61: Mycotoxins & Subtle Stress: Why Cows Look Fine but Performance Drifts

What do you do when the cows look perfectly fine but performance keeps drifting? In this episode of Ruminate This, Scott Zehr breaks down the quiet, hard-to-detect issue plaguing many dairy herds: subtle biological stress, especially from low-level mycotoxins that rarely show up on a single feed test but can dramatically impact herd performance.

Scott explains how cows can look visually healthy while quietly battling stress that affects reproduction, rumination, immune function, intakes, components, manure consistency, and overall milk production.

In this episode, you’ll learn:

• Why cows “whisper” their symptoms instead of crashing.
• How low/medium DON, Zearalenone, T-2, and Fumonisin levels still cause major damage.
• Why mycotoxin tests often mislead (uneven distribution + sample variability).
• The real signs of toxin pressure: weak heats, cysts, SCC drift, soft milk, inconsistent manure, fluctuating intakes.
• Why patterns matter more than single data points.
• How to use Agrarian’s DTX Decision Chart to identify immune suppression.
• A real case where cows looked totally fine until toxin correction turned the herd around.
• Exactly what to review in your last 90 days of herd data to spot hidden stress before it becomes costly.

If your cows look “fine” but your numbers don’t, this episode will give you the clarity you’ve been searching for.

Resources:

• Mycotoxin Decision Chart
• Mycotoxin Guide

🎧 Listen now on Apple Podcasts, Spotify or your favorite podcast platform 

To learn more on this topic, email podcast@agrsol.com.

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Transcript

0:01

Hello everyone, welcome to Ruminate This with Agrarian Solutions. Join us as we explore ruminant nutrition and the impact of mycotoxins. Here we challenge your curiosity and explore new industry insights and research to optimize your herd's health and performance. Hey everyone, welcome back to Ruminate This. I'm your host, Scott Zare, and today we're going to talk about something that every single producer listening has dealt with. Whether you realize it or not, you've definitely dealt with it. And it's that moment that you, as a producer, walk through your barn, you look at your cows and say, they look fine. So why does something feel off? Maybe milk is a little bit soft. Maybe Repro is not quite where you think it should be. Maybe somatic cell is drifting a little bit. Manures just don't seem quite all that consistent. Maybe cows are eating, but not really driving at the bunk the way you would expect, for the way you've seen in the past. But as much as you talk to your team of people, it just nobody can put their finger on it. So this episode exists for one reason, and that's to hopefully give you some clarity. Clarity on why the cows can look perfectly fine, but still be struggling. Clarity on why performance drifts. Clarity on why mycotoxin test results might look low, but the cows say otherwise. The cows don't lie, don't always know what they're saying. Clarity on what subtle stress is doing to your cow's immune system, your repro, your milk tank, and most importantly, your sanity. So my purpose today is really simple: it's to give you a compass, something that you can trust when the numbers don't add up, when the results don't match a test, and your gut is telling you something's wrong. Welcome to the episode that producers have actually been asking for, even if they didn't know what to call it. So let's start with the uncomfortable truth. And if you've listened to this show long enough, I really don't try to hide from the truth. And the truth is your cows can look fine and still be under significant biological stress. It might not be enough to make them crash, it might not be enough to knock them off feed, it might not be a stress that's enough that your vet spots it in a heartbeat. It's the whispering kind of stress. And, you know, we talk about mycotoxin sampling a lot on this platform. We talk about, you know, at what levels should we be concerned? You've probably had conversations with your nutritionist about what levels we need to be concerned at. But what I want to kind of bring up today is that low test results on your toxin assay does not necessarily mean low mycotoxin risk. So why is that? There's a few things. Mycotoxins are not distributed uniformly across your fields, they are not distributed uniformly across your silage pile or your storage pile. You know, we have to keep in mind that we're pulling approximately a one-pound forage sample. And I think the takeaway from that is the sample you send in, those numbers are extremely accurate. But the variability that comes from mycotoxins not being distributed evenly, you could run into that same corn silage pile testing at one level today and potentially a different level in a week. This is why we are big proponents of regular monthly sampling to try to establish that baseline. And there are times when low-level sample analysis results still require a proactive response. We've been taught largely over the last 20 to 25 years, like, here's the sample results, we can trust the sample results, and then you know, the cows, we kind of talk second or we trust them second. If I've said it once, I've said it a thousand times. You know, the cows don't lie. That's why I love talking to cows. I'm not a cow whisperer, but the cows always tell the real story. And so I think as much as I agree with you can trust the numbers that are presented in an assay, what you can't trust is for that assay to speak for the cows. So if you think about this and you know, flip it around, what if the cows have been telling us the truth the whole time and the tests give us a false sense of security at times? What if the problem isn't that your cows won't show you the signs? But the signs that they do show are so subtle and chronic, and the fact that they're distributed across multiple systems in the form of maybe weaker silent heats, cystic cows, a little bit higher number of short cycle cows, reduced milk, or maybe just milk that we can't figure out why we can't make, if that makes sense, reduced milk fat. And you know, you might say, Well, Scott, I'm 100% Holstein cows and we're making seven pounds of components. I guess my question is, I know some farms that have made eight pounds and have consistently approached eight pounds. So maybe we don't feel like milk fats are reduced because we don't really know what our ceiling is. Inconsistent manure, elevated somatic cell, intakes that seem to fluctuate from week to week. What if they weren't all just random isolated events? And what if they're not all independent of each other? And I didn't just talk about eight different problems. What if they are actually one problem showing up in eight different ways? So the thing is, we don't have to have a singular high toxin smoking gun to cause these things. Medium contamination, low contamination, but with multiple mycotoxins present can actually be just as detrimental as having one toxin at a high level. And that's where I think we get this false sense of security sometimes that oh, the essay looks good because nothing was in red, nothing was in the high challenge area. If that challenges your way of thinking a little bit, I'm glad it does. And so let's dive into that. So before we get too far, we'll kind of bring this down a little bit. And if you're listening to this and thinking, Scott, this does sound kind of familiar, that's probably because it is. I mean, I have the opportunities to walk in barns almost on a weekly basis, and I see this, I really do. But I promise you, you're not doing anything wrong, and you're not missing the obvious. You're not failing as a producer, as a manager, as a nutritionist. In fact, probably most herds I've ever visited that are experiencing, I would call it a lower mycotoxin challenge, they don't crash. Where I got to the farm and I said, I said at verbatim, this might be the only time I've ever seen an acute mycotoxin issue. We had toxin levels so high that as soon as we started feeding the corn silage, everything went to crap. It was that big of a deal. I've never seen it since. I've never I'd never seen it before. Most herds that are experiencing low-level mycotoxin pressure, they don't crash. I would more describe it like they drift. And drift is really hard to diagnose when you're in the barn. It's the same idea of you know, when we talk about I can walk into a herd and say, you know, the dry cows look a little heavy, and the herdsman that sees the dry cows every day hears that and starts looking back and say, Oh, you know what, maybe they are a little bit, or maybe vice versa, right? Sometimes you're too close. Sometimes you're sitting in the boat that starts drifting, and you can't realize that you're drifting, but you are, you know. So recently I was on a farm, the transition cows moved from the heat out pile to the main pile, and within two weeks, we had a spike in mastitis, a few cows with what looked like black leg type swelling, rumination dropped, manure was inconsistent, had some cows going off feed, and milk just kind of softened, and you know, the cows overall looked fine, and it wasn't that we were convinced it was toxins, in fact, we we didn't really know, but it's it's time to take a test, and it's time to figure it out, and what'd we find out? Low toxin numbers. But when you look at our DTX decision chart, and I'll link that in the show notes. What we had was multiple mycotoxins present. We had transition challenges, we had repro challenges, we had production challenges, we had inconsistent manure, we had elevated cell count. And why I love the decision chart is because mycotoxin challenges are not cut and dried, it's never just like it. I would say it like this it's not like when you have four different mycotoxins present, they all affect the cow in the same way. So there's only one area that gets challenged. You know, and the cows were telling us a different story. The cows were telling us that there's an issue with the transition challenges, there's an issue with the repro challenges, production, manure, cell count, etc. You know, we added in DTX, and within a couple of weeks, the cows were eating more consistently. We saw somatic cell scores start to come down. By the time the first herd checks rolled around, there was more cows pregnant. You know, your palpation rate is the first number that we we see that starts to get better. And it really wasn't because we fixed toxins, but because we restored the immune system, the toxins were quietly suppressing. And and that's that's the big thing. When you let DTX take care of the toxins, the immune system doesn't have to. Let's talk about South on the Compass. It's okay to admit to ourselves that sometimes cows whisper and we miss it. I can remember a dairyman that I used to breed cows for, his name was Jim. Jim was probably the best cowman I've ever met in my entire life. Milked a hundred cows, knew every cow by personality and name. Even Jim would sometimes miss when a cow is off. Like it's human, you're human, it happens. We don't have the fortune of cows standing there with a megaphone telling us what's wrong, right? But I think that's what I love about what we do at agrarian, is that you each have access to the entire agrarian team to help listen to those cows. So we've named the problem, we've aligned the truth. So let's give some structure to this. So, how do we use that DTX decision chart? And again, it's it'll be in the show notes. You can you can check it out, grab the PDF of it, but look at the different categories, and you check every box that applies to what you're seeing. So maybe it's multiple mycotoxins present in the TMR, transition problems, repro drift, somatic cell or immune type problems, erratic intakes, reduced milk, and consistent manure. So the number of boxes you check is essential level. And if you're checking three or more boxes, your herd is not really necessarily dealing with a feed issue, you're probably dealing with an immune suppression issue, and there's a good chance it is coming from the mycotoxins. So, step two, we match those symptoms to known toxin patterns. So, from the mycotoxin guide, you'll see that if Don hits intake, so what I just talked about was the DTX decision chart. The other resource I'm gonna link in the show notes here is the mycotoxin guide. So, Don is gonna hit your intakes, probably gonna soften up on milk. Don could could inhibit your components, elevate your cell count. And we, you know, Don, I always tell guys, look for the inconsistent loose manure. That's Don. So Xeroanone, that's our estrogen mimicking mycotoxin. So that's our repro. That's probably more cystic cows or short-cycle cows, and twinning. Ironically enough, xorolinone can increase the percent of twins you have born. T2 is very hard on the gut linings on the gut wall. I think bloody manure and hemorrhaging. Oftentimes, I think hemorrhagic bowel is misdiagnosed as uh, I think T2 poisoning is misdiagnosed as hemorrhagic bowel syndrome, and then feminicin, it's gonna hit that gastrointestinal lining and help decrease milk yields. So, overlaying the symptoms, you know, what I would say is I think it's I can't reiterate this enough that the number you get back on your assay from Daryland Labs, that number is extremely accurate. But it doesn't necessarily mean it's representative of your entire corn pile or you know, tomorrow's TMR. You know, the guide kind of shows clearly that as we know, mycotoxins aren't distributed evenly in the field, in the storage pile, on the bunk. The sample we pulled today is a snapshot of what's in front of the cow today, not what's in front of her tomorrow or next week. And so, kind of all of that means that the the trend that you see from the boxes you check plus the samples is greater than the test all by itself, and the pattern you see with all the challenges that you seemingly can't put your finger on is greater than the parts that we have within that pattern, and your eyes. I mean, trust your eyes. I know it's data makes us feel good. We try to use data to confirm what our eyes are telling us, but sometimes I think sometimes I think we need to use our gut to confirm what our eyes are telling us, and then one of the things I always encourage people to do is let's look back 90 days. So let's ask ourselves, you know, what what subtle things have crept in in the last 90 days? Are multiple systems all drifting at once? Does Repro feel off? Not bad, not unacceptable, but off. And I would almost say I would define off as being I'm a firm believer that if you're doing a good job mitigating internal stressors and you're good at getting cows pregnant, your weekly percent pregnant on herd check day should be running 80%. I truly believe that. So maybe you're running 80% weekly, but one week a month or three times in the last two months, we only had 61% of the cows pregnant on vet check day. Are the cows eating? But yet some days they're not, you know. I just I would encourage you to go look at your way backs. Is there a pattern that that shows where maybe the week that we didn't have a good herd check was also the same week we had more waybacks? And then has Somatic Cell climbed slowly without a clear event that you can tie to it? And if the answer to those questions are yes, then we need to adjust. And the other thing about the DTX decision chart is we're able to evaluate these challenges and combine it with the toxin assay results, and we can adjust our rate of DTX based on the score of the boxes you checked. And so if you look at that DTX decision chart and you want to use it, find out what the score is that you came up with, where you fall in the chart, and take a picture of the DTX decision chart, email it to me, podcast at agrsol.com. And um, if you have any rumination data from your systems, or you want to send me your last three months of performance, like I'll be your second set of eyes, and not just me personally, like the team at Agrarian will be your second set of eyes. Because once you see that pattern, you can't unsee it. And I think this is one of those things that just speaks to the things that I've learned from the great people here at Agrarian, as far as you know, it's it's one thing to get all crazy and been out of shape or worry about high toxin, high toxin samples. That's when you know, that's when everybody in the room knows what the problem is and we all know how to fix it. But these are the things that actually make us lose sleep. It's when we see something and we can't quite put our finger on it. And I think the DTX decision chart does that. So I think once we kind of align that compass for you and send you that feedback, again, this is a serious offer. Podcast at agrsool.com and we'll take a look at it. But I think once you are able to kind of see things through that lens a little more clearly. Hey, and and I'll be honest with you, if we don't think it's a mycotoxin problem, we're gonna be the first ones to tell you. I promise you that. So, to wrap things up, you know, this episode really isn't about mycotoxins per se. I would say it's more about alignment, about maybe using a compass, uh something like the DTX decision chart to help us understand what the cows have been trying to tell you. Hopefully, I've been able to provide some clarity instead of noise around this topic and restore some confidence where there's been some uncertainty growing. Because it's it's about giving you direction when the symptoms don't seem to make sense. So, with that in mind, again, I'm gonna throw it out there again. Check in the show notes, the DTX decision chart, the mycotoxin guide, and podcast at agrsol.com. If you have questions on how to fill out the decision chart, shoot me an email, podcast at agrsol.com. I'll walk you through it, send the results back to us, we'll consult on it and get back to you and let you know. With that in mind, I will see everybody again in two weeks. Thanks for listening. Thank you for listening to ruminate this with agrarian solutions. Look for our next episode in two weeks.