Light Frosts May Add Prussic Acid Problems To Nitrate Toxicity Concerns
Prussic acid when ingested by cattle, is quickly absorbed into the blood stream, and blocks the animal’s cells from utilizing oxygen. Thus the animal dies from asphyxiation at the cellular level. Animals affected by prussic acid poisoning exhibit a characteristic bright red blood just prior to and during death. Lush young regrowth of sorghum plants are prone to accumulate prussic acid especially when the plants are stressed such as drought or freeze damage. Several nights have recently reached the freezing mark. Light frosts, that stress the plant but do not kill it, are often associated with prussic acid poisonings. Producers should avoid grazing fields with sorghum type plants following a light frost. The risk of prussic acid poisoning will be reduced, if grazing is delayed until at least one week after a “killing freeze”.