Weed wiper... Johnson grass. Anyone using one?

[Jrasband]

It is easy to avoid prussic acid poisoning with rotational grazing. Unfortunately, most cattle farms are not rotational grazers.

 

[Dadnatron]

It is easy to avoid prussic acid poisoning with rotational grazing. Unfortunately, most cattle farms are not rotational grazers.

How long, after stress ie drought and/or frost, would you wait before putting them back into a pasture that has JG in it?

This is the information I don't know. How long must I avoid that pasture to be safe. I've heard a week or so, but I don't know.

 

[Jrasband]

Prussic Acid Johnsongrass Duration
Prussic acid can be a concern with Johnson grass for a period of time after the plant is stressed, such as during drought or frost. The risk is highest in young plants and during periods of stress. For example, after a frost, prussic acid levels can be particularly high and may persist for a few days.
It is recommended to wait at least 14 days after a frost before allowing livestock to graze on pastures with Johnson grass to ensure that prussic acid levels have subsided.
Additionally, if Johnson grass is mowed and baled, the prussic acid will dissipate over time, and it is advised to wait at least 90 days for the hay to cure before feeding it to cows.
In some cases, prussic acid can decline within 2 to 3 days after the plant is dead, but it is still important to exercise caution and follow recommended guidelines to ensure the safety of livestock.

AI-generated answer. Please verify critical facts.

 

[Blue Mule]

Sorry to bring this topic back up, but this summer proved to be relentless for my lawn directly around my house. The fields are fine, but I don't want Johnson Grass around my house. It's unsightly and it chokes out fescue and other desirable lawn grasses. I have tried to manually dig out as much of it as I can, but it's quickly going out of control. I've got a few 10' x 10' patches of it now that are spreading. It would take a month of Sundays to manually dig that all out with a garden spade.

So back to the topic of herbicides.. are there any that I can actually purchase myself that are effective at controlling Johnson Grass but will not harm fescue? I know that's a tall order, but if one exists please list it and I'll buy some.