New findings in the Spring Mycotoxin Report highlight a growing threat to dairy herd health and profitability. In this episode of Ruminate This, Scott Zehr and Dr. Larry Roth break down the newly released Spring Mycotoxin Report and what over 800 feed samples reveal about mycotoxins growing risk, especially from fumonisin. We discuss how this increasingly common mycotoxin is affecting gut health, liver function, and immune response in dairy cows, and what you can do to protect performance and profitability.
🎯 Tune in to learn:
How fumonisin is quietly undermining cow health in corn silage and TMR
– What to look for in feed analysis and why by-products may increase risk
– The best ways to respond
– What the data tells us to expect this fall (and how to prepare)
– Don’t wait until problems show up in the bulk tank, stay ahead of mycotoxins with practical strategies that protect your herd and your ROI.
🎧 Listen now to set your herd up for lifelong success!
Scott Zehr
Hey, welcome everybody to another edition of Ruminate This with Agrarian Solutions. I’m your host, Scott Zehr. And today I’m, I’m happy to be bringing in Dr. Larry Roth as we discuss our spring mycotoxin report, a bit of a PSA for the listeners out there. So, we’re gonna dive into a couple things with the mycotoxin report.
One, we’ll talk about the number of samples that we have looked at here in the last few months, as well as the levels we’re seeing of the different types of mycotoxins across the country. But also, Larry, I’m gonna ask you to dive into why we think we’re seeing a rise. I shouldn’t say why we think we’re seeing. Why we’re seeing a rise in fumonisin in our sample database. So Dr. Roth, if you would just kind of give your overall synopsis from a 10,000 foot view of this mycotoxin report this time.
Dr. Larry Roth
You bet. All right. Appreciate it being on here with you today, Scott. Well, DON continues to be an issue for what I’m gonna call the northeastern third of the country. From Wisconsin, Illinois, and then East and up into Maine. Zearalenone continues to be kind of hit and miss, but kind of a similar type of problem.
But probably the biggest thing that came up this year was fumonisin. We’re getting more samples out of Virginia, North Carolina, and Tennessee, and those were areas that we’re experiencing some drought last year along with Pennsylvania, and we’re seeing elevated levels of fumonisin.
You know, Scott, we’ve put such a emphasis on DON in the past and cool weather mycotoxin and yeah, it’s been a, a challenge. But I really think we gotta go back to the basics. Why do we get mycotoxins? The plant is stressed, too wet, too cold, too dry. And this year we ran into parts of the country that it was too hot and too dry.
And ironically, many of these areas showed elevated levels of DON. I call that kind of a cool weather mycotoxin, and then fumonisin as well. Maybe a little bit more of a hot weather mycotoxin. Not quite like aflatoxin, but kind of getting that way, so. We continue the trend of elevated DON, zearalenone, and now fumonisin is trying to get in on, on the game, Scott.
Scott Zehr
So that’s one that we haven’t talked a ton about. You and I did a podcast earlier in the middle of last year going through the big five. But refresh our memories a little bit on fumonisin and some of the issues that can arise from that.
Dr. Larry Roth
You bet. Well, fumonisin follows as one of those mycotoxins that will destroy gut integrity. And again, we’ve talked about this ad nauseum. We look at the digestive tract lining as the castle wall to keep the bad stuff in the digestive tract. So fumonisin will degrade intestinal integrity and then attack the liver. And the liver, the body’s biochemical factory, we have to protect it. And fumonisin going to lessen the ability of that factory to produce what we need: nutrients.
Scott Zehr
And then our fun fact on fumonisin, also used in human medicine, correct, Larry?
Dr. Larry Roth
Yeah. Sometimes they’ll use it in fumonisin and some cancer treatments and, and things such as that. But for our discussion today, we think about the transition cow and all that the liver has to do. And now not only does the liver have to do all of the processing of these nutrients, but the liver’s gotta deal with fumonisin that lessens its capabilities of producing nutrients as well as cleaning up other metabolites in the body.
Scott Zehr
And folks, if you’re listening and you haven’t subscribed to our RISE e-newsletter you can send us a email [email protected]. We’ll get you on that email list so you can get the newsletter, which we would have the mycotoxin report in it. And also, we will provide the mycotoxin report in a link in the show notes of this episode.
So Dr. Roth, we’ve seen some wild ranges of zearalenone this year. I’ve seen samples that come back with maybe 40 parts per billion, on the low end. And I’ve seen samples come back with 2,500 parts per billion, 4,000 parts per billion on the high end. Where is that average kind of falling across what you call the northeast third of the United States?
Dr. Larry Roth
Okay. Well, I would say we’re gonna be in that medium risk level. You know, somewhere in the a hundred to 300 parts per billion per zearalenone. And while that’s a concern on its own, it’s the cumulative impact of all of these mycotoxins coming together. For example take the state of Pennsylvania. When I look at TMR values, it’s in the high risk, it’s medium risk for zearalenone, it’s a lower risk for T-2, and is a high risk for fumanicin. So two highs, a medium and a low. Wow. That’s a lot for that cow to deal with.
And I, and I think that Scott, so often we talk about mycotoxins and for this specific mycotoxin, what levels do we need to be concerned about? Yeah, it’s good to look at it that way. But really we need to be concerned about what is the cumulative mycotoxin load that the cow has to deal with. And again, we look at dietary values. We’ve talked about this before.
If we’re not providing mycotoxin protection to the cow during the dry period, she could actually be storing up mycotoxins in her fat tissue. She freshens, she’s got such a high energy demand that she’s gotta melt some of the fat off of her back. Well, if that fat was containing mycotoxins, wow, we’ve just increased what she’s got to deal with.
So we, we really need to be thinking about cumulative dietary mycotoxin levels. And then also, and I don’t really have a term for this, should we say the metabolizable levels? What is it that is now becoming available from a mycotoxin that she’s having to take some of the fat off of her back.
Scott Zehr
That’s a great point. And you, you and I have actually seen, a case study, I’ll call it, where we theorized that we had stored mycotoxins in the dry cows causing subclinical ketosis and even clinical ketosis. And you know, that particular case study, once the cows freshened in, that had been protected with DTX, the ketosis problems magically went away.
Dr. Larry Roth
Yeah.
Scott Zehr
So there is, there is something to consider there folks.
Dr. Larry Roth
Yeah. When we talk about ketosis, it’s kind of a shortage of glucose, shortage of energy, but principally glucose. And if the cows having to deal with mycotoxins, the immune system needs glucose as its energy currency to go out and do battle.
Well that’s diverted glucose away from other things that the cow needs to use it for: metabolism, making milk. No glucose, no lactose, no milk. That simple. And then also we need the glucose for the rapidly developing egg cell that’s inside the cow.
Scott Zehr
Right.
Dr. Larry Roth
So there, there’s so many things that the cow’s having to deal with at one time. And hence if it was just one of these mycotoxins, the cow could probably handle it better. But it’s when we got so many of them coming together at the most inopportune time.
Scott Zehr
So you made reference to the cocktail, the four-way toxin cocktail in Pennsylvania there on TMRs. And we, we do get a lot of TMR samples, but how many samples were in that database?
Dr. Larry Roth
Okay, great question. 506 TMR samples from across the country. 323 corn silage samples. And let me back up. These are samples that we collected between October 1st, of 2024 and March 31st, of 2025.
Scott Zehr
Yep. And so…
Dr. Larry Roth
So six month time period.
Scott Zehr
So 2024 corn silage. I mean, we’re seeing some of that data now as, as guys have gotten into the bunks, you know, probably back in December. January. Where is, is corn silage the, the predominant contributor to those high TMR levels? I mean, obviously we’re feeding a lot of corn silage. It can contribute, but where are the toxins coming from? Is it the corn silage? Is it the dry corn? Where else?
Dr. Larry Roth
Okay, great question. Corn silage is going to be the majority of the mycotoxins that the cow’s having to deal with. There could also be mycotoxins coming from the corn grain, be it dry corn or high moisture corn or, or snaplage. So we have that coming in as well.
And then sometimes we have some of our cotton products that can bring in issues. But what’s interesting is that Scott, in all of these samples that we analyzed, and that was what, over 800, we did not detect any aflatoxin.
Scott Zehr
It’s been a long time. I mean, have I seen maybe one sample in the last five years?
Dr. Larry Roth
Yeah. And I think…
Scott Zehr
Maybe two.
Dr. Larry Roth
…that that probably came from a TMR that was feeding a lot of cotton products.
Scott Zehr
Yeah, yeah.
Dr. Larry Roth
Yeah, go ahead.
Scott Zehr
Just going back to why I think our story here at Agrarian is really neat is that the products on the marketplace that we have, you know, continued to use over the last 25-30 years to combat this broad array of mycotoxins were developed specifically for a toxin that we don’t really find anymore. Larry?
Dr. Larry Roth
Yeah, early.
Scott Zehr
So we covered the corn silage. Certainly we wanna be testing if you’re, you know, feeding your homegrown grain corn. Like Larry said…
Dr. Larry Roth
Yep.
Scott Zehr
…dry corn or high moisture corn. Sample. Sample. Sample. So, Larry, why is it so important, number one, to sample the ingredients? Number two, to sample the TMR? And then number three, what’s the importance of us doing this mycotoxin report for folks?
Dr. Larry Roth
You bet. So we need to know what challenges the cow’s facing. We can go out and we can walk the cows. We get an estimate on what stocking rate might be. We know what’s happening temperature wise for heat stress that the cow has to deal with. But what about mycotoxin challenges?
Well, there’s only one way we’re gonna know that, and that’s the testing the feed. We can’t really look at the feed and tell if there’s mycotoxins there or not, so we gotta go test it. And then we look at the different sources. Well, a lot of these diets today are very heavy on the corn silage side. And you got all of this great biomass out there in the corn field that is just an ideal environment for molds to grow and start to produce their mycotoxins.
Again, think of the biomass differences in a cornfield today versus one, I’m gonna say even 25 years ago. Higher planting rates. All of this is going on. So we think about what kind of microenvironment do we create in the corn field that could be conducive to making mycotoxins. And then we feed more byproducts today than I think in the past.
Yeah. Anytime we’re feeding byproducts, we’re concentrating the mycotoxin that came with that base feed. I hope I don’t step on any toes here, Scott, but if a corn producer’s got a semi corn he needs to get rid of and he knows there might be some mycotoxins there, he’s not going to take it to a plant that’s making human food.
He is probably not gonna take it to a feed mill that he knows is testing for mycotoxins. He’s probably gonna take it to that ethanol plant. And then that mycotoxin gets increased by a factor of three. So, yes, it’s important to test corn silage, but corn silage is not the only source of mycotoxins.
What’s our corn source? What’s the level of our byproducts that we bring in? And then also again, think about cotton products that can bring in not just aflatoxin, but some of these other mycotoxins, most notably fumonisin.
Scott Zehr
Yeah. Larry when will our next mycotoxin report come out?
Dr. Larry Roth
Next one will come out in October.
Scott Zehr
October. Okay. I just wanted to make sure we gave the listeners a heads up on when that’ll be. Well, Larry, I guess any final parting words, takeaways from the mycotoxin report that you would have?
Dr. Larry Roth
I think the big thing that we’re starting to see in the country is multiple mycotoxins showing up at the same time. It used to be, we would just be concerned about this one or that one. Now there just seems to be multiple mycotoxins building up. And be concerned about fumonisin, especially if you’re in the Mid-Atlantic area from Tennessee, Kentucky, Virginia, Maryland, and Pennsylvania, fumonisin is an issue.
Scott Zehr
Yes, it is.
Dr. Larry Roth
And Scott, maybe we should set the stage for harvest coming. I mean, there aren’t many parts of the country that have been planting corn. But we should start thinking about corn silage harvest and sampling the fields going into storage, so that we know…
Scott Zehr
Absolutely.
Dr. Larry Roth
… what we’ve got from a nutrient inventory standpoint, but also a mycotoxin risk. So, let’s take this as an opportunity to encourage folks to start thinking about corn silage harvest and sampling fresh corn silage for mycotoxins.
Scott Zehr
Well, Dr. Roth, you know, I, I almost forgot to ask you the million dollar question on this podcast. I’m gonna blame it up to a broken foot that has my brain a little crazy today. But do we provide protection from fumonisin? From the negative effects of fumonisin?
Dr. Larry Roth
Absolutely, absolutely. Again, it comes to the DTX technology, enhancing gut integrity, cleaning up the intestinal cells, and I realize the majority of the listeners to this call are working on the ruminant side. But there was some neat research early on in the Agrarian history done with chicks, done with broiler chicks, showing that supplementing the DTX technology went a tremendous ways for protecting the very rapidly growing broiler chicks. Again, not calves, not cows. But, we know that the DTX technology works at the gut level to help protect against fumonisin.
Scott Zehr
Exactly. All right. Well, Dr. Roth, I want to thank you once again for jumping back in with us here and Ruminate This and I look forward to talking to you again soon.
Dr. Larry Roth
Alright, thank you Scott. Appreciate it.
Scott Zehr
Thank you.
