Drought-damaged corn can make good feed when chopped for silage, but growers tend to harvest it when it’s too wet, resulting in poor fermentation, warns Keith Johnson, Purdue Extension forage specialist.
“Ideally, the crop should contain 60-70% moisture at harvest,” says Johnson. “For upright silos, to avoid seepage, growers should harvest at 60-65%. For bunker silos, harvesting at 65-70% moisture will result in better packing and storage qualities.”
Plants with brown leaves and small ears with little or no grain may still be too wet because most of the moisture is in the stalks, he says.
“A quick way to determine if the plant contains too much moisture is to hand-squeeze a representative sample collected from the forage chopper. If water drips from the squeezed sample, the corn is too wet for ideal fermentation.”
Most studies indicate that the feed value of properly fermented, drought-stressed corn silage is 80-100% that of normal silage. Purdue trials revealed little or no difference in feedlot gain or milk production when beef and dairy cattle were fed normal or stressed corn silage. But, as a rule, Johnson says drought-stressed corn has slightly more fiber, less energy and 1-2% more protein.
Although potential for nitrate toxicity after fermentation is reduced, livestock producers who will use the corn for silage should have that silage analyzed for nitrates.
Producers with short pasture and stored feed supplies might also consider harvesting drought-damaged corn as greenchop. Two potential problems are nitrate toxicity and laminitis. Johnson lists these steps to help avoid them:
● Raise the cutter bar to 12” the first few days of chopping.
● Gradually introduce animals to greenchop.
● Use other feeds that are low in nitrate as part of the ration.
● Feed greenchop in small quantities throughout the day rather than large quantities once per day.
● Don’t allow greenchop forage to sit on a wagon overnight.
● Feed 2-3 lbs of grain with high-nitrate feeds.
● Take extra precautions during the first two or three days following rain because nitrate levels tend to increase during that period.
“As plants mature, nitrate levels decline, so animals become acclimated and the chances for toxicity decrease over time,” says Johnson.
Corn growers looking to sell drought-damaged corn for silage, and livestock producers looking to buy it, need to understand how to properly price the crop. For help figuring its value, read Determining a Value for Corn Silage and Determining the Costs of Corn Silage Standing in the Field. More information is available in Johnson’s Web-based publication, Drought-Damaged Corn as Livestock Feed.
Before making any decisions about drought-damaged corn, check with crop insurance agents so the crop can be appraised for damage prior to harvest, he says. Also, pay close attention to herbicide and insecticide labels and be in touch with chemical suppliers to make sure the crop is harvested and fed safely.
The video, Harvesting Drought-Stressed Corn for Forage, gives advice by University of Georgia Extension forage specialist Dennis Hancock.