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 narrow grasses should be cut at the boot stage, 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 like orchardgrass mature more quickly than legumes. Missing this window by even 10 days can result in significant losses in both total digestible nutrients (TDN) 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 48–50% TDN and 12% protein or less.
To make the most of limited drying windows, mowing should begin mid-morning 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 around 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.
Source : osu.edu