Prussic acid poisoning is a very critical issue during hay season.
Prussic acid is a chemical in plants, such as: Johnsongrass and wild cherry trees – that in the right state – can kill cattle.
There are many factors that influence the prussic acid content in plants: height, soil fertility, frost and drought.
According to Benton County, Ark., Extension Agent Johnny Gunsaulis, hay season and frost are the most important times for livestock producers to watch their herd.
“During regrowth is when livestock producers need to watch close,” Gunsaulis said. “Frost is also an important time to watch.”
Johnsongrass is a danger after the pasture has been cut for hay – it has rained – and new grass has began to grow.
Gunsaulis recommended that Johnsongrass be knee high before turning in cattle and the herd not be too hungry.
In the right state Johnsongrass is very beneficial to graze or bale.
Arkansas Cattle and Chicken Producer George Anderson said his cattle milk better on Johnsongrass than Bermuda.
“It’s been a mild, wet year – a great year for Johnsongrass,” Anderson said.
Prussic acid may be higher in plants that are deficient in phosphorus.
A seasoned producer, Anderson knows the benefits of chicken litter as a fertilizer.
“Prior to chicken litter, our Johnsongrass was more poisonous,” Anderson said.
Frost, Gunsaulis said, is another crucial time for producers to keep an eye on their herds.
“Plant cells are damaged in Johnsongrass after it has frosted causing more prussic acid to be in the grass while it is drying. “ Gunsaulis said.
Wild cherry trees also have prussic acid.
Gunsaulis said that healthy wild cherry trees are not a hazard.
“Green is good,” Gunsaulis said. “Wilting leaves is when it’s dangerous.”
In the same way the prussic acid content is higher in drying Johnsongrass, wilting leaves have a higher acid content until dried out.
Gunsaulis and Anderson both stressed the importance of being aware of the herd and it’s surroundings.
“We are aware of what pasture we are grazing – especially when it’s dry,” Anderson said.
Gunsaulis said, “Knee high is fine.”
