Poisonous Plants to Goats: Alkaloids
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Poisonous plants to goats can cause anything from an upset stomach to death. Find out if your fields are harboring dangerous plants.
As the weather warms, people start asking: Can goat eat tomatoes? Can my goats eat these flowers? Is this shrub okay for my goats? What plants are poisonous to goats? In this second part of the poisonous plants series, we’ll explore Alkaloids. Finding information on all the plants that are poisonous to goats can be challenging. The FDA poison plants website, which was the previous source for plants that are poisonous to goats, no longer exists. Consequently, I’ve had to cobble together information on poisonous plants from various sources.
Alkaloids impact the liver and can cause lethargy, weakness, and teeth grinding.
Digestive issues include:
- Vomiting (goats rarely vomit, so this would be cause for immediate action)
- Diarrhea
- Drooling
- Bloat
Nervous system effects include:
- Loss of coordination
- Seizures
- Coma
- Death
In some cases, the alkaloids found in plants can accumulate in the body and cause symptoms in the adult goat but may cause birth defects in the kids of pregnant goats.
Plants
Senecio
This genus of plants in the daisy family includes ragwort, groundsel, and butterweed. About 25 of the approximately 70 species in North America are known to be poisonous to animals. There’s no clear guidance on whether the remainder of plants in the genus are poisonous or not.
The most well-known plant in the genus is tansy ragwort (S. jacobaea). This yellow-flowered plant is commonly found in pastures. According to A Guide to Plant Poisoning of Animals in North America, identifying individual members of Senecio can be challenging; all those in the genus have “a single layer of bracts (modified leaves) touching, but not overlapping the flower.”
Although this plant, which contains pyrrolizidine alkaloids (PAs), is well-known to horse and cattle owners to be poisonous to their animals, goats have been considered mostly resistant to it. I’ve had small amounts pop up in my pasture over the years, but my goats have shown little or no interest in eating it.
According to an article in the Canadian Veterinary Journal (2017), two of three Pygmy goats died after browsing in a pasture that contained a large amount of tansy. The authors noted that toxicity is usually due to chronic exposure to a large amount of the plant.
All parts of the plant are poisonous. In addition to immediate signs and symptoms, it can lead to birth defects in fetuses and can even be toxic to humans because it’s excreted in milk.
Nightshade Family
Many plants in the nightshade family are foods we usually eat, such as tomatoes, potatoes, and eggplants. The plants of greatest concern for goats are jimsonweed (Datura stramonium), black henbane, horse nettle, and tobacco. They contain several alkaloids, with the most problematic being solanine. Their toxicity varies depending on the plant and growing conditions.
Goats are more inclined to eat the stems and leaves than the fruit, which is the most toxic part of the plant. They’re less likely to be affected than pigs or horses, and often, ingestion isn’t fatal but can be. Be careful not to give goats too many cuttings when pruning or removing these plants from your garden, and check your pasture for horse nettles or other invasive nightshades.
Rattleweed/Rattlebox
These legumes, in the genus Crotalaria, were used in the southeast to fix nitrogen in fields and, over time, spread as volunteers. They contain the PAs crotaline and monocrotaline. The plants aren’t generally palatable to goats, so they only become problematic when other food isn’t available. All parts are poisonous, with the highest concentration in the seeds.
The tall plants have hairy underleaves and yellow flowers and produce hairless, black pods that contain 10 to 20 seeds. The seeds come loose and rattle, giving the plant its name.
Yew
This common landscaping plant contains 10 or more poisonous alkaloids, with taxine being the most toxic. Seeds, needles, bark, and leaves — even when dried — are all poisonous, with seeds having the highest concentration. The most common poisoning occurs when pruned leaves or branches are fed to goats. Two reports in the 1990s found large quantities of yew leaves in the rumens of goats found dead, with branches in the feeder.
Yews are evergreen trees or shrubs, with the thin, pointed leaves of most evergreens. They produce single-seeded red or yellow berries.
It’s unknown whether the toxins are passed through milk to humans, but milk from a surviving doe should be avoided for at least two days after poisoning. Death can occur as quickly as two hours after ingestion of the branches, and once symptoms are present, death is usually imminent.
Boxwood (Buxacea)
Little is written on goat poisoning by this popular ornamental shrub, although it’s known to be toxic to other livestock. Bark and leaves, which contain triterpenoidal alkaloids, are the most poisonous parts of the plant. It can cause gastroenteritis with diarrhea and even death — usually by respiratory failure when a large amount is consumed.
Boxwood is a compact woody shrub with many branches covered by dark green, leathery leaves. The flowers are lighter green and star-shaped.
Poison and Water Hemlock
These invasive noxious weeds in the parsley family are found throughout North America. Poison hemlock prefers fields, ditches, and roadsides. Water hemlock is found on the edges of creeks and other bodies of water and is more deadly. The plants contain poisonous piperidine alkaloids, including coniine and gamma-coniceine. Gamma-coniceine is the more toxic of the two and is found in immature plants.
Animals that consume a large amount may initially be stimulated and then show nervous system effects. Seizures are common. Signs of poisoning can occur within an hour of eating the plant. Poison hemlock is also known to cause birth defects in sheep, even when small amounts are consumed, although sheep are more tolerant to it than cattle.
The plants look similar and are tall, with hollow stems, white flowers, and a taproot that resembles a carrot. They’re often mistaken for wild carrot, also known as Queen Anne’s Lace. A couple of ways to tell the difference are in the stems and smell. Queen Anne’s Lace has a hairy stem and smells like carrot if crushed. Poison hemlock has a smooth, hollow stem with purple blotches and smells unpleasant when crushed.
Mayapple, Bloodroot, Pokeweed, and Hellebore
These plants also contain poisonous alkaloids, but goats rarely eat them unless they’re starving.
CHERYL K. SMITH has raised mini dairy goats in the Coast Range of Oregon since 1998. She owns Karmadillo Press and is the author of Raising Goats for Dummies, Goat Health Care, Goat Midwifery, and Shed Boy, the first in a series of cozy mysteries set on a goat farm. www.GoatHealthCare.com
References:
- Anholt, H., and A. Britton. 2017. “Presumptive chronic pyrrolizidine alkaloid poisoning in 2 pygmy goats due to ingestion of tansy ragwort (Jacobaea vulgaris) in southwestern British Columbia.” Can Vet J 58(11):1171–1175. pmc.ncbi.nlm.nih.gov/articles/PMC5640293/
- Bates, N. 2022. “Plant poisoning in goats.” UK-Vet Livestock 20(4). ukvetlivestock.com/content/clinical/plant-poisoning-in-goats/
- Knight, Anthony P, and Richard G. Walter. 2001. A Guide to Plant Poisoning of Plants in North America. Jackson, Wyoming: Teton NewMedia.
- Lisanka, AM, et al. 2013. “Natural and experimental poisoning of goats with the pyrrolizidine alkaloid–producing plant Crotalaria retusa L.” J Vet Diagnostic Investigation 25(5) 592–95. journals.sagepub.com/doi/pdf/10.1177/1040638713495544
- Lau, Elisabeth M. “Poison Hemlock Toxicity in Goats and Sheep.” comstockequine.com/storage/app/media/Documents/POISON_HEMLOCK_TOXICITY_IN_GOATS_AND_SHEEP.pdf
- Smith, Mary C, and David M Sherman. 2009. Goat Medicine, 2nd ed. Ames, Iowa: Wiley-Blackwell.
Originally published in the May 1, 2025 digital issue of Goat Journal
