Toxic Plants in Pastures
Toxic plants are a legitimate concern for livestock producers, especially when drought, flooding, or heavy grazing pressure alter plant communities.
But while the risk is real, it can often be managed with informed decisions
and a few practical strategies.
The first step is identification. Some of Nebraska's most problematic spe -
cies - like poison and water hemlock, Lambert crazyweed, chokecherry, and prairie larkspur - can be toxic even in small amounts. Others, like wild
carrot, pigweed, hoary alyssum, and white snakeroot are harmful only in large
quantities or under specific conditions. Correct ID is a critical first step for toxic plant management. For instance,
milkweed species vary in toxicity — some highly dangerous in small doses, others requiring much greater intake. Nebraska Extension's EC3037: Plants Toxic to Livestock is a wonderful resource with photos and descriptions to help, or reach out to your local Extension office with samples or clear photos.
It's important to remember that most pastures contain some toxic plants - but livestock losses are rare. Animals with sufficient forage generally avoid harmful species. Problems arise when pastures are overgrazed, droughtstressed, or when animals enter a new area hungry. Hay can also pose a risk; toxic plants may be harder to recognize when dried but retain their toxicity.
Common toxic plants in our region include poison and water hemlock (among the most poisonous plants in North America), hoary alyssum (espe cially dangerous to horses in hay), white snakeroot (can pass through milk causing risk for calves and milk drinkers), milkweeds, Lambert crazyweed, and prairie larkspur. Managing the risk means reducing the chance of ingestion. Maintain ad -
equate forage to limit grazing pressure. This is especially important at the beginning of the grazing season and during drought events.
Move animals into new pastures with full stomachs to prevent exploratory grazing. Monitor plant communities regularly. Herbicide control in spring or fall can reduce problem plants but use caution near sensitive areas. Spot spraying or mechanical removal may be better options there.
In some cases, herbicide treatments may remove the natural bitterness of toxic plants, making them more palatable and increasing the risk of ingestion. For hay, especially from unfamiliar sources, inspect bales closely and test if needed. Dried toxic plants are less obvious but still potent.
To help producers manage these risks, Nebraska Extension is offering a webinar series on Toxic Plants and Livestock Health. The sessions will cover plant ID, toxicity impacts, and prevention strategies. Registered participants will receive a printed copy of EC3037 for on-farm reference and a recording of all sessions to view later. Visit go.unl.edu/toxicplants to register or learn more.
