Many areas of the country have received above-average rainfall this year. This creates challenges harvesting, storing, and feeding forages. Let’s explore strategies to get the most from wet alfalfa and corn silage.
Alfalfa does not like to have wet feet. Heavy moisture conditions saturate the soil, suffocate the plant, and trigger an imbalance in oxygen and moisture in the root system. This creates a perfect environment for root rot and plant diseases such as leaf spot to flare up. Saturated soils cannot handle the weight of the equipment, which can lead to damage of plant crowns.
When rain falls on cut alfalfa, it washes away sugars that fuel fermentation and thus prevents an adequate and quick pH drop. Recall that alfalfa’s higher protein and mineral content creates a buffering effect that also works against a fast pH drop. In addition, rained-on alfalfa will probably also have higher-than-ideal ash content. All this creates the perfect breeding ground for a clostridial fermentation. Dropping the silage pH as quickly as possible upon ensiling has been shown to decrease clostridial impact. Using a high-quality upfront inoculant such as Crop-N-Rich® MTD/1® is crucial to lower the pH as quickly as possible.
Clostridia are slow-growing microorganisms. If a silage has a high risk for clostridial fermentation, segregate it so that it can be fed as soon as possible before the silage turns butyric. Elevated levels of butyric acid in a silage often lead to reduced dry matter intake, and silage-induced ketosis has been reported.
Corn silage
Corn does not like wet feet, either. Too much moisture results in leaching of key nutrients — nitrogen and sulfur — from the plant. This causes issues such as yellowing of the corn and disease concerns such as root rot. Lack of nitrogen and sulfur also causes stunted growth of the corn plant, resulting in lower fiber and a higher starch content.
Wet conditions make it hard for the corn plant to dry down to 32% to 37% dry matter, which is ideal for storage and fermentation. The wet conditions also create field challenges for equipment. Field topography during wet years results in great variability in tonnage and quality.
When feeding corn silage that has been impacted by wet growing and harvesting conditions, lower fiber and starch digestibility is likely along with protein degradation from the presence of mold and fungus. Mycotoxins may also be a concern. Work with your nutritionist to determine the best strategy to meet the nutritional needs of your herd when corn silage doesn’t meet tonnage and quality targets.
Having a plan in place will help you navigate the challenges that come along with excess moisture during growing and harvesting. Consider the impact moisture can have on the crop itself as well as the fermentation process. Building a plan now will help mitigate challenges in the future.
