Dealing with Poor Corn Silage
by Dr. Clay Zimmerman
The first cause of poor corn silage is the typical "new corn silage slump" that we experience most years. New corn silage slump occurs when you begin feeding new crop corn silage that has been recently harvested but has completed fermentation, yet milk production drops. The drops seem to be higher in herds feeding high levels of corn silage and high producing cows seem to be affected the most. The trademark of this problem is undigested kernels showing up in the manure and it may not be related to a drop in feed intake. These problems seem to clear up as time passes and are usually not noticeable by mid-winter. Sound familiar? A second cause of poor corn silage can be an unusually cool and wet growing season, combined with an early frost. These growing conditions will probably result in new corn silage that has poor fiber digestibility.
How do we deal with these two problems? If you are having problems with new corn silage, decide which problem you are dealing with and act accordingly, because the nutritional strategies are very different.
Dealing with "New Corn Silage Slump"
"New corn silage slump" occurs when kernels become hard and resistant to breakage and digestion. At harvest time, kernels are normally much drier than stover and if silage is harvested too dry, the kernels become even harder and drier. Why does the slump go away? Because after kernels "stew" in the silage juices long enough, they absorb moisture and become softer and break more easily. Why doesn't the slump occur every year? The slump is avoided or reduced in cool years or years in which corn planting is delayed. Some years the kernels are wetter than usual at harvest and this will avert the problem.
What can be done to eliminate the slump?
1. One suggestion is to have enough excess corn silage inventory at the end of the harvest season so that you don't have to feed the new crop corn silage for 2 to 3 months. This gives the new silage time to stew. If a farm uses bags of silage it is very easy to have enough extra in a bag or 2 to feed for the first few months. The other possibility would be to have a bunker silo that you can feed out of both ends, thus being able to feed old crop corn silage for a few months.
2. Process corn silage with a roller to crush the kernels. This can be accomplished with a kernel processor mounted on the silage harvester or by running chopped silage through a roller mill. The benefits of corn silage processing are mainly to crush the kernels, making them more digestible but proper corn silage processing may increase the digestibility of the fibrous fractions as well, including the stalk and cob. Processed corn silage can also be cut longer (3/4") than unprocessed corn silage (3/8") because the processed silage packs better than unprocessed silage, thus allowing for increased effective fiber from processed silage.
3. Select a corn hybrid that is less prone to cause the slump. Silage hybrids should have kernels that stay moist and soft while the stover dries down. However, for grain varieties the opposite is true
© Blue Seal Feeds – October, 2000