Growing conditions have a significant impact on the nutritional value of corn silage, and though growers can't change Mother Nature, they can be prepared and make adjustments during harvest that can have a positive outcome for their crop, according to experts from Pioneer Hi-Bred, a DuPont business.
Growers can manage their corn silage through hybrid selection, digestibility testing, chopping height and inoculant use.
The environmental impacts from heat, moisture and light can have different effects on the nutritional value of corn silage. And there can be different impacts during each stage of growth.
"Water is a major factor in the value of corn silage," says Jim Smith, Pioneer livestock information manager. "If you have excess water pre-pollination, it will impact the digestibility of the fiber in the plant negatively. However, the extra moisture will provide growth and tonnage."
Toward the later part of the corn plant's growth cycle, water will add to the grain portion of the plant, adding energy deposition to the plant. Of the total energy available in corn silage, about 65 percent of that energy originates from the grain which comprises approximately 50 percent of the silage on a weight basis. About 25 percent of the total energy will come from the fiber portion of the plant, and the remaining 10 percent comes from the cell contents of the plant.
"Energy is the vital nutrient that corn silage supplies to livestock," Smith says. "If development of the kernels during pollination is impacted by environmental conditions, the grain - and energy - will be impacted, as well."
Heat and light also can affect corn silage. Heat is important to bring the corn plant to a harvestable maturity. Excess heat combined with excess water during the vegetative stage of growth can be compounding negative effects on fiber digestibility. Light is always a positive since plants need sunlight for photosynthesis.
To a certain extent, growers can implement management strategies to reduce the effects of negative growing conditions.
"Choosing the right hybrid, along with timely planting and good basic agronomic practices, makes a difference," Smith notes.
Hybrid selection is a grower's first line of defense against any environmental effects on corn silage. According to experts at Pioneer, the correct maturity for a particular growing area for corn silages is five to 10 days longer in relative maturity than planting corn for grain.
Smith suggests growers can get a good indication of what impact the growing season has had on the crop before harvest. Check the digestibility by taking a good sample of the crop and send it to a lab for testing. "If the sample is relatively low in digestibility, try chopping higher to reduce the amount of stalk, which is the most indigestible part of the plant," Smith says. "Also, inoculate with crop-specific inoculants to maximize dry matter recovery and animal performance. Within the crop-specific offerings of Pioneer corn silage inoculants, every bacterial inoculant provides an excellent initial fermentation. Depending on the specific needs of an individual operation, other products in the corn silage inoculant line have additional benefits, such as increased aerobic stability at feedout and improved fiber digestibility."