Good management practices are required for storing forage as either dry hay or as silage or balage (individually wrapped bales, in plastic tubes or chopped into silo bags). In general, putting up silage or haylage will result in less forage yield loss and higher nutritive value than when stored as dry hay. Curing forage for hay requires more drying time, resulting in greater chances for rain damage, and more losses occur when the forage is handled in a drier condition. Since silage and haylage is preserved at a higher moisture content, it is faster to get to a proper dry matter content for safe preservation than it is to make dry hay. Proper dry matter content for chopping haylage can often be achieved within 24 hours as compared with three to five days for dry hay, depending on the conditions.
The following practices will improve the success of preserving forage in a good condition:
MAXIMIZE EXPOSURE TO SUNLIGHT because it is the most important weather factor that speeds drying. Make the windrows as wide as possible for maximum forage surface area exposure to the sunlight. The swath width should be at least 70% of the actual cut width. Another way to spread out and aerate the crop for faster drying is with a tedder. Tedders are especially effective with grass crops, but they can cause excessive leaf loss in legumes if done when the leaves are dry. Grasses in particular should be spread in wide swaths, or the forage will settle together and be hard to loosen up to increase the drying rate. Tedders can be a good option when the ground is damp, because the crop can first be mowed into narrow windrows to allow more ground exposure to sunlight, and then―once the soil has dried a bit―the crop can be spread out. Spreading the forage results in faster drying leading to lower neutral detergent fiber (NDF) and higher energy content in the stored forage compared with the slower drying that occurs with narrow swaths.
MECHANICALLY CONDITION THE FORAGE to increase the drying rate of cut forage. Make sure the mowerconditioner is adjusted to cause 90% of the stems to be crimped/cracked (roller conditioners) or abraded (impeller conditioners).
CHEMICAL DESICCANTS are an option to increase drying rate, but only under good drying conditions. They are not effective when conditions are humid, damp and cloudy. They are applied at the time of mowing the crop, so consider the forecasted weather conditions and only apply them if good drying conditions are expected. The most effective desiccants contain potassium carbonate or sodium carbonate. They are more effective on legumes than grasses and most useful for making hay rather than silage or balage. Desiccants work best when applied uniformly to the crop stems when good drying conditions are present.
RAKE THE FORAGE after a period of initial drying. For haylage under good drying conditions, you can usually rake multiple swaths into a windrow about five to seven hours after cutting and right before chopping. For dry hay under good drying conditions, rake multiple swaths into a windrow the next morning after mowing when the forage is 40%–60% percent moisture to avoid excessive leaf loss later when the crop will likely be too dry for raking. Raking should create a swath narrow enough to meet the width of the harvester or baler pickup. Raking also helps create a windrow density to match the harvester or baler capacity. Raking is useful to turn the crop over so the bottom forage can be exposed for faster final drying and to move the swath from wet to dry ground.
STORE AT PROPER DRY MATTER CONTENT. Proper dry matter content for silage ranges from 30%–50% (50%–70% moisture) depending on the structure used, whereas wrapped balage should be dried to 45%–55% percent dry matter (45%–55% moisture). Dry hay should be baled at 80%–87% dry matter (13%–20% moisture), depending on the size of the bale package. The larger and more dense the package, the drier it has to be to avoid spoilage; small rectangular bales can be baled safely at 20% moisture or less, large round bales at 15%–18% moisture, and large rectangular bales at 13%–15% moisture content. If the forage is wetter than these ranges for hay, use hay preservatives (see next column).
PACK AND SEAL UP SILAGE AND HAYLAGE quickly to minimize exposure to oxygen and hasten the fermentation process. For silage, ensure sufficient packing to eliminate much of the oxygen from the pile. For wet wrapped bales, ensure tight bales and wrap them with a minimum of four layers of 1.5-mil thickness of plastic (two turns at 50% overlap) as quickly as possible after baling. More layers are needed when moisture is below the recommended range, in more mature crops, and when baling crops with sharp stems that can puncture the plastic.
HAY PRESERVATIVES can be applied at baling when the hay is a little wetter than ideal for safe preservation of dry hay. The most common and effective preservatives are based on proprionic acid. This acid can be caustic to equipment, but many buffered proprionic preservative products are available on the market that reduce this corrosion problem. The preservatives inhibit mold growth and allow safe baling at moisture contents a little higher than the normal range for dry hay. Preservatives have been most effective on rectangular bales but have questionable effectiveness in large-round bales. Carefully follow the manufacturer’s directions and application rates when using preservatives. Keep in mind that the preservative effect is temporary, so the hay must be dried down to a safe moisture content for long-term storage or used within several months to avoid spoilage.
SILAGE INOCULANTS are often very useful for legume haylage when the wilting phase is short and conditions are cool. For example, lactic acid bacteria inoculants improve fermentation and often provide a good return on investment when putting up alfalfa haylage under those conditions as ofren occurs in the spring, when natural populations of lactic acid bacteria are low on the forage. In contrast, the return on investment for silage inoculants on corn silage is less likely if good management practices are followed.
Some excellent guidelines for putting quality hay and silage, including management guidelines and information on equipment adjustments, can be found at the University of Wisconsin Extension website: fyi.extension.wisc.edu/forage/harvest.