Warning: Do Not Graze Frost Bitten Johnson Grass
I hope all is well on your farm and you are enjoying these cooler temperatures! With the threat of frost
this week, cattle producers should be aware of the risk for prussic acid poisoning when cattle are grazing
frost bitten Johnson grass.
When Johnson grass is frost bitten, prussic acid, a form of cyanide,develops within the plant. Once
plants containing prussic acid have been eaten, the toxin quickly enters the blood stream and spreads
through the body of the animal. Prussic acid interferes the body's ability to process oxygen. Therefore,
the animal essential suffocates.
While prussic acid poisoning can effect any animal that eats it, ruminant animals are more susceptible to
prussic acid poisoning than non-ruminant animals because their microorganisms have enzymes which
will release prussic acid in the animal's digestive tract.
Signs of poisoning can occur within minutes to hours of the animal consuming the toxic
forage. Symptoms include tremors, and rapid breathing. There may also be drooling, runny eyes, and
staggering prior to collapse.
Producers can make hay or haylage from frosted johnsongrass since prussic acid dissipates when the
plant is cut and lays for a few days, but do not graze it. To save it for grazing, wait until the grass has
been completely killed by frost, then wait 18-21 days prior to grazing.
Gilbert Barrett, President/CEO
706-865-2831
www.wcfecoop.com
gibbarrett@gmail.com