by Ted Wiseman
Harvesting first-cutting forages during a wet spring is always a challenge, but timing remains critical for maintaining forage quality.
Studies have shown that the ideal harvest window is at boot stage for narrow grasses, while legumes are best harvested at late bud to early bloom. In mixed stands, the timing should be based on the grass component, as grasses such as orchardgrass mature more quickly than legumes.
Missing this window by even 10 days can result in significant losses in both total digestible nutrients and crude protein. For example, an alfalfa-grass mix harvested at the right stage can contain 65% TDN and 18% protein, while the same stand cut at half bloom or later may drop to just 48% to 50% TDN and 12% protein or less.
To make the most of limited drying windows, mowing should begin midmorning after the dew has evaporated. Although afternoon mowing can increase sugar content, maximizing drying time is usually more important in wet conditions. Cutting height should be maintained at 3 to 4 inches to encourage regrowth, extend stand life and improve airflow for drying.
Mower conditioners should be adjusted to crimp stems every 3 to 4 inches, and the swath should be as wide as possible — ideally covering at least 70% of the mower’s cutting width. Tedding or raking should be done when the forage is about 40% moisture to minimize leaf loss.
Care should be taken to avoid soil contamination during raking, as soil is the primary source of Clostridium bacteria, which can cause fermentation issues in baleage and haylage.
Rakes should be set with the minimum down pressure needed to form windrows. If there is concern about contamination, a forage test for ash content can help; values above 11% suggest excessive soil and increased risk of poor fermentation.
Moisture content at baling is another key factor in preserving forage quality. For dry hay, the ideal moisture range is 15% to 20%, depending on bale type. Minimum moisture levels should be 20% for small square bales, 18% for large round bales and 17% for large square bales. Baleage should be baled at 45% to 65% moisture and wrapped with at least six layers of one-mil plastic.
Proper moisture levels are essential to prevent clostridial fermentation. While estimating moisture content in the field is possible, no method is both fast and highly accurate. For haylage, forage should be chopped at 60% to 70% moisture and packed into a bunker, silo or bag.
Proper storage
Storage practices also play a major role in preserving forage quality. For wrapped or bagged forages, any holes or tears in the plastic should be repaired immediately, especially during the first month when most fermentation activity occurs.
Dry hay stored indoors should be monitored closely if baled above 20% moisture. Outdoor storage typically results in the highest losses due to moisture at baling, precipitation during storage, poor drainage and inadequate spacing between bales.
The most easily measured storage loss is total dry matter loss, which typically ranges from 6% to 15%, with most losses closer to 15%. Additionally, the outer layers of bales often lose digestibility due to weathering. Combined, these losses can reduce the feeding value of a round bale by up to 25%.
To minimize these losses, bales should be stored on well-drained ground, spaced at least 3 feet apart, and kept away from tree cover. Using tarps or storing bales indoors can significantly reduce losses and help maintain forage quality.
During less-than-ideal and limited weather conditions for harvesting forages, it’s important to keep safety a top priority. While it can be tempting to push through and get the job done, the risks often outweigh the rewards. Baling hay that’s too wet can lead to spontaneous combustion and hay fires, which can destroy barns and equipment.
In the long run, losing a few bales is far less costly than replacing a barn or risking injury. Take the time to monitor conditions, work safely, and protect both your harvest and your operation.
Wiseman is the Ohio State University Extension educator in Perry County and a member of the OSU Extension Beef Team. The Beef Team publishes the weekly Ohio BEEF Cattle letter, which can be received via email or found at their website beef.osu.edu.