Hay is a dried forage crop, typically composed of grasses or legumes, providing necessary nutrition for livestock. This preserved vegetation allows farmers to maintain animal health and diet when fresh pasture is unavailable, particularly during winter. The haymaking process focuses on rapid moisture removal and careful packaging to preserve maximum nutrients.
Harvesting and Curing the Crop
The haymaking process begins with specialized machinery, such as a mower-conditioner, which cuts the standing crop and immediately crimps or conditions the stems. This conditioning step opens the waxy layer on the plant stems, significantly accelerating the rate at which moisture can escape. The cut crop is laid out across the field in wide rows known as swaths to maximize sun and air exposure.
The primary goal is curing, reducing the plant’s moisture content from its fresh state to below 20% to prevent spoilage. If drying is slow or the weather is humid, a hay tedder is used to fluff and spread the material, ensuring uniform drying. The tedder lifts the hay off the ground and aerates it, substantially reducing the dry-down time. Faster curing retains more nutrients, as the plant stops consuming its stored carbohydrates.
Gathering the Material for Baling
Once the hay has cured to the appropriate moisture level, it must be gathered into uniform rows for the baling machine. This critical step is performed by a hay rake, which sweeps the widely spread swaths into dense, continuous lines called windrows. The consistency of these windrows is important because it dictates the efficiency and density of the final bales.
Timing the raking process is important; the hay must be dry enough to store but not so dry that its leaves shatter. Leaves of legume crops hold the majority of the protein and nutrients, so excessive leaf loss reduces the hay’s feed quality. Producers often rake in the early morning or late evening when dew slightly moistens the material, making the leaves more pliable and less likely to break off.
Compression and Safe Storage
The final stage involves the baler, which travels down the windrows, compressing the loose hay into stable, transportable packages. Modern balers produce various forms, including small square bales, large square bales, and cylindrical round bales, each having different density and handling characteristics. The density of the package directly influences the maximum safe moisture level; small, less dense bales tolerate a slightly higher moisture content, sometimes up to 18–20%.
Denser bales retain heat more effectively and require the hay to be drier for safe long-term storage. Hay baled with moisture content above 20% is at a high risk for spoilage and spontaneous combustion. This fire risk occurs because high moisture enables aerobic bacteria and fungi to break down the plant material, generating heat through microbial activity.
If the internal temperature of the bale continues to rise, the heat can initiate a self-sustaining exothermic chemical reaction leading to ignition. Hay should be stored in covered areas, such as barns, and elevated off the ground to prevent moisture wicking. Monitoring moisture content and proper storage ensure the hay remains a safe and nutritious feed source for livestock.