Ranchers concerned eating newly-sprouted Johnson Grass may harm livestock

LUFKIN, Texas (KTRE) - The rain is a welcome sight as most East Texas counties remain under burn bans, but this week’s rainfall can lead to what’s known as Johnson grass, a weed that can be highly toxic to animals.

Vanessa Corriher-Olson is a forage specialist at the Texas A&M Agrilife Extension.

Olson said, “A lot of folks get concerned about grazing or feeding Johnson grass because of a potential toxicity risk that could potentially if consumed at high rates, high levels of hydrogen cyanide could be deadly to livestock, especially cattle.”

She said Johnson grass is very adaptive to East Texas.

She said it grows on roadsides, in ditches, and can be found in some pastures and hay bales.

“Based on some preliminary research, some of our findings have shown that plant maturity has a big impact on potential hydrogen cyanide or hydrogen cyanide potential,” said Olson.

She said the younger plant has a greater risk than the mature plant.

“Some of our recommendations are to monitor the areas that your livestock are grazing. If there is Johnson grass in that area. If they’ve already been grazing the Johnson grass that’s very mature, that’s not likely to be much concern,” she said.

Olson said if you have young growth, new growth or regrowth of Johnson grass, you will need to move your livestock to another location where there’s not any Johnson grass to allow young Johnson grass to mature before animals graze on it.

“Anytime we’re buying hay, especially from an unknown source, or we have concerns of potentially toxic components ,not just Johnson grass, but potentially some other toxic components, I recommend that they have their hay analyzed,” said Olson.

She said to send a forage sample to an appropriate lab to look at those potential toxic pieces including hydrogen cyanide potential.

Olson said as we get more rain, any young or immature Johnson grass will mature and continue to grow.

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