Do forage inoculants really work, or are they just “insurance”?
Can they prevent or reduce mycotoxins in silage?
In this episode of Ruminate This, Agrarian Solutions’ Vice President of Nutrition, Dr. Larry Roth, explains the real role inoculants play in silage management. Tune in to learn how the right inoculant can help preserve dry matter and nutrient value, why it can’t remove mycotoxins already present at harvest, and the practical steps to get the most from your forage.
Think of your silage bunk as a pile of valuable nutrients, the more protein and energy you keep after fermentation, the less you’ll need to purchase. From harvest timing to packing, covering, and inoculant selection, understand how to best protect feed value, reduce losses, and keep your herd performing at its best.
🎧 Listen now to set your herd up for lifelong success!
Scott Zehr
Hey, welcome everybody to another episode of Ruminate This With Agrarian Solutions. I am once again your host, Scott Zehr, and today also joined with our Vice President of Nutrition, Dr. Larry Roth. I wanna make mention of something at the start of this, Larry. I was recently approached by a dairyman, and I think he was trying to call me out a little bit.
It was kind of a fun conversation actually. But he looked at me and he said, hey, and he’s got his phone ready and he is showing me an article from a popular dairy press magazine that I’m not gonna mention by name today. And he said, “I thought you told me that inoculates preservatives can’t help control mycotoxins.”
And I thought about what he said for a second and I said, “well, I think a lot of people think that we can reduce mycotoxins with a good inoculate preservative type product which is not necessarily true in that term. We can’t reduce what we bring in from the field.”
So I wanted to kind of bring you into this conversation today because surprisingly or not surprisingly, that still I think is thought by a lot of people that we can use a good inoculate or preservative and have less mycotoxins. You know, we’ve talked extensively on this platform in the past, like, Hey, what you bring in from the field is it’s there, it can only go up. So I guess we’re gonna ask you the big question right off the bat Larry. Does putting an inoculant on our corn silage, does it help in the realm of mycotoxins?
Dr. Larry Roth
Excellent question, Scott. Well, a good inoculant helps control or limit mycotoxins? Not necessarily. And I’m, I’m gonna say this from a couple of standpoints.
We can have a very excellent fermentation and when I define an excellent fermentation, a low pH with corn silage below a pH of four, very quickly within say, hmm 24 to 48 hours. And in some of those best preserved corn silages, we can get Roquefortine-C, we can get patulin. Patulin, we typically see that more with apple type crops, but we can see it sometimes with corn silage.
So I do not look at a well-preserved silage as necessarily lowering mycotoxin to come in from the field. I mean, really the whole purpose of silage fermentation is to preserve the nutrients that we have. Principally sugar and starch to a degree, amino acids, and that if we can drop the pH very quickly, we limit yeast growth.
If yeast start to grow, they create heat and we can create some heat damage protein. Acid detergent, style crude protein. So amino acids aren’t as absorbed. But the biggest thing we’re trying to do is drop the pH, stop the plant from breaking itself down so that we don’t lose sugar and starch, which also shows up in reduced dry matter.
And if we lose a lot of dry matter and it may not be unreasonable to lose 10 to 25% of the dry matter, which means 10 to 25% of your sugar and starch, then you would have mycotoxins increased. We didn’t get mycotoxin concentration would be increased. We didn’t create anymore. It’s just that we have less dry matter to dilute out the mycotoxins.
Scott Zehr
Okay, so, I haven’t been lying to people all these years by saying they’re crazy to think they can reduce mycotoxins with an inoculant, is what you’re telling me.
Dr. Larry Roth
Exactly. A good fermentation, the silage inoculates are not going to break down and metabolize the mycotoxins.
Scott Zehr
Right.
Dr. Larry Roth
When the feed comes in from the field that’s the very best that you’re gonna have in terms of quantity of nutrients and the very lowest mycotoxin concentration you’re gonna have.
Scott Zehr
Yes. Yep. Okay, so you gave a kind of a description of the value of using a quality inoculate. Right? But let’s go a little further and talk about the different inoculation strategies that we see on different locations based on… yeah.
Dr. Larry Roth
You know, you bet. Okay. Let’s talk about different inoculation strategies. Again, their overall objective is to get as many nutrients out of the silage storage structure, be it a bunker, upright silo, what have you. And so number one, we ought to drop the pH as soon as we can because the plant’s alive, and it’s gonna start breaking itself down unless we can drop the pH very quickly. And in essence, think of it as pickling the forage.
So it’s corn forage coming in from the field. It’s corn silage after we go through the fermentation, drop the pH. The other place where we can lose nutrients is yeast and mold growth. And this can happen during storage and it can happen at feed out.
So, one inoculation strategy might be to hinder the growth of molds and that would take place with using like […] different acetic acid type bacteria in that they specifically are producing factors that are going to limit the growth of yeast. Maybe not so much to mold, but if we drop the pH we’re typically gonna stop yeast and molds from growing. More or less, more or less.
So strategy number one: produce a lot of lactic acid, drop the pH, pickle the forage so that the plant isn’t breaking itself down. Save the sugar, the starch. Second strategy, limit yeast to mold growth so we don’t get the heating where we get the heat damage protein we talked about earlier.
Plus, we don’t get the yeast growing at feed out and in the TMR where we can lose the sugar and starch. Because the yeast is growing. And anytime we pick up the corn silage or pick up the TMR and it’s warmer than the environment, we’ve got yeast growing. And yeast growing means that sugar and starch that we wanted to go into the cow and make milk it’s now ending up being metabolized by the yeast and making carbon dioxide and heat. I am hopefully not getting too deep microbiology wise, but it’s all about preservation. It’s all about stopping undesirable practices.
Scott Zehr
So, I guess this reminds me of a story. I’m not gonna tell the whole story, but I’ll give the shortened version. And I’ll preface this by saying like, we do not offer an inoculate product here at Agrarian.
So, you know what we’re sharing is experiences. And in Larry’s case, you did spend a lot of time working on inoculates in your previous life. So working with bugs and good bacteria. And I think I’ve shared this story with you. So the quick version of the story is, a number of years ago I was on a dairy that was hosting a silage management presentation, if you would, by a company that sells inoculates.
Dr. Larry Roth
Yeah.
Scott Zehr
And specifically that day we were talking about putting forages in bags and different things we could do to improve how that is kept. The presenter asked the host Dairyman a very simple question, and that was at what rate does he apply his product X. And the dairyman kindly stood up and said, “if you put forage up correctly, you don’t need any of that.” Let’s say crap.
Now, I felt bad for the presenter because he didn’t know that the dairyman was a prospect instead of a client. But what do you say to guys like that? So you know, I gotta believe there’s some truth to that isn’t there of, if we’re putting it up correctly, we don’t really need this because it’s gonna ferment well? But then again, from your experience in, in the years that you’ve worked on inoculates, maybe you have a different view of that.
Dr. Larry Roth
Okay. Fantastic. Great question. So again, to be completely transparent and build upon what you said, Scott, I have spent part of my life in the inoculate world. And I would also be the first one to tell you that you can put up excellent quality silage or haylage without an inoculate. If you have good, healthy plants, you do not have bad bacteria, you do not have high levels of mold in yeast, you do an excellent job of chopping, of packing, an excellent job of feed out, always keeping fresh feed in front of the cows. You do not need an inoculate, in a perfect world.
Unfortunately, Scott, we live in a fallen world and things aren’t perfect. So let’s go back to what is silage worth? It’s worth more than what quite often we put a value on it. So let’s just say, for the sake of argument, that we’re gonna call a ton of corn silage $30, $35. It’s probably worth more than that.
We’ve got a bunker of 10,000 tons, which really isn’t very much. That’s $300,000 or more. Scott, if you had $300,000, would you leave it out in the rain? You’d probably put some plastic over it. Would you leave that $300,000 out there in the wind? You’d probably put a great big rock on it. So are we willing to put $300,000 or more at risk? Assuming that everything is going to go perfect, and you know what the word “assume” is made outta. Okay?
Scott Zehr
Yeah.
Dr. Larry Roth
So yes, I would be the very first one to say, if you get everything right, you don’t need an inoculant. Unfortunately, how often is that gonna happen?
And are we gonna run the risk? Are we going to gamble that we’re going to get everything exactly right? How much are we willing to put that sugar and starch at risk? How much are we willing to risk that we won’t have yeast growing and reducing the availability of the amino acids? That’s the question. So I would agree with the gentleman.
You bet you can put up excellent quality silage and haylage without an inoculant. A few things go wrong. And we lose not sugar and starch. We don’t lose protein. We lose dollar bills. That’s the question. How much are we willing to risk?
Scott Zehr
You know, part of this, and man, this is almost starting to sound like I’m not trying to sell anybody one way or the other, but you know, I’ve seen some of the data right of dry matter or loss, and there’s all these economics that people put together with, you know, buy my silage inoculant.
But listening to your description just now, there’s like an inherent value there to ensuring you have a quality product put up. It’s like you’re broadening your risk range, right? Am I saying that correctly, Larry? It’s you’re giving yourself a little more leeway.
Dr. Larry Roth
There you go.
Scott Zehr
Would say.
Dr. Larry Roth
Exactly.
Scott Zehr
With your forage.
Dr. Larry Roth
Exactly. Yep. Yep.
Scott Zehr
How many times have we said any morning when any dairy farmer anywhere in the world but wakes up, there’s a thousand things that could be going wrong. Right? And I almost see one of those benefits is having a little bit of a buffer to where things didn’t happen quite right today. You know, it wasn’t raining, but it rained during the night and it was a little muddy around the pile, but not real muddy, just little things.
Dr. Larry Roth
When do we decide to start chopping corn silage? Huh? Do we start when it’s a little bit?
Scott Zehr
Well, sometimes it’s when the nutritionist tells us to.
Dr. Larry Roth
Okay. Okay. So do we start when it’s a little bit wet so that by the time we’re done it’s not too dry. So the more water we have in the silage, because we started chopping a little bit later, the more lactic acid we need produced, to drop the pH. Yeah, that would be a good situation to use an inoculant.
And then, boy, we had great chopping weather. It was what, 80 degrees? The wind was blowing. We didn’t have any weather breaks during the course of the week, but those plants sure dried down. And as they dried down, we lost that moisture. And we lost some sugar. We lost some sugar. So now it’s gonna be harder to drop that pH.
Scott Zehr
Yeah.
Dr. Larry Roth
We gotta have it happening really quick. Getting the lactic acid produced. We need the inoculate. Or the other scenario, we start chopping and we get some weather breaks. Are we doing something to keep those yeast and molds from growing? We need to be doing that.
So we could lay out all kinds of scenarios and we could have excellent chopping conditions, but maybe face management at feed out isn’t the best. Maybe we feed our cows only one time a day. And so are we doing something to limit the yeast growing in the corn silage so that our feed doesn’t heat up so much?
So there’s so many different scenarios. I guess I would come back and say, Scott, tell me the challenges that we need to manage for, and then let’s put together a program. So inoculants are not a cure-all. They’re not gonna solve everything, but they’re just another tool in the toolbox to be used along with everything else.
So yes, you can absolutely put up excellent quality silage and haylage without an inoculate. No, inoculants are not cure-alls. They’re not that magic bullet, but they’re just another management tool.
Scott Zehr
So you’ve mentioned lactic acid products, you’ve mentioned acetic acid products.
Dr. Larry Roth
Yep.
Scott Zehr
How do I know which one I wanna use?
Dr. Larry Roth
Okay. Tell me what is our biggest challenge? You know we’ve got pretty good quality corn silage, a lot of sugar, a lot of starch. We’ve got excellent face management. We feed our cows two to three times a day. We’re always keeping fresh feed in front. We do an excellent job of face management on our bunker. Let’s go for that lactic acid inoculate. Let’s drop the pH as soon as we can. So we save as much sugar, starch, dry matter as what we can.
You know, sometimes those corn plants dry down too fast. Our face management just isn’t wet it ought to be due to labor situations, as happens on many dairies we’re only gonna feed one time a day. Then maybe we should think about some of these acetic acid type inoculates. Or propionic type acid inoculants and limit the yeast and the molds from growing. Tell me what are the biggest challenges that we face, and then we’ll pull the right tool out of the toolbox.
Scott Zehr
So, you know, I’ve grown up on the dairy, dad would always put inoculate on. And, you know, small farm upright silo. I would say we weren’t really in the position where we had to really keep track of dry matter tons on basis of like, are we gonna have enough feed to feed the cows? I mean, we had plenty of feed for our land base, for our cows.
But, there was always the question though in dad’s mind, “is this really working?” And, you know, I think there’s a lot of research to say that it’s probably a good idea to do this. But taking out the, is it working or is it not working question, is there a range in between those two of effectiveness, like can we apply this? And it’s maybe not as effective as what we thought it was gonna be and what are the factors around that?
Dr. Larry Roth
Okay. Is your question, is there a range of effectiveness of the inoculants?
Scott Zehr
Yeah. Are there limiting factors of how effective an inoculate can be? I guess is maybe a better way of saying that.
Dr. Larry Roth
Alright, great. First we gotta get the bacteria onto the crop. We gotta do that. So we need to have the right nozzles, we need to have the right application rate. And sometimes adjusting our applicator, be it mounted on the chopper or be it stationary mounted at the blower for the upright silo that you were talking about.
Sometimes that is one of the biggest things that we need to look at. And you look at some of these low volume applicators today, oh my goodness. We’re hardly putting on any volume of inoculant per ton. And then we become dependent upon turbulence and mixing to help it all get mixed throughout.
The other thing that, and I think it’s something that’s so often people ignore, the bacteria once they’re hydrated, they’re living organisms. Before they’re hydrated, they’re like the battery on your car or your truck. You leave the lights on the night before it’s gonna drain the battery. You go to start your car or truck the next morning and you hear “rrr.”
Hopefully you, you at least hear that, might not hear anything. So the bacteria are dormant until they’re hydrated, but they could still be losing their energy because we haven’t handled them properly. Ideally we’re keeping them in the freezer or at least in cool conditions so they don’t use up their energy reserve so that once they’re hydrated, they’re ready to go to work.
And then once we have these organisms hydrated they’re going through metabolism. Does our inoculate have sugar in it to serve as a food or energy source for the bacteria to keep them alive so that once they’re sprayed onto the forage, they’re ready to go to work. Then sometimes when we’re chopping it’s, it gets kind, warm. And you look at certain choppers and there’s a certain brand chopper that I won’t mention, but costs a tremendous amount of money. Extremely good engineering.
Except, they put the applicator tank right under the engine. And if our inoculate solution gets warm, by that I mean, oh, probably 80, 80 to five degrees Fahrenheit or warmer, these bacteria are using up their energy, they’re going to expend themselves and not be ready to go to work when it’s sprayed onto the forage.
So simply taking a frozen pop bottle. And putting that into the tank to help keep the temperature down can go a long ways toward increasing the success of the inoculate. Don’t, don’t put ice in there, ’cause that’s gonna dilute our inoculate solution. But just put that frozen bottle of, of water, of ice in there to help keep the temperature down.
So I would say the, some of the biggest factors related to inoculate effectiveness, application, thoroughness and correctness, and having live bacteria to apply.
Scott Zehr
Okay. You know, going back to kind of the start of this episode, Larry thinking about the mycotoxin side of this conversation, I guess just kind of wrap us up in a, in a bow if you would. We’ve established, right? Especially with DON and zearalenone. Two of the toxins we see the most of. And some parts of the country this year is fumonicin.
Like what we harvest is what we have, as you said, is we have a lot of dry matter shrink we could actually see higher concentration levels. Which, yes, is gonna show up as a higher number on the assay for sure. But, just to reiterate, those field borne toxins like DON, zearalenone, fumonicin, T2, there’s no inoculant out there that’s gonna drop that number, correct?
Dr. Larry Roth
Correct. There’s no inoculant that’s going to break down the mycotoxins.
Scott Zehr
So where we really get into this discussion to where the gentleman that I referenced in the beginning, the dairyman that showed me the article from Popular Press is the Storage Born Toxins.
Dr. Larry Roth
Okay.
Scott Zehr
So I’m just thinking of it like that way. Right? So, you know, I think one of the things you first told me when we started seeing Roquefortine-C come up, albeit folks I know we’re dropping maybe a toxin that some of you guys have never heard of today. Larry and I have discussed Roquefortine-C in the past. Fun fact about Roquefortine-C is that if you’ve ever eaten blue cheese, you’ve probably had Roquefortine.
Dr. Larry Roth
Yep.
Scott Zehr
Or you haven’t. However, that is a toxin that typically shows up in actually really well preserved corn silage piles.
Dr. Larry Roth
Yep. Mm-hmm. Mm-hmm.
Scott Zehr
Right? We maybe didn’t pick it up in the field, but it shows up in storage.
Dr. Larry Roth
Yes.
Scott Zehr
Now just the opposite can happen where we can have maybe poor fermentation or air pockets and we can have molds that proliferate and make some mycotoxins in storage. Or a good inoculate that maybe helps with the fermentation will potentially limit some of those factors. Is that fair to say?
Dr. Larry Roth
Potentially so, yes. So let’s think about what causes a mole to make mycotoxins. Number one, the mold gets stressed. Might be that it’s not growing and that could be a situation where it’s deprived of oxygen ’cause we did an excellent job of packing. Might be temperature. It’s too hot. Sometimes, we’re chopping corn silage when it’s above a hundred degrees Fahrenheit.
We might get some fumonicin if those molds get stressed. Sometimes when it’s really cool, we’re 35, 40 degrees. We might be getting some of the DON being created actually during storage. The Roquefortine-C reference seems to get ironically produced when we have some of our very best silage fermentation conditions, very low pH. High lactic acid.
Everything looks fantastic except dug on it, we got some of that Roquefortine-C. And what’s interesting, Scott, is with all of the mycotoxin assays that we look at, we just really do not see much Roquefortine-C. And so I’m gonna attribute that back to if we can improve plant health generally we have fewer molds.
And that may be one of the biggest things. What can we do out in the field to improve plant health so that we have fewer molds out there, they’re less likely to get stressed if they’re not present. And so less likely to make the mycotoxins, and then once we come into storage, drop the pH in a hurry. But again, we can get Roquefortine-C under some of the very best conditions.
Scott Zehr
I didn’t do a hard count. But to back your point up, I know I said this, I mean, you and I talked about this beforehand, maybe 2% of the samples.
Dr. Larry Roth
Yeah.
Scott Zehr
Maybe, maybe five.
Dr. Larry Roth
I would say five would be at the very upper end.
Scott Zehr
Yeah, it’s not much. So, you know, we test for Roquefortine-C and Mycophenolic acid. Patulin, cetrine, and all these.
Dr. Larry Roth
Yep.
Scott Zehr
Kind of underlying toxins because there, yes, folks, there is research saying that they can have negative effects on your cattle. I think the reason they don’t get talked about much so Larry, is because we see him maybe 5% of the time. I don’t,
Dr. Larry Roth
Yeah.
Scott Zehr
I don’t remember the last time I saw a sample of citrinin and it’s probably been years. I bet it’s been, yeah, three years, four years.
Dr. Larry Roth
Yeah.
Scott Zehr
It’s been a long time. So, you know, I don’t, I don’t want to scare anybody today like, what we’re talking about as far as the roquefortine goes, and some of these other, I’m gonna say lesser known toxins, it’s a very small percentage and it doesn’t come around very often.
So I, I wouldn’t, I wouldn’t go out there if you’ve never used an inoculate. I wouldn’t go out there today to purchase an inoculate with the gold of having less patulin and roquefortin-C in your corn silage, is probably not worth it.
Dr. Larry Roth
Let’s go out there. Let’s do the very best job we can with our silage and haylage, our high moisture corn, any of our fermented feeds. I think in many situations, and again, we don’t sell inoculates here at Agrarian Solutions, but I think that in most situations, a high quality inoculate, note how I described it, high quality inoculant is gonna help you have greater preservation of nutrients.
Then let’s let the chips fall where they may with things like mycophenolic, roquefortine-C and oh, by the way, Scott, we have the DTX concentrate that does an excellent job of defending and protecting against a wide range of mycotoxins. So yeah, do the very best we can with our stored feeds. And then let’s employ the DTX concentrate to defend and protect.
Scott Zehr
Awesome. Larry, you know, I appreciate you jumping on this call today and kind of walking us through that. I know you and I discussed this article at length a little bit and I think it was some good fodder. But also it was, it was good to, I think, have this conversation from the standpoint of, you know, what’s, taking your experience in the inoculate side of things.
What’s the truth? What’s not the truth? And Larry, I’m still gonna stand by whenever somebody asks me if an inoculant is gonna decrease their mycotoxins, I’m still gonna tell ’em, no, you haven’t changed my mind otherwise.
Dr. Larry Roth
Yeah, it’s not, it’s not gonna decrease it.
Scott Zehr
Yes.
Dr. Larry Roth
It may help to limit the growth in the storage structure, but it’s not going to break down the mycotoxin. You’re correct.
Scott Zehr
There you go. You heard it here, folks. All right, Dr. Roth, I appreciate your time today. Thanks for jumping on another episode to ruminate this with me and we’ll be talking to everybody again in a couple weeks.
Dr. Larry Roth
Alright, thank you Scott.
