly odorless. The vinegary aroma that many point to as a signal of good silage is actually associated with acetic acid. That triggers a bit of a conundrum, because high levels of acetic acid are associated with decreased intake and reduced milk production in dairy cattle, so a strong vinegar smell isn’t necessarily a good thing… right?
In fact, well-fermented silage should have both types of acids present, with a ratio of about 3:1 lactic to acetic. This is important, because when silage is ultimately opened for feeding, it’s the presence of acetic acid that maintains aerobic stability in the silage. Considering this, it’s reasonable to say that a mildly vinegar (acetic acid) smell is ideal, rather than absent or overpowering.
- How long should silage ferment before feeding?
The exact length of fermentation will vary, of course, by the type of crop, the ensiling technique, local weather conditions (exceptionally hot or cold, for example), and other tough-to-pinpoint considerations. Typically, a properly compacted and sealed silo should spend no more than 3 days in the aerobic stage, followed by a very brief transition period before the anaerobic bacteria take over and start the serious work of pumping out acid and lowering the pH. Typically, the fermenting process should be complete (stabilized) in about 3 weeks, but you should monitor pH changes before ringing the dinner bell. Silage should never be fed out before fermentation is complete.
- Are silage tarps hard to maintain?
High quality silage tarps are not difficult to maintain - in general, they require nothing more than regular inspections for tears, holes or excessive wear. Obviously, this can be managed most easily as they’re deployed at the start of the season and as they’re removed when the silo is finally emptied.
To make sure your silo covers last, make sure you’ve chosen the right material at the beginning. Look for a cover that’s durable, UV and weather resistant, flexible and lightweight enough to deploy easily. A layered construction with a white side and a black side adds even more protection.
- Is silage cheaper than hay?
It’s not really possible to say which is cheaper in any specific case, since the costs will depend on the livestock (Dairy cattle? Beef cattle? Horses?), the forage (alfalfa? barley? corn?), and other practical considerations, like whether you own the equipment or have to rent it, and even the storage options you have in place.
When stored under ideal conditions, both dry hay and silage could potentially last for several years, but even premium hay loses much of its vitamin content within the first few months of storage, while forage preserved through fermentation (silage) maintains its full nutrient profile as long as it remains protected from exposure to air. If you plan on feeding out your hay or silage each year as you put it up, this won’t necessarily be a big consideration, so many farmers look to weather patterns and storage challenges to make their final decision. Silage does need to be wilted briefly before ensiling, but it is much less dependent on a series of sunny days for success as hay, for example.
- What crops can be used for making silage?
Today, silage is most often made from grass crops, from cereals like corn and sorghum, and from legumes like clover, alfalfa, and vetch. Silage makes use of the entire green plant, not just the grain. Many other crops are also suitable for ensiling, such as potatoes, sugar beets, and even some plants considered weeds in many contexts. In some cases, weeds present unique possibilities during times when drought or high temperatures prevent more traditional crops from producing. Of course, many of those same weeds also have some undesirable traits, and care needs to be taken to avoid problems.
