Graze with caution
With drought conditions worsening and the potential for frost approaching, a couple of pasture plants are of concern.
1) Perilla mint: the broadleaf weed pictured. This weed is toxic to cattle and horses most often. As good forages are depleted, livestock are more likely to consume perilla. This weed favors shaded areas and high-traffic areas around corrals and such. It is in the mint family, has a square stem and does have a minty smell when crushed. It has a purple bloom and its toxicity is greater the more mature it gets so right now, it is likely to cause animal death if consumed in great enough quantities as has been reported in surrounding counties.
2) Johnsongrass: Drought stress and frost both have the potential to raise toxic Prussic acid levels in johnsongrass which can cause death in ruminants. Johnsongrass shorter than 18” has the highest potential for prussic acid accumulation. If you begin to notice wilting from drought, discontinue grazing. Should we get a rain, those toxic levels will spike, so keep animals off for up to four days after a rain. If we do get a frost, don’t allow livestock to graze the field until it’s dried to the color of a brown paper sack, usually around 7 days.
