COLUMBUS – Farmers should harvest their drought-stressed corn for silage at the correct dry matter content to maximize yields and improve the feeding value.
Bill Weiss, an Ohio State University animal scientist, said that although many areas in Ohio are experiencing drought conditions that would drive growers to harvest early, drought-stressed corn should be harvested no earlier than normal corn silage.
Don’t rush. “The condition of drought-stressed corn is the main reason why farmers harvest their crop early. It looks drier than it really is,” Weiss said. “But farmers should wait to get the best dry matter content, especially since drought conditions may produce low corn yields this season.”
Farmers can send a sample of their corn to a laboratory to measure dry matter content. For good fermentation in the silo and good feeding value, dry matter content of 30 percent to 40 percent is an acceptable range, although 32 percent to 38 percent is ideal.
If a farmer is storing corn in a bunker silo, dry matter content should be in the 30 percent to 35 percent range, Weiss said. If he has a tower silo, he’d want a higher dry matter percentage.
Feed value varies. Although harvest recommendations are similar for normal and drought-stressed corn, the nutritional value of the resulting feed may be different.
Drought-stressed corn should be tested for nitrogen-nitrate concentrations before being fed to livestock.
OSU horticulturist Peter Thomison said drought-stressed corn tends to accumulate toxic levels of nitrates in the stalks and stems that may make the crop unsuitable for feed.
“If growers want to salvage part of their drought-damaged crop for silage, it’s best to delay harvesting to maximize grain filling,” Thomison said. “If nitrate levels are high or questionable, they will decrease as the plant gets older and nitrates are converted to proteins in the ears.”
Nitrogen-nitrate concentrations of less than 2,000 parts per million in dairy cattle are preferable, Weiss said. Any number above 4,000 parts per million is considered unsuitable for feed, and the feed should be diluted if figures fall between 2,000 and 4,000 parts per million.
