Livestock forages in the sorghum family (johnsongrass, forage sorghums, sorghum-sudangrass) can be poisonous to livestock if consumed right after a frost, extension officials warn.
“These forages produce prussic acid (cyanide) right after a frost or freeze which is very deadly,” said David Qualls, county director, Lincoln County Extension. “The prussic acid will break down over the course of 7 to 10 days, so if the grass is cut for hay, by the time the haymaking process is complete, the danger from prussic acid poisoning is gone.
“The poison goes off as a gas during the drying process,” said Qualls. “Producers can make hay or haylage from frosted johnsongrass or sorghum/sudangrass, but should not graze it. To save pastures containing these forages for grazing, wait until the grass has been completely killed by frost, then wait 10 days prior to grazing.”
For more information, call the Lincoln County Extension Service at 433-1582.