Be aware that a frost can cause prussic acid to build up in sudangrass and sorghum forages, poisoning livestock if fed too soon after the frost event, according to Extension Forage Specialist Yoana Newman.

In sandy soils of Wisconsin, livestock producers are becoming more interested in sorghum grasses. These are tropical summer grasses that are adapted to drought conditions due to a waxy cover on their leaves and stems that retains water.

"We call them the camel of grasses, because they're very well adapted to limited rain and very high temperatures," Newman says.

Something that producers need to be aware of this time of year is that a frost, even a light frost, with sudangrass, sorghum, and sorghum sudangrass hybrids causes prussic acid to build up in the forage. Prussic acid will poison livestock, and it's lethal.

"But it's a temporary condition, so if you know that your stand has frozen, what you need to do is have a precautionary measure there not to graze the stand or offer it to animals in probably about a week's time or that prussic acid that has formed would be gone, totally gone," Newman says.