From mild gastrointestinal upset to more severe symptoms, even death, poisonous plants can be toxic to livestock. Learning to recognize these plants and properly manage animals and pastures is critical to ensuring the safety of horses and cattle. On this archived episode of Animal Airwaves Live, Dr. Chris Martyniuk, a professor of toxicology, discusses how you can better educate yourself about situations and locations where plant toxicity is the most threatening to livestock, some of the worst plant culprits, and what to do if you suspect your animal has ingested a poisonous plant.
Transcript:
DANA HILL: From WUFT-FM, this is Animal Airwaves Live, our weekly hour long show devoted to the discussion of the health and welfare of animals on Dana Hill.
DANA HILL: Happy you could tune in here on this Friday, June 14, 2024.
DANA HILL: And happy to welcome back to the program today from the University of Florida College of Veterinary Medicine, our friend Dr. Chris Martyniuk.
DANA HILL: And we’re going to be talking today about how to keep horses and cows safe from poisonous plants.
DANA HILL: It’s not hard to imagine these are animals that are out there grazing in open fields.
DANA HILL: Things grow maybe where we wouldn’t like them to grow and they become the food for these animals.
DANA HILL: We’re going to find out how to keep them safe.
DANA HILL: Stay tuned.
DANA HILL: Animal Airwaves Live is coming up after this news from NPR.
DANA HILL: From WUFT, this is Animal Airwaves Live, our weekly hour long show devoted to the discussion of the health and welfare of animals.
DANA HILL: I’m Dana Hill and I’m happy to welcome you here on this Friday, June 14, 2024.
DANA HILL: And happy to welcome back to the program today our friend from the University of Florida College of Veterinary Medicine, Dr. Chris Martyniuk.
DANA HILL: And we’re going to be talking today about keeping horses and cows safe from poisonous plants, these plants that may be not just in our yards and gardens, but in pastures and fields and places where these animals graze.
DANA HILL: So let me welcome you back to the program.
DANA HILL: Dr. Martyniuk, it’s good to see you again.
CHRIS MARTYNIUK: Yes, thank you for having me back, Dana.
CHRIS MARTYNIUK: Nice to see you.
DANA HILL: Well, horses and cows are an economically important animal here in Florida in a lot of places.
DANA HILL: So it’s understandable that in addition to just their own welfare and our care and compassion for them as living things, we would want to keep them safe from harm as best we can.
DANA HILL: Harm that might include toxic and poisonous plants.
DANA HILL: First, I guess maybe a good place to start is there a difference between toxic and poisonous?
DANA HILL: Should we use one word versus the other?
CHRIS MARTYNIUK: Yeah, it’s a good question.
CHRIS MARTYNIUK: So I think in this case they can be used interchangeably.
CHRIS MARTYNIUK: A lot of plants do produce compounds that can be toxic/poisonous to livestock.
CHRIS MARTYNIUK: They do this really as a defense mechanism against grazing and also against pests.
DANA HILL: So these plants do not want to be consumed.
DANA HILL: Is that basically what’s happening here?
CHRIS MARTYNIUK: Pretty much.
CHRIS MARTYNIUK: So it’s an arms race really between the livestock and the plants, and the plants they can’t move around, so they come up with other ways to defend themselves and they do that through chemicals.
DANA HILL: So I mean, this is natural selection at work here, right?
DANA HILL: This is evolution Kind of manifest these plants that, as you say, they can’t really easily, at least in their own lifetimes, go anywhere, but over time, they have adapted to resist those creatures that would end or shorten their lives.
CHRIS MARTYNIUK: Exactly.
DANA HILL: So, I mean, how.
DANA HILL: I realize that you’re a veterinarian and maybe not a botanist, but how does this all work?
CHRIS MARTYNIUK: So in terms of how the plants are producing the chemicals, I know that when plants are ingested or grazed upon, a lot of times that’s when they release a lot of these chemicals that are sequestered inside of the plant.
CHRIS MARTYNIUK: Other plants are producing these compounds fairly regularly as a defense mechanism.
CHRIS MARTYNIUK: And once the poison gets into the livestock, that can wreak havoc on many different organ systems.
CHRIS MARTYNIUK: Of course, first the gastrointestinal system.
CHRIS MARTYNIUK: But once those poisons, toxins are absorbed, they can be circulated throughout the body.
CHRIS MARTYNIUK: And different plants have different toxins that affect different organ systems.
DANA HILL: Now, we have spoken before on this program about the kinds of plants that may be in our own living environment where we choose to dwell and raise our families and keep our pets.
DANA HILL: And these are sometimes quite common plants in our landscape, like sago palms or oleanders.
DANA HILL: And those, as we know from this program, can have pretty nasty effects on animals that may consume them, presumably people, too, but don’t eat oleander and sago palm.
DANA HILL: So these, we have learned from these episodes in which we talked about that, that consuming these can really do a number on the inside of animals.
DANA HILL: And there are then, I gather, plants that can grow out in pastures and fields where we have grazing animals that can similarly cause distress and illness for.
DANA HILL: For animals like horses and cattle.
CHRIS MARTYNIUK: Yes, exactly.
CHRIS MARTYNIUK: And I know previously on the show, we’ve talked about different plants, ornamentals, like you mentioned, that are toxic to small animals, not surprisingly, larger animals and smaller animals, companion animals, they have very different plants that they are exposed to and affected by.
CHRIS MARTYNIUK: One of the more common exposure scenarios for livestock is what you mentioned, the growth of weeds in unkept farmland that eventually the livestock will ingest and could potentially exert exposure and toxicity to that.
DANA HILL: Individual cattle is the cattle forms a pretty large, economically significant enterprise in the state of Florida.
DANA HILL: There are, you know, I don’t know how many thousands of cattle that are kept in Florida, but large operations that you think of, when you think about cattle operations, you think about these feedlots and you think about cattle that probably aren’t grazing very much, but instead are fed in troughs and whatnot.
DANA HILL: But we’re going to be largely talking today about these animals that might actually be out in the field.
DANA HILL: And this would include lots of horses, because, of course, horses spend a lot of time in pastures.
DANA HILL: And even if they are being cared for and babied in barns and stalls where they’re getting all of their nutritional needs met kind of by human beings who provide them nutritious and balanced food, while out in the pasture, they still are going to nibble around.
DANA HILL: Are there similar plants that cause distress to both cattle and horses?
DANA HILL: And you mentioned earlier that, you know, the plants are they.
DANA HILL: Can they be different from the ones that would affect small animals?
DANA HILL: That is to say, are there plants that small animals would find poisonous that large animals would not?
CHRIS MARTYNIUK: Yes, to some extent.
CHRIS MARTYNIUK: And it’s mostly due to exposure.
CHRIS MARTYNIUK: So the differences really arise from the types of plants that small animals are exposed to, like the household ornamentals.
CHRIS MARTYNIUK: They might not be exposed to weeds that grow in a feedlot, for example.
CHRIS MARTYNIUK: But getting to your question about differences, even amongst horses and cattle, there are different plants that cause toxicity to those two different species.
CHRIS MARTYNIUK: One example I can think of is red maple.
CHRIS MARTYNIUK: So red maple, ubiquitous in Florida, very popular tree, you know, we have in our yard.
CHRIS MARTYNIUK: We don’t have horses around, thankfully, but very, very toxic to horses, not so much cattle.
CHRIS MARTYNIUK: And what it does in horses is it causes oxidative stress of the red blood cells.
CHRIS MARTYNIUK: So basically, the animals are unable.
CHRIS MARTYNIUK: The horses are unable to carry oxygen anymore.
CHRIS MARTYNIUK: So red maple is very dangerous and toxic to horses, but not so much cattle.
DANA HILL: That’s really fascinating.
DANA HILL: Now, can we talk about maybe here at the top of the show, any differences between the digestive systems of horses and cattle?
DANA HILL: Are they.
DANA HILL: Are they similar?
DANA HILL: Because they’re kind of large grazing animals.
CHRIS MARTYNIUK: So horses are considered to be monogastric and the cattle are considered to be ruminants.
CHRIS MARTYNIUK: They have more chambers in their stomach.
CHRIS MARTYNIUK: So that is a huge difference.
CHRIS MARTYNIUK: That kind of mediates toxicity.
CHRIS MARTYNIUK: There are other toxicants that might affect cattle more because of the unique microbiome.
CHRIS MARTYNIUK: It can convert some of these poisonous plant compounds into more toxic agents?
DANA HILL: Oh, no.
CHRIS MARTYNIUK: Yes.
DANA HILL: So the cattle’s body is doing itself a disservice then.
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: And one good example I can give you is in the case of a toxicity called 3-methylindole.
CHRIS MARTYNIUK: And what happens there is that the cattle are released onto green pasture, which you would assume would be a great idea.
CHRIS MARTYNIUK: But if they’re released onto pasture too quickly and don’t have time to adapt to this lush green pasture, what happens is they ingest a lot of grass.
CHRIS MARTYNIUK: And that lush green grass can contain an amino acid called L-Tryptophan and actually the microbiota of the ruminant transforms that tryptophan into a toxic compound called 3-methylindole that actually travels to the lungs of the cow and causes respiratory distress.
CHRIS MARTYNIUK: So there’s a disease associated with that toxicity.
DANA HILL: Why have I heard of tryptophan before?
CHRIS MARTYNIUK: Tryptophan is a ubiquitous amino acid.
CHRIS MARTYNIUK: We get that in food.
CHRIS MARTYNIUK: And it’s also a precursor to a neurotransmitter called serotonin.
DANA HILL: Is it why I’m so sleepy after Thanksgiving?
CHRIS MARTYNIUK: Exactly.
DANA HILL: Okay, so I would have.
DANA HILL: Here’s why.
DANA HILL: I would be a terrible cowboy.
DANA HILL: I guess I would have just thought, hey, let these animals out in this lush green pasture.
DANA HILL: Go for it.
DANA HILL: What kind of grasses and plants in Florida kind of exist that these animals can safely eat?
DANA HILL: I think about the kinds of grass that I see in neighborhoods.
DANA HILL: Is that markedly different than what you might find in pastures?
CHRIS MARTYNIUK: Yeah, it can be.
CHRIS MARTYNIUK: There’s types of different grasses that are grown out on pasture.
CHRIS MARTYNIUK: Really, that issue I talked about with the 3-methylindole is related to very, very green pastures.
CHRIS MARTYNIUK: It really depends on the type of grass, like you mentioned, how much of these compounds are being produced at the time.
CHRIS MARTYNIUK: One recommendation for farmers is to rotate their cattle or really give them time to adapt to lush green pastures.
CHRIS MARTYNIUK: So don’t leave them on pasture for hours on end where they can ingest high levels of these compounds.
CHRIS MARTYNIUK: So it’s a little, you know, a little bit of watch and wait and see how the cattle respond to these types of grasses.
CHRIS MARTYNIUK: But another type of grass that I can think of too, very popular for agriculture is tall fescue, which is a popular grass for sheep and for cattle.
CHRIS MARTYNIUK: And the problem with tall fescue is that they can contain what’s called an endophyte that lives inside the grass that produces some toxic compounds called ergot alkaloids.
DANA HILL: Okay, well, you’re going to have to help me understand what is so bad about those, besides the name being kind of scary.
CHRIS MARTYNIUK: Sure, yeah.
CHRIS MARTYNIUK: So these ergot alkaloids are compounds that are very similar to LSD, and so they cause very similar effects in livestock.
CHRIS MARTYNIUK: With the hallucinations, there’s restricted blood flow, There can be necrosis of the extremities.
CHRIS MARTYNIUK: And it’s been a real problem for livestock throughout the country if they’re exposed to these ergot alkaloids.
DANA HILL: I would invite listeners to just pause for a moment and think about the kind of consciousness of some sort of grazing animal and what sort of things they might hallucinate about it could potentially be a nightmare.
DANA HILL: I hope, though, it’s nice, but the preventing them from having that.
DANA HILL: This is not something anybody wants to happen.
DANA HILL: You know, I start to think about the strategies that folks might employ to mitigate these dangers.
DANA HILL: And other than plowing into dirt everything and then starting fresh, what can you do?
CHRIS MARTYNIUK: That’s a good question.
CHRIS MARTYNIUK: So unlike, I think, some of the toxicants and companion animals, really the main thing that you can do is be vigilant about what is growing on your fields and really preventing the animals from ingesting those types of plants.
CHRIS MARTYNIUK: Sometimes the animals will seek out toxic plants because they like the taste.
CHRIS MARTYNIUK: And it becomes very challenging to be on your field and trying to identify all the potential sources of toxicosis.
DANA HILL: Well, okay, so now I think about how these plants have adapted themselves in order to be poisonous or toxic to animals and would not have a better strategy than to simply taste terrible.
DANA HILL: You’d save yourself a lot of trouble.
DANA HILL: Now, let’s kind of get into some specifics here.
DANA HILL: And I don’t know if it’s helpful to go kind of animal by animal, but if we look at sort of the systems in the body in which toxicity can rear its head, there’s a whole host of symptoms.
DANA HILL: Right.
DANA HILL: I mean, you mentioned something that can kind of deprive the blood of oxygen.
DANA HILL: Yes, well, I mean, that’s one way, but there’s also other organs like the liver, there’s kidneys, there’s the neurological components of all of this.
DANA HILL: Can all of these be affected by different chemicals?
CHRIS MARTYNIUK: Yes, eventually.
CHRIS MARTYNIUK: So what I will say is that for many of the plant toxicants, what plants have done over their evolutionary time period is really focused on organ systems that are specific to animals and not plants.
CHRIS MARTYNIUK: They don’t want to harm themselves, so they’ll create chemicals that might impact the heart or the brain, things that plants don’t have, of course.
CHRIS MARTYNIUK: And many of these toxicants can be specifically acting on those tissues.
CHRIS MARTYNIUK: But over time, there can be systemic failures in the animal that kind of lead to more systemic organ failure.
CHRIS MARTYNIUK: But many of the toxicants do have kind of specific mechanisms of action or specific sites where they wreak the most havoc.
DANA HILL: If you were a plant, what would be the best strategy?
DANA HILL: Would you be very potent and rapidly toxic, or would you be gradually toxic but in a sort of cumulative way?
CHRIS MARTYNIUK: That’s.
CHRIS MARTYNIUK: Yeah, great question.
CHRIS MARTYNIUK: If I were a plant personally, I’d want something to be very potent, very toxic, very quick.
CHRIS MARTYNIUK: Because the longer that animal is ingesting me, the more damage it’s going to do so, that is one strategy.
CHRIS MARTYNIUK: And again, to attack organs like the heart and the central nervous system are very effective ways to be very direct and fast acting.
CHRIS MARTYNIUK: So maybe something like the liver or kidney, it would take a longer period of time for the animal to succumb to those types of injuries.
CHRIS MARTYNIUK: That being said, plants are very different.
CHRIS MARTYNIUK: And so some plants, like clover, have come up with a different strategy.
CHRIS MARTYNIUK: Sheep will ingest clover.
CHRIS MARTYNIUK: And one strategy that clover has is to produce what’s called phytoestrogens or these estrogenic, like chemicals that disrupt the reproductive system of sheep.
CHRIS MARTYNIUK: And so over time, the sheep can’t reproduce because they’re eating the clover.
CHRIS MARTYNIUK: And this is great for the clover because now we don’t have offspring that’s going to eat us later on.
DANA HILL: Yeah, but I mean, if you’re a clover, that’s a real long game.
CHRIS MARTYNIUK: But think about clover and how much of it is in a field.
CHRIS MARTYNIUK: Yeah, you’re not talking about one tree, you’re talking about a field of clover.
CHRIS MARTYNIUK: So different strategies for different plants.
DANA HILL: So when I think about clover, it’s ubiquitous.
DANA HILL: You go outside almost anywhere and you can find it usually.
DANA HILL: And while I’ve never been compelled to eat it myself, it’s very lush and green.
DANA HILL: It’s often the greenest thing around.
DANA HILL: And it’s got, you know, the little leaves, it’s got these little flowers.
DANA HILL: Are all parts of it toxic?
CHRIS MARTYNIUK: Not all parts.
CHRIS MARTYNIUK: I mean, to some extent.
CHRIS MARTYNIUK: So I think clover is fine for livestock to ingest, but once the feeding becomes too intense and the plant feels that pressure of plants can feel they will produce more of these compounds.
CHRIS MARTYNIUK: So it’s kind of again, this push pull with the organisms.
CHRIS MARTYNIUK: If there’s intense grazing, clover will start to produce higher levels of these estrogens to combat that.
CHRIS MARTYNIUK: High intensity grazing.
DANA HILL: Wow.
DANA HILL: Okay, so I guess if we’re gonna talk about some of the systems in the body, then where is a good place to start?
DANA HILL: Because you mentioned that something like the liver might take a little bit longer to become potentially dangerous for this animal.
DANA HILL: But.
DANA HILL: All right, well, let us start there anyway.
DANA HILL: What kind of plants that animals might be exposed to can have negative effects on the liver.
CHRIS MARTYNIUK: Yeah, and just to back up a little bit with the liver, so I think it’s an interesting organ.
CHRIS MARTYNIUK: It’s a massive organ.
CHRIS MARTYNIUK: It’s known as the detoxifying organ in the body.
CHRIS MARTYNIUK: So many of the chemicals really end up in the liver and that’s where they’re metabolized and broken down for excretion.
CHRIS MARTYNIUK: In terms of plants that directly affect the liver.
CHRIS MARTYNIUK: I would include ragwort as one of those plants, and one that we have here in Florida quite a bit is rattlebox.
CHRIS MARTYNIUK: Those are the little seed pods that you can shake.
CHRIS MARTYNIUK: They have very beautiful yellow flowers.
DANA HILL: I’m going to look up some of these as you mention them, because.
CHRIS MARTYNIUK: Yeah, crotalaria is the name of the genus, but also known as rattlebox.
CHRIS MARTYNIUK: And these plants produce some pretty nasty compounds.
CHRIS MARTYNIUK: It’s a mouthful.
CHRIS MARTYNIUK: They’re called pyrrolizidine alkaloids, and they cause damage directly to the liver.
CHRIS MARTYNIUK: But what’s interesting is that that damage takes months and months and months to accumulate to a point where the liver actually fails.
CHRIS MARTYNIUK: So it’s kind of a chronic toxicity.
CHRIS MARTYNIUK: And unfortunately, farmers don’t know it’s happening until their livestock just succumb to the toxicosis and there’s a mortality event.
DANA HILL: Well, it seems to me that with that plant at least you can be made aware of its presence because it can flower, right?
CHRIS MARTYNIUK: It does, yes.
DANA HILL: Maybe that would help you identify it.
DANA HILL: But some of these plants may be a little bit less apparent.
DANA HILL: And with that one in particular, it might not even just be grazing animals.
DANA HILL: That could potentially be dangerous to some other animals as well.
CHRIS MARTYNIUK: It can, yeah.
CHRIS MARTYNIUK: Wildlife can be exposed to those plants, too.
DANA HILL: Would it require, though, a great deal of hunger?
DANA HILL: Would these be animals that are stressed for other sources of food that would choose to turn to something like that?
CHRIS MARTYNIUK: That can definitely promote toxicity.
CHRIS MARTYNIUK: So if the animals are hungry or have been underfed, just not enough nutrients, they might turn to these types of weeds and plants and start to ingest them.
DANA HILL: Okay, another yellow flower, I think ragwort.
DANA HILL: Is that the ragworts?
CHRIS MARTYNIUK: Yes.
DANA HILL: Yeah.
DANA HILL: I mean, those.
DANA HILL: They have effects on the liver, but again, it takes a while for it to accumulate in the system.
CHRIS MARTYNIUK: Yes.
CHRIS MARTYNIUK: So these plants have the same types of compounds, these pyrrolizidine alkaloids that do take time to damage the liver.
DANA HILL: Okay, now you mentioned that the liver as an organ primarily responsible for ridding the body of toxicants.
DANA HILL: Can you describe how it does that?
DANA HILL: It’s totally fascinating.
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: So, I mean, once a plant is ingested and it’s producing these toxic chemicals, they can eventually be absorbed through the gastrointestinal system.
CHRIS MARTYNIUK: They’ll eventually enter the blood circulation, and they’ll soon make their way to the liver.
CHRIS MARTYNIUK: The liver is, again, that detoxification organization, and it contains high levels of enzymes that detoxify certain compounds.
CHRIS MARTYNIUK: I think, you know, that’s why humans and animals have such large livers compared to Other organs, just through, you know, centuries of battling toxins and plants and animals.
CHRIS MARTYNIUK: You know, we need a big organ to detoxify all the different chemicals that could potentially harm us.
CHRIS MARTYNIUK: So it breaks down the chemical, and the chemical is eventually excreted through the urine or through the feces and leaves the body safely.
DANA HILL: Now, there are plenty of things that we ingest that, absent the liver, could cause us real problems.
DANA HILL: But the liver does its job.
DANA HILL: And the same is probably true for horses and cattle.
DANA HILL: But again, there are some that the liver is just not well equipped to handle.
DANA HILL: And if it can’t handle those, well, that is to say, is the problem in that it can’t filter them out, for lack of a better word, or that it can’t excrete them.
DANA HILL: Can it just not tolerate them or can it not excrete them?
DANA HILL: And so they just accumulate?
CHRIS MARTYNIUK: Yeah, very good question.
CHRIS MARTYNIUK: And I think the answer is all of it.
CHRIS MARTYNIUK: So some chemicals can eventually not be broken down and they accumulate.
CHRIS MARTYNIUK: Some the liver can’t handle, and they keep circulating in the blood and cause damage to other tissue.
CHRIS MARTYNIUK: One interesting kind of exposure scenario is the ingestion of some plants that are photosensitizers.
CHRIS MARTYNIUK: So when the liver is damaged, it can’t excrete plant material like the chloroplasts and the phylloerythrin.
CHRIS MARTYNIUK: Those circulate in the blood and actually will cause sunburns in the animal because the liver is nonfunctional.
CHRIS MARTYNIUK: So that’s called secondary photosensitization.
DANA HILL: Hold on.
DANA HILL: Now, these are animals that are covered in fur pretty much everywhere.
CHRIS MARTYNIUK: Yep.
CHRIS MARTYNIUK: So they can get sunburns.
CHRIS MARTYNIUK: And these chemicals, if they’re not excreted because the liver fails, then these compounds reach the skin, and with UV light, there’ll be a reaction, and the animal will end up with a pretty severe sunburn.
CHRIS MARTYNIUK: And that can lead to infection and other issues.
DANA HILL: Well, and also, sunburns are just the worst.
DANA HILL: And these are animals that are spending countless hours in total full sun all the time.
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: And the treatment for that kind of a scenario is to get the animal out of the sun into a dark shed and just keep the animal calm.
CHRIS MARTYNIUK: And you might need to administer antibiotics for skin blemishes and wounds and corticosteroids, things of that nature.
DANA HILL: Now, what sort of plants can cause that sort of problem?
CHRIS MARTYNIUK: So in terms of the secondary photosensitization, one big offender is lantana, which we have here in Florida all over the place, both ornamental and in the wild.
DANA HILL: And is it a native plant?
DANA HILL: Because I do see it all over the place.
CHRIS MARTYNIUK: So it’s not endemic here, but it has invaded and it’s established itself here.
CHRIS MARTYNIUK: So it’s a tropical plant.
DANA HILL: Yeah, you’ve seen this, dear listener.
DANA HILL: You’ve seen it all over the place.
DANA HILL: And I have it.
DANA HILL: Gosh, I have it at my house too.
DANA HILL: And it’s got different color flowers.
DANA HILL: You can get them in different colors.
DANA HILL: My recollection is they don’t smell great, but butterflies like them.
CHRIS MARTYNIUK: Yes.
DANA HILL: And I wouldn’t have probably thought anything of it, but I’ll keep my, my grazing livestock away from it.
CHRIS MARTYNIUK: Yeah, that plant will damage the liver and then that leads to the secondary photosensitization or the sunburn.
CHRIS MARTYNIUK: So.
DANA HILL: But does it require a lot of ingestion?
DANA HILL: Right.
DANA HILL: I mean, because this is one of those things where how toxic something is depends on how much you consume.
CHRIS MARTYNIUK: Exactly.
CHRIS MARTYNIUK: Yes.
CHRIS MARTYNIUK: And we are talking in terms of that plant.
CHRIS MARTYNIUK: You do need to eat a significant amount.
CHRIS MARTYNIUK: It’s usually a problem with the larger animals.
CHRIS MARTYNIUK: You would never see a cat or a dog ingest enough lantana to really elicit that reaction.
DANA HILL: But one can imagine a cow or horse leaning its head kind of over the fence because this stuff is just growing freely like, you know, outside of the pasture.
DANA HILL: And if maybe if, you know, other food sources seem a little bit more scarce, if the grass has already been chewed down pretty low, maybe lantana is where you go.
CHRIS MARTYNIUK: Yep.
DANA HILL: All right.
DANA HILL: Well, we’re kind of just getting started, but I want to remind listeners that this is Animal Airwaves Live here on WUFT-FM, our weekly hour long show devoted to the discussion of the health and welfare of animals.
DANA HILL: I’m Dana Hill.
DANA HILL: My guest from the UF College of Veterinary Medicine is Dr. Chris Martyniuk.
DANA HILL: We’ll be back with more after this.
DANA HILL: Stay tuned.
DANA HILL: Welcome back to Animal Airwaves live here on WUFT-FM.
DANA HILL: I’m Dana Hill and my guest from the University of Florida College of Veterinary Medicine is Dr. Chris Martyniuk.
DANA HILL: And we’re talking about keeping horses and cows safe from poisonous plants.
DANA HILL: When we left off, Dr. Martyniuk, we had begun talking about some of the organs and systems in the body that can be adversely affected by some of these toxic plants.
DANA HILL: And we had mentioned some damage to liver and I wonder if we can talk some now about how the blood might be affected.
DANA HILL: Because the blood, of course, is something that transfers these chemicals probably throughout the body and many of the organ systems, you mentioned that that is how some of these toxins can reach the liver, which is designed to filter them out.
DANA HILL: But is there?
DANA HILL: Earlier you mentioned a story about the red maple being dangerous for horses.
DANA HILL: What else can be bad for the blood?
CHRIS MARTYNIUK: Yeah, so in addition to the red maple, white sweet clover is another one here that we have in Florida that livestock can get into.
CHRIS MARTYNIUK: White sweet clover has a very interesting story.
CHRIS MARTYNIUK: So back in the 30s, it was noted that many livestock, specifically cows, were succumbing to a bleeding disease, so they would hemorrhage and bleed out.
CHRIS MARTYNIUK: And this was during the Great Depression.
CHRIS MARTYNIUK: So losing a cow or two was a very, very big deal for many, and that really accounted for their livelihood.
CHRIS MARTYNIUK: And researchers at the University of Wisconsin basically isolated a compound that was causing the bleeding disease.
CHRIS MARTYNIUK: And this was produced really from moldy clover, white sweet clover.
CHRIS MARTYNIUK: And this compound, dicumarol, which was isolated, actually became a medicine that we’re all familiar with, Warfarin, which is used as a blood thinner and is one of the most popular medicines.
CHRIS MARTYNIUK: The World Health Organization has it labeled as a required or essential medication.
CHRIS MARTYNIUK: So we know it as a blood thinner.
CHRIS MARTYNIUK: And the reason why it’s called warfarin was because the compound was isolated in Wisconsin.
CHRIS MARTYNIUK: So it was the Wisconsin-associated research foundation that funded the research at the university.
CHRIS MARTYNIUK: So warf or warfarin, and same mechanism.
CHRIS MARTYNIUK: So what it does is it basically like the plant itself will stop clotting of the blood and the animal will bleed out.
DANA HILL: Well, that’s terrible, of course, but this is.
DANA HILL: This is something that, you know, well, if you don’t get injured, maybe it doesn’t.
DANA HILL: It’s not a problem.
DANA HILL: But these animals that might, you know, have.
DANA HILL: Look out in the pasture, you.
DANA HILL: You get little cuts and scrapes, right?
DANA HILL: Maybe you stick your head through the barbed wire and you get a little cut on the neck or something like that.
DANA HILL: If you’re sticking your head through in order to eat a bunch of white sweet clover, how quickly does this act?
CHRIS MARTYNIUK: It could happen within a few days.
CHRIS MARTYNIUK: And so what happens is that the compound basically inhibits an enzyme that’s very important for recycling of clotting factors.
CHRIS MARTYNIUK: And first couple days, you still have clotting factors in your blood and they’re able to do their job.
DANA HILL: They.
CHRIS MARTYNIUK: But over time, those become depleted and they can’t be replenished.
CHRIS MARTYNIUK: And then you end up not being able to clot and you bleed out.
CHRIS MARTYNIUK: And really the enzyme is Vitamin K, epoxide reductase.
CHRIS MARTYNIUK: But vitamin K is the key word because the gold standard treatment for this disease, which there are few for poisonous plants, is that you just administer back Vitamin K and that will again initiate the clotting.
CHRIS MARTYNIUK: So that is the treatment for this toxicosis.
DANA HILL: Okay, but you gotta stop eating the clover first.
CHRIS MARTYNIUK: Yes.
CHRIS MARTYNIUK: Presumably you have stopped eating the clover by this point.
DANA HILL: Okay, well, I mean, so that is.
DANA HILL: That’s good to know.
DANA HILL: But it’s still something that.
DANA HILL: Do you see this?
DANA HILL: I mean, is this something that veterinarians are called in to treat?
CHRIS MARTYNIUK: I think it’s observed once in a while, probably more so out in the West.
CHRIS MARTYNIUK: But we know a lot about it and we’re very familiar with this toxicosis.
CHRIS MARTYNIUK: And so I think the word is out to look for that.
CHRIS MARTYNIUK: But it does happen.
CHRIS MARTYNIUK: And another interesting sidebar is that this compound, warfarin, we’ve actually use it as a rodenticide, which is a small animal toxicosis.
CHRIS MARTYNIUK: If animals ingest these rodenticides, they can bleed out.
CHRIS MARTYNIUK: They’re meant to control rat populations, and they can, again, promote hemorrhage.
CHRIS MARTYNIUK: And that’s how these rodents succumb to the toxicosis.
CHRIS MARTYNIUK: So very famous medicine, very famous rodenticide.
CHRIS MARTYNIUK: All related to a poisonous plants.
DANA HILL: Wow.
DANA HILL: But also horrifying.
DANA HILL: All right, so let’s talk about breathing.
DANA HILL: We can all kind of understand how important that is.
DANA HILL: And yet there are toxins in plants that can hinder breathing, make it difficult.
DANA HILL: And is this related, of course, to oxygenation?
DANA HILL: Right.
DANA HILL: I mean, if it’s one thing if your blood can’t hold the oxygen in it, it’s another thing if your lungs are not working correctly.
CHRIS MARTYNIUK: Correct.
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: And there’s different kind of mechanisms that all lead up to impaired respiration.
CHRIS MARTYNIUK: And you did mention the impaired lung.
CHRIS MARTYNIUK: Again, I gave you that example of 3-methylindole with the lush green pastures.
CHRIS MARTYNIUK: Sweet potatoes, too.
CHRIS MARTYNIUK: If they are contaminated with a fungus, they can also induce kind of pneumonia in livestock.
CHRIS MARTYNIUK: So don’t eat sweet potatoes that are very green.
CHRIS MARTYNIUK: They have higher levels of this toxin, but livestock don’t know the difference.
CHRIS MARTYNIUK: And so if they’re eating a lot of moldy potatoes, those issues can occur.
CHRIS MARTYNIUK: In terms of the blood and carrying oxygen.
CHRIS MARTYNIUK: There is something called nitrogen fixation or nitrogen fixators.
CHRIS MARTYNIUK: These are plants that produce high levels of nitrogen.
CHRIS MARTYNIUK: So, for example, Johnson grass, pigweed.
CHRIS MARTYNIUK: There’s many, many different types of plants that do this.
CHRIS MARTYNIUK: When plants get stressed, they produce nitrogens.
CHRIS MARTYNIUK: And if an animal ingests those plants, the nitrogen hemoglobins actually change your hemoglobin, and it makes your hemoglobin less likely to carry oxygen in your blood.
CHRIS MARTYNIUK: So that condition is called methemoglobinemia, and it turns your blood brown.
DANA HILL: Yikes.
DANA HILL: Okay, can you describe what hemoglobin is.
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: So hemoglobin is a protein that’s in your blood, in red blood cells that is responsible for carrying oxygen to your tissues.
CHRIS MARTYNIUK: So that’s how the red blood cells carry your oxygen.
CHRIS MARTYNIUK: And if hemoglobin in the red blood cells are non-functional, then you’re not able to bind oxygen and carry it throughout your circulatory system.
DANA HILL: And it seems like that that would be really stressful.
DANA HILL: I mean, do the plants.
DANA HILL: I’m sorry, do the animals who are experiencing this condition exhibit clinical signs that would be noticeable?
CHRIS MARTYNIUK: They do if they ingest high levels.
CHRIS MARTYNIUK: And so even 30, 40% methemoglobinemia, where your hemoglobin has changed to this other form, the animals can exhibit cyanosis, which is blue coloring.
CHRIS MARTYNIUK: So basically you can’t get oxygen to your tissues, so you start turning blue.
CHRIS MARTYNIUK: So livestock can have blue tongues, blue ears, they can have impaired respiration.
CHRIS MARTYNIUK: They’re trying to get more oxygen because they don’t have enough.
CHRIS MARTYNIUK: So there might be rapid breathing, shallow breathing, panting, they might be anxious, and eventually they’ll succumb to toxicosis.
DANA HILL: Is it reversible?
CHRIS MARTYNIUK: It is reversible.
CHRIS MARTYNIUK: There is a gold standard treatment, methylene blue, basically, that’s just administered to the animals.
CHRIS MARTYNIUK: And that compound actually converts the methemoglobinemia back to hemoglobin.
[00:37:14] CHRIS MARTYNIUK: So you can transform it back to hemoglobin, which then again carries the oxygen safely to your tissues.
CHRIS MARTYNIUK: So that is the gold standard treatment for this.
DANA HILL: Is that a quick process?
DANA HILL: Would it happen fast enough for the animal to feel rapid relief?
CHRIS MARTYNIUK: Yeah, within hours, you know, so you might have to give repeated doses of the compound, but maybe over an eight hour period, the animal will start to exhibit signs of being well.
CHRIS MARTYNIUK: So yeah, again, it all depends on how many of these, how much of this plant has been ingested and how high the nitrogens are in the blood.
DANA HILL: Yeah.
DANA HILL: And what plants, again, do you say can cause that?
CHRIS MARTYNIUK: So pigweed is a nitrogen fixator.
CHRIS MARTYNIUK: Johnson’s grass as well.
CHRIS MARTYNIUK: Lamb’s quarter.
CHRIS MARTYNIUK: That’s a type of plant that grows on the forest floor.
CHRIS MARTYNIUK: Many, many plants.
CHRIS MARTYNIUK: And really a lot of plants do this as a defense mechanism against drought, against stress, so against fertilizers, against cold snap.
CHRIS MARTYNIUK: So farmers need to be aware that after a cold snap, you using high amounts of fertilizer can stress plants out to a point where they’re making high amounts of nitrogen.
DANA HILL: The kidneys are one of our body’s most important organs and we got two of them.
DANA HILL: I imagine that large animals do as well.
DANA HILL: What kinds of toxins can adversely affect the kidneys?
CHRIS MARTYNIUK: Yeah, so red maple, again, can affect the kidneys.
CHRIS MARTYNIUK: You could end up with blood in the kidney.
CHRIS MARTYNIUK: That, again, is horse specific toxicosis.
CHRIS MARTYNIUK: Bracken fern can also affect that organ as well.
CHRIS MARTYNIUK: So that’s another plant that’s ubiquitous in Florida.
CHRIS MARTYNIUK: Affects the liver, but can also impact the kidneys.
CHRIS MARTYNIUK: Oak is another big one.
CHRIS MARTYNIUK: So with cows, if they’re around oak trees and they like the taste of acorns and they’re going to ingest a lot of acorns, what they have is a compound called tannins in it.
CHRIS MARTYNIUK: The tannins are what is also found in red wine, and it dries out the oral cavity, can cause ulcers in the mouth.
CHRIS MARTYNIUK: Ulcerations in the gastrointestinal system impact the kidney negatively and can lead to death eventually.
DANA HILL: All kinds of oaks or just some kinds?
CHRIS MARTYNIUK: All oaks can potentially be toxic.
CHRIS MARTYNIUK: Some species produce higher levels of tannins than other.
CHRIS MARTYNIUK: The big issue is the acorns, and you don’t want livestock exclusively feeding on acorns.
CHRIS MARTYNIUK: So during certain times of the year, there’s lots of acorns, and they will have a propensity to eat a lot of those nuts on the floor.
DANA HILL: I mean, these are a favorite of squirrels.
DANA HILL: How are squirrels not just dropping dead from.
DANA HILL: From all of this?
CHRIS MARTYNIUK: Yeah, I don’t think they eat to the same extent as the livestock.
CHRIS MARTYNIUK: So the cows do have to ingest high, high levels of it.
CHRIS MARTYNIUK: But it has been reported to be a $10 million issue out west for, you know, loss of livestock and a problem.
CHRIS MARTYNIUK: So it can be significant.
DANA HILL: Wow.
DANA HILL: Okay.
DANA HILL: What about elephant ears?
DANA HILL: Elephant ears are a plant that I think many of us are fond of because they’re really attractive in the landscape.
CHRIS MARTYNIUK: Yes.
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: Elephant ears can also affect the kidney.
CHRIS MARTYNIUK: Very interesting.
CHRIS MARTYNIUK: Those plants, as well as others like dieffenbachia or many of your listeners might know of golden pothos, which is in the house at times.
CHRIS MARTYNIUK: These plants contain oxalic acids, which can physically damage the kidney.
CHRIS MARTYNIUK: So basically, the kidney ends up with crystals in it, and that causes structural damage and also causes issues with calcium in the blood.
DANA HILL: We’ve got to take one more break.
DANA HILL: I want to tell you all that this is Animal Airways Live here on WUFT-FM.
DANA HILL: We will be back with more right after this.
DANA HILL: Stay tuned.
DANA HILL: Welcome back to Animal Airwaves Live.
DANA HILL: I’m Dana Hill.
DANA HILL: My guest from the University of Florida College of Veterinary Medicine is Dr. Chris Martyniuk, and we’re talking about plants that can be poisonous or toxic to animals, specifically livestock, horses and cattle.
DANA HILL: Dr. Martyniuk, what about a plant, a tree that is common, especially here in Gainesville?
DANA HILL: There’s, in fact, the whole kind of.
DANA HILL: There’s a wood around here called Loblolly woods.
DANA HILL: Are loblollies potentially dangerous to any livestock?
CHRIS MARTYNIUK: They can be, yes.
CHRIS MARTYNIUK: So they produce a compound which actually causes abortions in wildlife.
CHRIS MARTYNIUK: So pregnant animals feeding on these trees, usually this happens in the winter when they’re available.
CHRIS MARTYNIUK: Maybe not so much here in Florida, of course, but throughout the rest of the US they can cause reproductive issues and abortions.
DANA HILL: And that is something that.
DANA HILL: Obviously it happens.
DANA HILL: There’s no way to fix it.
DANA HILL: But, I mean, what part of the plant is the problem?
DANA HILL: I mean, I can’t imagine that the animals would eat the needles.
DANA HILL: Is it the cones?
CHRIS MARTYNIUK: It is the needles, actually, that do contain isocupressic acid as well as other parts of the.
CHRIS MARTYNIUK: Of the tree.
CHRIS MARTYNIUK: But the compound can be found in those needles.
DANA HILL: So these are lying on the ground, and then the animals that are grazing, are they grazing specifically for these needles, or are they trying to get the grass that’s underneath and they ingest the needles?
CHRIS MARTYNIUK: Yeah, I think both scenarios are possible where they’re actively seeking more food through the needles or accidentally ingesting them by grazing with the wildlife.
CHRIS MARTYNIUK: It’s been more reported in wildlife in the cold winter, not a lot of food around.
CHRIS MARTYNIUK: These trees are sometimes the only thing available.
CHRIS MARTYNIUK: So they’ll eat those trees, those needles, and then experience that toxicosis.
DANA HILL: Wow.
DANA HILL: Okay.
DANA HILL: Well, that’s pretty.
DANA HILL: That’s pretty terrible.
DANA HILL: We mentioned earlier oleander as being a dangerous plant, and it’s an ornamental plant, but.
DANA HILL: But it’s probably something that is not unheard of for livestock to get a hold of.
DANA HILL: What can happen?
CHRIS MARTYNIUK: Yeah.
CHRIS MARTYNIUK: So there have been reports of oleander accidentally being mixed into the food for zoo animals.
CHRIS MARTYNIUK: And the danger with oleander, even though it’s a very beautiful Mediterranean plant transplanted here to Florida, is that it can cause cardiotoxicity or damage to the heart.
DANA HILL: Okay.
DANA HILL: And with something like that, is it reversible?
CHRIS MARTYNIUK: It’s really quick.
CHRIS MARTYNIUK: So there’s really not much you can do.
CHRIS MARTYNIUK: You can treat some of those clinical signs and biochemical changes that occur.
CHRIS MARTYNIUK: You could use different pharmaceuticals to maybe slow the heart or increase the heart, depending on, you know, what the manifestation of the toxicosis is.
CHRIS MARTYNIUK: But basically, it causes changes in heart rate and blood pressure.
CHRIS MARTYNIUK: And what a veterinarian would do would be to try to mitigate or reverse that with pharmaceuticals and with supportive care.
DANA HILL: Yeah.
DANA HILL: What else can affect the heart?
CHRIS MARTYNIUK: Other toxins that can affect the heart would include things like butterfly plants, milkweeds.
CHRIS MARTYNIUK: So they can also impact the heart.
CHRIS MARTYNIUK: Small animals typically don’t ingest a lot of milkweeds, but they grow wild, and livestock can ingest those types of plants.
CHRIS MARTYNIUK: And they have a very similar kind of mechanism of action.
CHRIS MARTYNIUK: They affect heart rate.
CHRIS MARTYNIUK: They can lead to changes in the.
CHRIS MARTYNIUK: The strength of the heart in terms of how it’s beating.
CHRIS MARTYNIUK: And that can, of course, lead to more sinister issues down the road.
DANA HILL: I think what’s fascinating about this scenario is that milkweed, which benefits from animals in the form of butterflies and welcomes butterfly visitors with its flowers, Butterflies help this plant reproduce.
DANA HILL: It is dangerous to other kinds of animals.
CHRIS MARTYNIUK: Exactly.
CHRIS MARTYNIUK: And that’s why the butterflies feed on those plants.
CHRIS MARTYNIUK: They actually take up the poison.
CHRIS MARTYNIUK: And animals know not to eat the butterflies because they’re carrying milkweed poison.
DANA HILL: Golly wow.
DANA HILL: Nature is amazing.
DANA HILL: Finally, something that we have just a bit of time left, but we ought to talk about are toxins that can affect the neurological system, including the brain.
DANA HILL: What can cause problems in this area, which, I would have to think again, would be pretty bad.
DANA HILL: The brain’s important.
CHRIS MARTYNIUK: Yes.
CHRIS MARTYNIUK: And a lot of these toxins do affect the brain.
CHRIS MARTYNIUK: I would say the central nervous system is one of the most widely targeted tissues in terms of plant toxins.
CHRIS MARTYNIUK: So many different plants can do this.
CHRIS MARTYNIUK: Some examples would be poison hemlock and water hemlock.
CHRIS MARTYNIUK: Those plants are considered to be two of the most dangerous plants we have here in North America.
DANA HILL: But famously poisonous.
DANA HILL: Hemlock is famously poisonous.
CHRIS MARTYNIUK: Yeah, famously poisonous.
CHRIS MARTYNIUK: And even Socrates back in the day, he chose to drink poison hemlock as a way of being punished for his views on democracy.
CHRIS MARTYNIUK: And it caused him to writhe in pain, hallucinate, convulse, very, very dramatic way to die.
CHRIS MARTYNIUK: But that can happen to animals, too, that eat it.
DANA HILL: Wow.
DANA HILL: Gosh, we’re just almost right up against the clock.
DANA HILL: Creeping indigo is something that can affect or horses in Florida.
CHRIS MARTYNIUK: Absolutely.
CHRIS MARTYNIUK: And it’s one toxin that anyone in Florida should be highly aware of.
CHRIS MARTYNIUK: It affects horses, causes liver damage and damage to the brain, too.
CHRIS MARTYNIUK: So get familiar with that plant if you have a pasture, and keep your horses away from it.
DANA HILL: Well, Dr. Martyniuk, I feel like the time passed very quickly here, and I feel like we could have gone even longer.
DANA HILL: But suffice it to say, there are plants in our environment that can adversely affect livestock.
DANA HILL: And what a person can do, of course, is just try to become aware.
DANA HILL: I mean, are there resources for folks who have animals to investigate this and keep safer pastures.
CHRIS MARTYNIUK: Yeah, absolutely.
CHRIS MARTYNIUK: There’s many different resources here at the University of Florida.
CHRIS MARTYNIUK: IFAS has a very, very good website that kind of provides an overview of all these toxic plants.
CHRIS MARTYNIUK: I mean, look at as many pictures as possible online to really get to know which plants might be out there in your pasture.
DANA HILL: Great advice.
DANA HILL: All right.
DANA HILL: Thank you so much, Dr. Martyniuk.
DANA HILL: Chris Martyniuk is a veterinarian at the University of Florida College of Veterinary Medicine, where I also want to thank Sarah Carey for her help with the program.
DANA HILL: And I want to thank all of you for listening.
DANA HILL: And I hope you’ll join me next time for another episode of Animal Airwaves Live.
DANA HILL: Bye.