Most people see “calcium carbonate” on a label and assume it’s all the same, cheap limestone that barely gets absorbed. However, now we know: Not all calcium carbonate is created equal.
In this episode of Ruminate This, Scott Zehr sits down with Dr. Larry Roth to answer the questions producers and vets are really asking:
What’s the difference between Calcium Carbonate and Calcium Chloride?
Why Is seaweed-derived calcium actually more bioavailable?
Will I see an ROI with a calcium bolus at calving?
Agrarian Solutions is a technology company that takes complex science and makes it usable on your farm. Just like Windows made DOS simple, we’re here to make advanced animal health innovation practical, profitable, and impossible to ignore.
🎧 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 am going to be joined by none other than my good friend, mentor, Dr. Larry Roth, the Vice President of Nutrition here at Agrarian Solutions.
So Larry, I sometimes find it really hard to stump you. You know, you’ve, you’ve been around more years than I have. You’ve seen a lot of things. It is not very often.
Dr. Larry Roth
That’s way of saying, that’s a nice way of saying I’m old.
Scott Zehr
It’s not very often I get to stump you, but I’m gonna try right now.
Dr. Larry Roth
All right
Scott Zehr
Okay. I’m gonna try really hard. And so you’ve heard the analogy that all coconut trees are palm trees, but not all palm trees are coconut trees, correct? Okay, and I promise Larry, and to the listeners, I’m gonna get somewhere. All sweet corn is corn, but not all corn is sweet. Okay. All right. You probably… Okay. How about all champagne is sparkling wine, but not all sparkling wine is champagne.
Okay. This is one that we should all be familiar with in our industry. All kobe beef is beef, but not all beef is kobe. There. Okay. All diamonds are rocks, but not all rocks are diamonds. Okay. One thing I’ve learned in the, in the world of maple syrup, because we do bourbon infused syrup, is that all scotch is whiskey, but not all whiskey is scotch.
Okay? Uhhuh, all Stratavaris violins are violins, but not every violin is a Stratavaris. That’s probably one of my favorites.
Dr. Larry Roth
Okay.
Scott Zehr
This one I find kind of silly is probably not gonna stump you. But because my wife uses a lot of parchment paper in the kitchen, all parchment paper is paper, but not all paper is parchment.
I thought that was kind of a weird one, but. So why do I bring all that stuff up? Right? Larry, I think that we at Agrarian, really the, the team that you lead on the, I’m gonna say the, the research, the technical side of things. You know, it’s like we, we really are, I, I recently wrote an article about how innovation is, looks a lot like Agrarian anymore in today’s world.
And I say that because when you look at the things we’ve done with Cow Start Complete, which we’re gonna touch on some components of that today. When you look at things like the plant actives that we’ve added to DTX. That’s groundbreaking stuff, right? That’s new cutting edge technologies.
And, you know, I don’t know if anybody would really call Agrarian a technology company because when we think of technology, we think of Silicon Valley, stuff like that. But I do, and the reason I do in this context in particular is because, so like, you know, the science behind animal health can be pretty complex, right?
Whether it’s, we’re talking calciums or rumen chemistry. But I view what you do for us on the technical side and lead up, I guess the training of guys like me to talk about this stuff is taking that complexity and basically making it easy. Almost like when we had computers that ran on dos and then Windows came along? To the point that I don’t need to be a computer programmer to run a computer today. Right?
Dr. Larry Roth
Right.
Scott Zehr
And I also think that there’s a lot of producers out there that don’t need to be a biochemist to run a healthy herd when they work with us. And I think that’s a big part of what you’ve been able to help us do. And so I, I think it’s fair to say that part of our mission is taking that cutting edge, what’s backed by science and translating it into actionable, understandable stuff that we can use in the barn, we can use in the parley, we can use in the feed bunk.
And I think people, I think people genuinely appreciate that. It’s a long-winded, maybe segue way into what we’re going to be talking about, but the last analogy I wanna throw at you. All limestone is calcium carbonate. Not all calcium carbonate is limestone.
Dr. Larry Roth
Correct.
Scott Zehr
What the heck am I talking about with that?
Dr. Larry Roth
Oh, what are you talking about? You’re talking about the differences really, between chemical structure, chemical composition, and physical structure. That’s what you’re talking about. And, let’s jump ahead here a little bit. What’s this got to do with anything? It’s got to do with the calcium that is in the Cow Start Complete.
Scott, we’ve talked on this call about one of the special features of the Cow Start Complete transition Bolus is the, I’m gonna try and pronounce this right, Scott, lithothamnion Seaweed, and really we should be calling it a Macroalgae. I mean, there’s different types of algae.
There’s algae that can grow in a pond or any place water accumulates. But it doesn’t have roots, doesn’t have stems, doesn’t have leaves. A macro algae is like what we call seaweed. It’s got roots, it’s got a stem, it’s got leaves, and that’s what we harvest from the sea around Iceland. A macro algae, but in our language we’re, we’re just gonna call it seaweed.
Okay. Just call it seaweed. So what? Well, Scott, let’s back up to the Cow Start complete bolus. What’s our objective? Always like to think what’s our objective with anything that we’re trying to do. The objective,
Scott Zehr
launch her into lactation, right?
Dr. Larry Roth
Exactly.
Scott Zehr
The critical first 48 hours.
Dr. Larry Roth
But to do that, Scott, I’ve gotta get certain nutrients into her blood system, into her cells. And the only way that’s gonna happen is having these nutrients available to be absorbed from the digestive tract, be it the rumen, be it the small intestine. So we have to have these nutrients bioavailable, fancy word that just means that they’re available to be absorbed. So let’s come back to our lithothamnion macroalgae seaweed. Scott, let’s just save time and we’ll just call it seaweed. Okay?
Scott Zehr
Yeah.
Dr. Larry Roth
So seaweed has calcium in three different forms. Forgive me if I start to nerd out here, but I’ll…
Scott Zehr
I’ll reel you in if you do.
Dr. Larry Roth
Okay. But it’s calcium carbonate. Okay. Calcium carbonate. Calcium, a carbon, and three oxygens. That’s what we’re talking about. Calcium carbonate. So there is a biological form of calcium carbonate, and we call that aragonite. Okay. Aragonite is very available form of calcium carbonate because its physical structure when you get a whole bunch of these calcium carbonates together is aragonite. Rumen fluid or water is able to access the calcium carbonates.
So what? Well, we’ve gotta have rumen fluid in the rumen getting into the aragonite to solubilize the calcium carbonate. So that number one, you got the carbonate to help with rumen pH, which we want to have up. And we want to have the calcium available. Okay? So what form is that calcium carbonate? Aragonite. It’s available, very available.
Now, what happens over time is Aragonite turns into Vaterite starting with a V. Vaterite. Vaterite has a different chemical or has the same chemical structure, calcium carbonate as aragonite, but it has a different physical structure. And with that physical structure, rumen fluid is not as able to get to all of the calcium carbonate, so it is not as available.
Also, interestingly, magnesium comes into play with this stuff also. So we’re talking about calcium and magnesium bioavailability. All right? So our seaweed has aragonite. It has vaterite and then it also has the final form of calcium carbonate, calcite. Calcite is, in essence, like a brick. It’s all solid. Rumen fluid isn’t able to get there, isn’t able to solubilize the calcium carbonate, so you have the calcium available to be absorbed and the carbonate to help buffer the rumen.
Okay. So I started out by talking about seaweed and, and biological, but what happens is pressure. Think about pressure the deeper you go in the ocean. Think about when sediment starts falling on things. Okay? You have all this pressure, compacting it. Well, Scott, we could go out and we could mine limestone.
There’s different places where you have an ancient seabed and all of this macroalgae, seaweed, long time ago was growing and sediment came and packed all of this seaweed down. And guess what? It’s calcium carbonate, but it’s calcite.
Scott Zehr
My house is built on calcium carbonite.
Dr. Larry Roth
It’s built upon calcite. Yeah, it’s built on limestone. Yeah. And Scott, that calcite that your house is built on, at one time was aragonite. When those plants, macro algae were alive. Okay? So it transitions over time. So, you were making a comment earlier that all coconut trees are palm trees, but not all palm trees are coconut trees, if I remember correctly.
Scott Zehr
Yeah.
Dr. Larry Roth
We can say the same type of thing with our discussion today relative to Cow Star Complete. All limestone is calcium carbonate, but not all calcium carbonate is limestone. Or maybe let’s make this a little bit more correct. All calcite is calcium carbonate, but not all calcium carbonate is calcite. Okay.
Scott Zehr
So, okay, so I wanna stop you here. So, why are we even talking about this, right? Folks, if you’re, kind of listening to this and you’re saying, why are these guys talking about calcium carbonate, anyway? So let’s dive into that part of it a little bit, Larry. You know I, I think if you look across US dairy supplement products today such as calcium products. Yes, we’re gonna see calcium sulfate. We’re gonna, you know, the calcium salts type stuff. We’re gonna see calcium phosphate, we’re gonna see tricalcium phosphate, different ingredients, different forms of calcium. We’re also gonna see, and we’ve seen it for years, right? Calcium carbonate.
Dr. Larry Roth
Yep.
Scott Zehr
And what have we always been told about calcium carbonate?
Dr. Larry Roth
Not available.
Scott Zehr
It’s got poor bio, bioavailability.
Dr. Larry Roth
Yep.
Scott Zehr
And it takes the cow forever to digest it because of that reason. And there’s, I think you cited a study in, in a previous meeting that we had from 93, I believe it was, that showed you can feed her all the calcium carbonate you want, but you’re not gonna get ionized calcium levels high enough by doing that.
Dr. Larry Roth
Yep.
Scott Zehr
So, you know, the word calcium carbonate in today’s dairy industry is almost derogative. It’s like, oh, that’s that cheap stuff that people put in there just to try to boost numbers on a label. Or fill up the bolus or whatever the thing may be. And I, I think a lot of the industry knows that, but then you go look at our Cow Star Complete label, and I think that’s where I think this is such a great opportunity for us to get this message out to people that not all calcium carbonate is created equal. Right? And you know, this use of the seaweed technology and what it’s bringing other than calcium. ‘Cause that’s really what makes Cow Star Complete special.
Dr. Larry Roth
Correct.
Scott Zehr
It’s bringing a law and a great bioavailable calcium. Talk to us a little more about what else it’s bringing.
Dr. Larry Roth
All right, so the seaweed brings not only calcium and magnesium, which are important. But 72 other minerals. We could call ’em macro minerals. There’s a little bit of potassium there. But more importantly, the trace minerals, things like zinc, copper, cobalt, others.
These trace minerals are so important for supporting immune function and serving as co-factors with enzymes. You have to have enzymes to go through basic metabolism, take a nutrient from this form and convert it over to another form. You gotta have so many of these co-factors. So, we talk about needing trace mineral nutrition to support the immune system, which helps us to resolve inflammation.
Well then with Scott, we gotta think about what form are these trace minerals being supplemented, and are they going to be available? Okay. Congratulations. You’re feeding seaweed and it’s got all of these trace minerals. How do you know that they’re gonna be available? Well, what type of a structure are these trace minerals embedded in? They’re embedded in this aragonite and this Vaterite, which are going to break down at a much faster rate than calcite. That’s where this all comes into play.
Scott Zehr
So yeah, you can find trace mini trace minerals in any calcium carbonate. Just whether or not the cow can get to it, right?
Dr. Larry Roth
That’s right. What’s the bioavailability? And how long does it take for those minerals to be made available? Yeah, and I think that’s what makes this seaweed or macroalgae so unique is that there is calcium carbonate, yes. But it’s in the form of aragonite, which is gonna break down at a much faster rate than the calcite.
So you get the calcium, you get the magnesium availability. But I’ll go ahead and say maybe more importantly, you’re gonna have all of these other 72 minerals available to support immune function and to support basic metabolism by serving as co-factors. So that’s where all of this becomes important. Now, somebody may be really into this lithothamnion seaweed or macroalgae and understands that yes, it is the calcium, there is a form of calcium carbonate. So it’s not available, correct?
No, it is available because it’s there as aragonite. So what is the form of the calcium carbonate? Is it available or not? If the calcium carbonate is calcite, it’s not available. And all of the other trace minerals embedded within that structure are not gonna be available as well in rumen food.
So I, I think, Scott, we have to step back and explain maybe what is found on the label of the Cow Start Complete. Because you’ve got the seaweed there and we talk about it being a major source of the features and benefits that we’ve got. And a person could say, well, that’s not gonna be available. Yes, it is, because of the form of the calcium, the calcium carbonate, very bioavailable form.
And so it’s gonna break down, solubilize much faster than other forms so that now all of these minerals are gonna be absorbed. And Scott, you, you go to the recent study that was conducted at a 5,000 cow dairy, and what we saw was that when we compared two oral calcium products, one that was based upon calcium chloride, a calcium salt, and calcium salts are very quickly available.
And I wanna come back and talk about that some more in a little bit. So remind me of that. There was a competitor bolus based upon calcium chloride, and then there was a competitor calcium drink, and they had several other minerals and so forth in there. And it was all based upon calcium, salt, calcium chloride. Breaks down very quickly, dissolves almost instantly.
Wow. That’s gonna beat the Cow Start Complete based upon this seaweed. It’s going to beat the Cow Start Complete for boosting blood plasma calcium with these cows. Right? No. When we look at this study, there was no difference in blood calcium levels. They were all normal calcimic. In other words, two millimoles per liter of blood or higher from calving all the way through 96 hours. No difference.
Scott Zehr
Yep.
Dr. Larry Roth
Okay. One’s based upon calcium salt, calcium chloride is available. The other is based upon calcium chloride or calcium carbonate, that’s not gonna be available. Yes, it is. Because it’s aragonite. Yeah. So that, that, that’s why we’re having this conversation. So that if somebody says, wow, macroalgae seaweed, that’s based upon calcium carbonate, yes it is.
But it’s based on a bioavailable form. Consequently, all these other items are going to be available. So we may be getting off into, I hate to say it, the seaweed here, the seaweed, we’re all nerdy on this, but we have to explain what is the form, the physical form of the calcium that is in the seaweed that enables it to perform so well, and in fact perform as well as a calcium salt. Calcium.
Scott Zehr
Well, and I think, I think it is important too because, you know, if you, know, I made the comment, calcium carbonate is this cheap source of calcium, Right? That we’ve used in numerous products throughout the last number of years in dairy.
Dr. Larry Roth
Yes.
Scott Zehr
And you know, really what I’m talking about is limestone. Uh, pulverized limestone. And I think that’s, it’s important to understand what you’re paying for when you look at Cow Start Complete.
Dr. Larry Roth
Absolutely.
Scott Zehr
And if you’re going to compare calcium chloride to a bolus that uses calcium carbonate derived from limestone, it’s gonna be more expensive. And if you’re gonna absolutely compare Cow Start Complete to, you know, that other bolus, it’s also gonna look more expensive.
Dr. Larry Roth
Yes.
Scott Zehr
But Larry, I wanna ask you this question, this is something that I, I’m just gonna ask the question. Consumers, we all look at price. But now let’s segment off into producers. Looking at the cost per bolus. Shouldn’t we be looking at the cost per successfully transitioned cow?
Dr. Larry Roth
We should be looking at what is our objective and accomplishing the objective. Scott is the objective to have the most inexpensive form of calcium? Or is the objective to successfully help the cow transition into lactation?
Scott Zehr
I think that’s fair to bring up objective Larry. and I would like to hope every producer out there is focusing on a successful transition program for those cows. Cause it, they just need to be. But I think my, the point that I’m trying to get across is that the price that you pay for a bolus, honestly is irrelevant if you achieve a successful or more successful transition program. Because it just allows that cow to do so many more things once she gets post calving.
Dr. Larry Roth
Right. Yeah. And, and again, I always keep coming back to what is the objective? Is the objective just to get blood calcium up? We might be able to do that with a calcium salt, calcium chloride. Although the research does not indicate that. Or is our objective to successfully and in a healthy manner, transition the cow into lactation?
And Scott, I think that many of the calcium salts, calcium chloride fail in that. Because they are not addressing the inflammation, the immune need, the antioxidants needs of the cow. So we have to be thinking about it’s more than just calcium. It’s all of the other minerals, all of the other antioxidants that the cow needs to successfully transition into lactation.
Scott Zehr
So Larry, to your point, and for the listeners, if you go to episode 54, the Next Generation of Transition Cow Care that launched on September 1st, 2025, we talk about over 20 studies that were done with calcium salt type products like calcium chloride that showed calcium all by itself, does nothing to improve milk production, reproduction, body condition.
Dr. Larry Roth
Let me maybe tie up some of our discussion here on calcium this way. We can have Aragonite, Vaterite as calcium carbonate and it’s kind of like a sponge full of calcium that we can squeeze the calcium out.
We could have our calcium carbonate in the form of calcite like limestone. And limestone is a hundred percent calcite and as hard as a brick. You can’t break the calcium out. Maybe in a long, long time you get a little bit out. Or you could have a calcium salt. It’s instantly available almost like a sugar cube that dissolves so quickly, but it’s gone. And not able to give the animal really what is needed.
So again, I’m gonna come back to what is our objective? Is it to just kind of calcium quickly available? Or is it to provide the base to launch the cow into lactation? And if our goal, our objective, is to launch the cow into lactation, let’s look at the seaweed with the aragonite and the Vaterite that’s gonna make these 74 minerals available relatively quickly in a sustained release manner. Okay? I think that’s what we want to do.
Scott Zehr
Larry. I appreciate you taking time today to do this because you have given me in particular something to think about, something new to understand, and I appreciate that. But you’ve also kind of made me feel a little more okay with how hard I’ve been on calcite in the past and I will go back to what I’ve said before. The best use of that is to put it in my driveway and use it as a base and drive over it.
Dr. Larry Roth
Scott. It comes back to your objective. Your objective was to have a road base that you could drive on and not get stuck in the mud.
Scott Zehr
Yeah.
Dr. Larry Roth
Go with Calcite.
Scott Zehr
Yep. And let the seaweed derive calcium that you find in Cal Star Complete take care of the subclinical milk fever.
Dr. Larry Roth
There you go. You got it.
Scott Zehr
I like it. I like it. Larry, if you could just send our audience home with one takeaway today, what would it be?
Dr. Larry Roth
Well, just with one takeaway. Seaweed is a source of sustained, released, bioavailable calcium and 73 other minerals.
Scott Zehr
I like that. And my take home today is all limestone is calcium carbonate, but not all calcium carbonate is limestone. There you go.
Dr. Larry Roth
Great one.
Scott Zehr
Take a look at agrariansolutions.com. Check out our website for our new next generation of transition cow care bolus called Cow Start Complete. Dr. Roth, I appreciate you taking time outta the day again today and we’ll be talking to everybody again soon.
Dr. Larry Roth
Alright, thank you Scott.
Scott Zehr
Thank you.
