Temperatures in the Northern Plains have either already dropped below freezing or will be soon. While there is not an issue with grazing or feeding most forage frosted crops, some can be toxic when fed to livestock. Sorghum and sudangrass grazed or harvested immediately following a killing frost can contain high concentrations of prussic acid. University of Minnesota Extension recommends testing the forage and letting the forage dry down for one to two weeks after a killing frost.
