Too much rain can create forage challenges

Spring planting was nearly ideal across much of the Midwest with great soil conditions and few rain interruptions. Since then, many areas have received above-average rain-fall. Adequate precipitation is valuable, but excessive moisture can create challenges for growing, harvesting, storing and feeding alfalfa and corn silage.

Alfalfa hay and silage

Many folks have heard the phrase “Alfalfa does not like having wet feet.” Excessive moisture saturates the soil, which can trigger an imbalance in oxygen and moisture in the root system and suffocate the plant. This creates a perfect environment for root rot and plant diseases such as leaf spot. Saturated soils cannot handle the weight of equipment, which can lead to damage of plant crowns. This is especially concerning in delicate, new seeding stands.

Harvesting alfalfa has been a challenge with this season’s rain frequency. Unrelenting rain has altered the cutting schedule in many fields, often resulting in reduced digestibility and lower protein and energy. Finding a window to harvest alfalfa for dry baled hay has been nearly impossible in many regions. For some, plans to make dry hay have pivoted to haylage or balage to accommodate harvesting at higher moisture levels and less drying time.

Alfalfa’s higher protein and mineral content creates a buffering effect that works against a fast pH drop in the silage. When rain falls on cut alfalfa, it washes away sugars and beneficial bacteria that fuel fermentation, further challenging an adequate and quick pH drop. In addition, rained-on alfalfa can experience soil splashing, resulting in higher-than-ideal ash content. All this creates perfect conditions for clostridial fermentation. Sound harvest and storage practices are critical for rained-on hay to drop the silage pH as quickly as possible upon ensiling and decrease clostridial impact.

Clostridia are slow-growing microorganisms. If silage has a high risk for clostridial fermentation, segregate it so it can be fed as soon as possible before the silage turns butyric. Elevated levels of butyric acid in silage often lead to reduced dry matter intake and an in-crease in cow health issues, including silage-induced ketosis in fresh cows.

Corn silage

Sufficient moisture combined with plenty of heat and humidity has resulted in rapid growth of corn plants and earlier tasseling across many fields. Corn, too, can be challenged with excessive rain. Too much moisture results in leaching of key nutrients, including nitrogen and sulfur, from the plant. This causes issues such as yellowing of the corn and dis-ease concerns such as root rot. A lack of nitrogen and sulfur also causes stunted growth of the plant, resulting in lower fiber and higher starch content.

Wet conditions may make it hard for the corn plant to dry down to 32%-35% dry matter, which is ideal for harvest, storage and fermentation. Field topography during wet years results in great variability in tonnage and quality. The wet conditions also create field challenges for equipment and contingency plans for dealing with mud.

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. Employing top-notch harvest and storage practices remains paramount to minimizing these risks.

Despite a problematic wet season, careful management strategies can fuel success in alfalfa and corn silage production. Understand the effects of rain, strike a balance between production and quality and implement proactive soil and fertility management. Work with your agronomy and nutrition advisers to effectively manage weather difficulties and fertility concerns to ensure high yields and quality forage.

Barry Visser is a nutritionist for Vita Plus.