Haylage is a preserved forage created by baling and sealing grass or other crops at a higher moisture content than traditional hay. This process induces anaerobic fermentation, which retains more nutrients and produces a feed that is less dusty than dry hay. This alternative is favored for its higher nutritional value, especially its energy and protein content, making it beneficial for animals with greater dietary demands. Creating quality haylage requires careful, specific steps to ensure successful fermentation and prevent spoilage.
Preparation and Essential Equipment
Producing haylage requires specialized machinery designed to handle the heavier, higher-moisture material efficiently. The initial step is cutting the crop, typically done with a mower-conditioner. This implement not only cuts the grass but also slightly crimps or crushes the stems, a process known as conditioning. Conditioning significantly speeds up the wilting process, allowing the forage to reach the target moisture range more quickly.
The material is then gathered using a specialized, heavy-duty baler built to handle the higher weight and density of semi-wilted forage. These balers must create very tight, dense bales to effectively exclude air, a prerequisite for proper anaerobic fermentation. Finally, a dedicated bale wrapper is necessary to immediately seal the bales in plastic film, creating the air-tight barrier that initiates the fermentation process.
All machinery, particularly the baler and wrapper, must be in excellent working condition before harvest begins. Any malfunction that delays wrapping or compromises bale density can lead to immediate spoilage. A reliable moisture testing device is also necessary, as field decisions rely heavily on accurate moisture readings.
Field Management: Cutting and Achieving Optimal Moisture
The process begins by cutting the forage at the correct stage of plant maturity to maximize nutritional quality. For grasses, this is ideally in the late boot to early head stage, or pre-bloom for legumes, ensuring the highest sugar content necessary to fuel fermentation. Leaving an adequate stubble height is important, as this allows the cut forage to sit slightly elevated, promoting airflow and faster wilting, while also protecting the regrowth of the plant crown.
Once cut, the forage is allowed to wilt in the field, reducing its moisture content from an initial 75% to 85% down to the target range. The optimal moisture content for successful haylage fermentation is between 40% and 60%. For high-quality fermentation, a range of 50% to 60% moisture is preferred, which typically takes only a few hours of drying time in good weather.
Achieving this specific moisture level is the most important step and is confirmed using a specialized moisture meter. Baling the crop above 60% moisture can lead to poor-quality fermentation characterized by butyric acid production, which reduces palatability. Conversely, baling below 40% moisture means there are not enough water-soluble carbohydrates to support fermentation bacteria, resulting in a higher risk of mold growth and poor preservation. Field work must be completed quickly to capture the forage’s quality before weather conditions change.
Baling, Wrapping, and Sealing
Once the forage has wilted to the optimal 40% to 60% moisture level, it must be baled and sealed immediately. The baling step focuses on creating a dense, firm package, which is easier to achieve with round bales. High-density baling is important because it physically excludes much of the oxygen trapped in the forage, which is necessary for anaerobic fermentation. Tight baling also helps the bale maintain its shape for wrapping and stacking.
The bales must be sealed as quickly as possible after baling, ideally within two to four hours, to prevent aerobic spoilage. Exposure to air allows undesirable microbes to consume plant sugars, wasting the energy reserves needed for fermentation. The wrapping process requires specialized silage film, which must be applied with sufficient tension to expel remaining air pockets and create a completely air-tight seal.
For effective preservation, it is recommended to apply a minimum of six to eight layers of plastic film to the bale. This thickness provides a robust physical barrier against oxygen infiltration and puncture damage. High-quality plastic is also treated to resist ultraviolet (UV) light degradation, ensuring the seal remains intact throughout storage. Immediate and thorough sealing creates the anaerobic environment, allowing Lactobacillus bacteria to convert forage sugars into lactic acid, which lowers the pH for long-term storage.
Monitoring and Safe Storage
After wrapping, the haylage bales must be handled carefully and moved to a safe storage location. During the initial fermentation period, which typically lasts four to eight weeks, the internal temperature of the bale may rise but should stabilize as the pH drops. Proper stacking involves placing bales on a level surface free of sharp objects, such as stones or stubble, that could puncture the plastic wrap.
Maintaining the integrity of the plastic seal is a continuous management task throughout storage. Any tear or puncture in the film allows oxygen to enter, which immediately stops the anaerobic fermentation process and creates a site for mold and yeast growth. Bales should be checked frequently for damage caused by birds, rodents, or handling, and any holes must be repaired immediately using specialized sealing tape.
A breach in the seal, especially if unaddressed, can lead to the proliferation of harmful bacteria, including Clostridium botulinum, which produces a potent toxin responsible for botulism. Maintaining the oxygen-free environment is necessary for animal safety. The post-production phase focuses entirely on preserving the anaerobic state created by the initial sealing process until the haylage is ready to be fed.