Poisonous Plants and Livestock

poisonous plants livestock

A couple of weeks ago I visited a poisonous plant garden. No, it wasn’t at Hogwarts. It was at the University of Illinois. Don’t go looking for it. You won’t find it. It is hidden away behind the school of veterinary medicine. Since the plants are poisonous, they don’t want people taking self-guided tours and potentially poisoning themselves.

Our tour was coordinated by The Land Connection and led by Dr. Michael Biehl, clinical professor of toxicology at the vet school. I was hoping to learn about what poisonous plants are really dangerous to goats because I’ve never seen an accurate list, but unfortunately the professor did not have a lot of experience with goats. That’s why this post is not entitled “Poisonous plants and goats.” One thing that was repeated often was “the dose makes the poison.” I knew that, but I had no idea how many plants in the pasture are technically poisonous.

Lamb Quarters

lambs quarters
Lambs quarters

For example, lambs quarters, which some people call wild spinach, contains nitrates and oxalates. I was really surprised to hear this because I have eaten lambs quarters. It grows wild on our farm. Too much of it, however, can cause “headache, flushing skin, vomiting, dizziness, and reduced blood pressure” according to the handout we were given. I know our goats, sheep, and cattle eat this because it grows all over our farm, but no one has ever gotten sick.

Coming home and searching online just confused me even more because the vast majority of info out there talks about how it’s edible and even medicinal, such as this interesting post. According to this article, the oxalic acid is neutralized when cooked, just like spinach, however, I’ve eaten it raw, so I still have questions.

Corn and Soybean Plants

Corn and soybean plants were also listed as poisonous. Both contain nitrates, and soy is a protease inhibitor, which can cause diarrhea, vomiting, tremors, difficult breathing, and convulsions.

Corn may have dangerously high levels of selenium, as well as mycotoxins when moldy, but I know plenty of farmers let cattle graze on corn stubble in the fall.

The green foliage and unripe fruit of ground cherries, which also grow wild on our farm, contain solanine and atropine-like alkaloids, which can cause “CNS depression, rapid respiration, nausea, diarrhea, muscle weakness, paralysis.” I think our sheep may be smart enough to avoid these, or they don’t eat many, because I see a lot of these in our sheep pasture, even when sheep have been in a pasture for awhile and we’re rotating them out to greener pastures.

Grass Seeds

Another bit of information I found interesting is that many grass seeds can have a toxic fungus on them called ergot, which is another reason it’s not a great idea to let your pasture grasses go to seed. (Grasses are also not as nutritious or tasty after going to seed.) We have grass going to seed every year, but this has never been a problem on our farm. And it’s tempting to not even mention it.

However, recently someone on a Facebook group had a goat that died from apparent poisoning, and she couldn’t figure out what it could have been because there was nothing new in her pasture. Unfortunately I don’t remember the person who posted or even the group, but I wonder if she may have had some grass that had gone to seed.

You can see the fungus on the seed, if it’s there. Ergot poisoning affects cattle most often, so even if the fungus is present in grass seed in your pasture, it may not be a problem with sheep and goats. Or it might only affect one or two, rather than everyone. If you click on that link, you can see a seed head that has ergot fungus on it. It’s the dark brown specks.

The Dose Makes the Poison

Like everything else in veterinary medicine, most of the info on poisonous plants focuses on dogs, cats, and horses. Those of us with sheep, goats, and pigs are really on our own. Sheep and goats are minor species, and since commercial hogs are now raised in confinement, the risk of plant poisoning is non-existent because they have no contact with living plants. However, black-eyed susan was listed as possibly causing comas in swine.

Confused yet? Are you wondering why I even bothered writing a blog post with so little actionable information? Shortly into the garden tour I was wondering if I’d wasted several hours driving down there and attending, but I did ultimately pick up some good tips, even though I don’t have an accurate list of poisonous plants that you need to eliminate from your pasture. These two points explain a lot …

  1. The dose makes the poison.
  2. The solution to pollution is dilution.

Bottom line is that there are a lot of plants out there that contain poisonous components, many of which we eat, such as spinach, beets, and peanuts, which are high in oxylates. So, if you ate nothing but that one food, you might not feel too great.

But we don’t do that. We eat a variety of foods, and so do pastured livestock. So, as long as the dose isn’t huge, and as long as they’re eating a lot of other foods, you are unlikely to have a problem with some plants that are technically poisonous.

Goat Poisoning Story

This reminds me of one of the only goat poisoning stories I’ve ever heard. A woman who was a member of my goat group several years ago had goats in a pasture with oleander, which is one of the most toxic plants known to science. They appeared to avoid it and were fine for months, but when everything else in the pasture was eaten down, several of them got sick, and at least one of them died. So, that’s another thing to keep in mind — when animals have options, some may be smart enough to avoid poisonous plants (or not eat enough to make themselves really sick).

What’s the bottom line on poisonous plants?

If you have horses or cattle, the lists of poisonous plants seem to be pretty accurate. However, for those of us with other livestock, we would be whacking down and digging up a lot of plants unnecessarily, if we followed the advice on those lists.

Another thing I learned is that horse owners are not picky about their hay for no reason. Horses seem to be more sensitive to poisonous plants than other livestock, which is why owners prefer hay without weeds.

My advice for those of us with sheep, goats, and pigs has been to ask other owners in your area which plants are poisonous. For example, maple and oak leaves are often listed as poisonous, but our farm is called Antiquity Oaks because it’s covered with burr and white oak trees, and our goats have eaten oak leaves when green and brown and as buds, and no one has ever had a problem.

We also have a lot of maple trees, which have never been a problem.

I will remain on the lookout for an accurate list of poisonous plants for goats, and I’ll let you know when I find one. If you have one that’s accurate, please post in the comment section below!

For more information

Check out podcast episode #46 – Healthy Weeds and Poisonous Plants, where I’m talking to Kim Cassida from Michigan State University. We talk about the fact that many weeds can actually be very nutritious for goats while the number of plants poisonous to goats is actually pretty low. 

Poisonous Plants and Livestock Pinterest Image

28 thoughts on “Poisonous Plants and Livestock”

    • Oh, my, this makes my head spin!

      I know for certain the top reason horse owners are so concerned about potential poisoning is because horses physically are unable to vomit and will die rapidly if poisoned. Thankfully, goats can vomit.

      Most of the goats I’ve owned have gotten into rhododendron — which, as everyone knows, is deadly poison within hours. My first experience with this was when I came home to goats throwing up all over themselves and each other like it was a pay-per-view barf show, and found rhody leaves generously heaped over the fence. (The mystery was eventually solved: it was the work of a thoughtful human.) Racing against the clock, I obtained enough charcoal to dose them all and went at it with heartsick desperation. It worked. The next year new goats tried the same trick with rhodies that the neighbor had, just that day, planted along the back fence. Charcoal to the rescue again. Funny thing is, the goats who have tried it once have never tried it again.

      We also have buttercup, digitalis, and poison hemlock. I have faithfully removed the poison hemlock, but the digitalis I have left since they rarely forage in that area (it’s outside their pen) and they always leave it alone. The buttercup is something they always ignore, no matter how hungry they have been to date.

      One poisonous plant we have that they consume great gobs of with gusto is Carolina Laurel Cherry. Seriously!? I don’t understand.

      • Thanks for sharing that. I’d have thought that rhododendron would have killed them for sure. Glad to know the charcoal helped.

      • I have been looking for the same sort of list as I wish to raise a few sheep for the freezer. I have contacted the local extension office and they kindly replied I did not give them enough information. Would have appreciated someone driving the 12 miles to my property to check out my pastures. Maybe they want me to bring in a sample of everything growing out there.

    • Our first goat was from a rescue farm that I used to volunteer at. (My place got so big that I didn’t have time to volunteer anymore ) Tippy’s mom died in childbirth and I raised him. Needless to say, we had to eventually get him a goat friend as he was beginning to think he was dog/human. So, I brought Timmy home from the farm one day. The previous owners had planted azaleas, and although instinctively they left them alone, one day my husband was doing yard work and they were playing around him. He had piled up cuttings of the trees and bushes he was trimming, which included the azalea cuttings. They of course took advantage of the easy pickin’s. Next thing I know, Timmy is barfing, and let me tell ya, if you have never experienced a goat throwing up, it’s stuff out of a horror movie! All over me, the walls, the ceiling (they still lived inside mostly) I called every vet I knew and was able to pick up enough charcoal to save his life, but I was really scared we would lose him. He’s 7 years old this year, thank God, and one of the sweetest wethers…he’d make a good therapy goat. Needless to say, all azaleas including the roots were cut down, pulled out, and burned with a vengeance. I pulled up one of the, I’m sure, incomplete lists and azaleas were on there…nothing else in that pile was, so I was sure it was the culprit. Haven’t had a problem since.

      • Azaleas are one of those plants that are poisonous to pretty much every living creature, so it wouldn’t surprise me that they made goats sick.

  1. The good news is that plants can communicate with animals to a significant degree. Things that are poisonous typically taste bitter or otherwise unpalatable. Not always true but usually. My mother, a doctor, first told me this. Over the decades I’ve observed that she is correct. Unless starved grazing animals avoid the toxic plants in their fields. We graze about 400 pigs on pasture. If I want them to knock down the weeds I mob an area lightly. Most non-graze forages don’t handle the hoof traffic well so this turns the pasture towards forages I want.

  2. This may be a stupid question but how was the charcoal given? Was it liquid form? Just in case I may need it sometime I want to hVe it on hand.

  3. Colorado State University has a terrific area on their website about poisonous plants. Lots of pictures and descriptions of symptoms. Visiting a garden like Deborah did is a fabulous way to learn to recognize the plants.


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