Prussic acid poisoning is a risk for livestock grazing which of the following forage crops?

Prussic acid poisoning is primarily associated with certain types of sorghums, including sudangrass and hybrid sorghum varieties. These plants can produce high levels of hydrogen cyanide, particularly under certain stress conditions such as drought, frost, or rapid growth following a period of water deficiency. This toxin can accumulate in the plant, especially in the younger, more rapidly growing tissues.

Sorghum species have a specific metabolic pathway that can convert cyanogenic compounds into prussic acid, making them a significant risk for livestock that graze on them. Awareness of the conditions that promote high prussic acid levels in these forages is crucial for effective management and safety when grazing. In contrast, the other forages listed, such as fescue, winter wheat, and native range grasses, do not typically pose the same level of risk for prussic acid poisoning.