In this episode we unravel the intricate layers of a cow’s biological hierarchy, where the immune system takes precedence over milk production and reproduction. Discover why immune challenges such as mycotoxins, heat stress, overcrowding, mastitis, and lameness trigger an inflammatory response, leading to a redirection of nutrients towards immune support. We will explore why “reproduction is always the first to go” when a cow faces immune challenges.
Tune in as Dr. Larry Roth shares insights on how understanding nutrient allocation can lead to more effectively optimizing cattle health and productivity. Want to discuss this further? Contact us.
🎧 Listen now to set your herd up for lifelong success!
Scott Zehr
All right. Hey, welcome everybody to the Ruminate This podcast. I’m your host, Scott Zehr. We’re going to be talking about the nutrient resource pie. That is your cow’s TMR or feed stuff that she consumes on a daily basis. And to join in the discussion with me is going to be Dr. Larry Roth today. The Vice President of Nutrition. Am I getting that right? Larry, Vice President of Nutrition here at Agrarian Solutions. Larry, you’d think after with being with the company a couple of years now, I’d remember your job description or at least your job title, your description changes by the day, right?
Dr. Larry Roth
Yes.
Scott
So yeah, we’re going to have a pretty cool discussion here today about when an animal consumes the food you put in front of her today, how she utilizes that. And the factors that go into what she does with that nutrient pie, if you would. So Dr. Roth the first question I have for you on this topic is maybe just give a quick overview of what do we put in that TMR nutrient wise to support that cow?
And the second part of that question is, you know, so the first part is what does she need? And then the second part I’ll ask you to touch on is how does she determine where it goes? What, what goes into that biologically or so on?
Dr. Larry Roth
Okay. Well, that’s a big question. I won’t get into nutrient requirements, but we can basically break it down to she’s got energy. There may be coming from the starch, formidable carbohydrates, the fat that she’s consuming. She’s consuming protein, amino acids, nitrogen, that’s going to get turned into microbial protein, the ideal amino acid balance, and then the minerals, the vitamins and other factors that she’s consuming.
We’re feeding the cow, but to an extent we’re feeding the rumen? Some of these nutrients are going to get process. Some will get improved in the rumen, others will be degraded. And so we get into all kinds of things. You know, what can we do to protect nutrients in the rumen? What can we do to synchronize energy and nitrogen availability to help make more microbial protein?
But yeah, we think about we’re feeding the cow, but really we’re feeding the rumen and then we’re feeding the host animal. Then the second part of your question was… What was your second part, Scott?
Scott Zehr
Yeah, no, that I’ll stick to one at a time here from now on. The second part of the question would be, once she does consume that TMR for the day, she’s processing those nutrients in the rumen, and subsequently the rest of her stomach, small intestine. How does she determine where those nutrients end up? Is there a hierarchy of needs just naturally?
Dr. Larry Roth
You bet. Yeah, certainly the cow has a hierarchy for how the nutrients are used. First thing she’s going to do is think about staying alive. You know, she’s going to have maintenance requirements and I’m going to put the immune system as part of that. So when she has an immune load on her, for whatever reason, that’s going to cause more nutrients to come over here to just basically staying alive.
Then we think of the first and second lactation animal is also going to have nutrients that are going to go into growth. Hence the importance of having these animals big enough by the time that they freshened so that more of the nutrients can go into productive purposes as well as just growing.
And then she starts thinking about making milk. I mean, she’s wired by nature that she’s supposed to take care of a calf that’s standing beside her. In our dairies, there is no calf standing beside her, but she’s still putting milk or putting nutrients into milk. And then the very last thing standing in line is making a calf for next year.
So reproduction is the very last thing that she thinks about. But that’s what we need her to do. Get pregnant and stay pregnant so that we have a calf next year. So she’s producing milk for that next lactation. So always think of it as staying alive. And I’m going to put the immune system in with that part of that maintenance requirement, which may not be exactly true because that’s going to vary.
And with maintenance there’s also going to be nutrient requirements for heating her during the winter and then cooling her during the summer and then growth and then lactation, and then finally reproduction.
Scott Zehr
That hierarchy of needs there’s determining factors, if I’m understanding you correctly, of where she’s going to allocate nutrients. You started to touch on it. If she has an immune load or you know a challenge to her immune system, she’s going to pull nutrients one way or the other depending on how she sees fit. Can you describe for us maybe what type of immune challenges she deals with on a daily or sometimes region or a yearly basis, if you would.
Dr. Larry Roth
You bet. Yeah. Well, we can start with on a daily basis. You know, she’s always exposed to respiratory pathogens. She’s exposed to allergens that she’s breathing in. So the immune system has to defend the respiratory tract. Probably the largest immune organ in the body is going to be the digestive tract. If we start thinking about square, inches or square millimeters, it’s going to be the digestive tract.
She’s consuming pathogenic bacteria, viruses. She’s consuming protozoa that are going to be pathogenic. So she has to defend herself against that. And then we have things that happen that cause us to lose the tight junctions in the small and large intestine where the cells come together. Things like dehydration, heat stress, other things that come along.
And then what was a tight junction, a very important part of the digestive tract as an immune organ, now those are open and they’re an interstate highway for the bad stuff to drive right into the body. And so we start thinking of the skin as well as being an important part of the immune system.
Her different parts of her body are there to defend her against invading agents getting in. So again, her immune system has to deal with things on a moment by moment basis and those challenges can vary as we go through the course of the year. It’s winter time and the birds come to roost in the freestyle.
They’re out there at the corn silage bunker, pecking all the corn out and they leave their droppings as a thank you for giving them a place to live. We think of Clostridia that may be coming from the Haylage that were incorporated back during harvest. So, man, the body is always under all of these different challenges and then we have things like calving, where we have changes in internal tissues.
You know, we had the free radicals and free radicals aren’t people that escaped from Berkeley in the sixties. It’s these electrically charged particles that bounce around inside the body like a cannonball destroying other cells and tissues. And so it’s so dynamic what is going on in the body on a moment by moment basis, depending upon what the challenge is.
But the cow is so uniquely designed, just as we are, to have so many different elements of the immune system to defend her. But she’s got to have energy, she’s got to have amino acids, she’s got to have trace minerals, vitamins, the antioxidants, all of these things come into play for supplying the immune system.
I think of the immune system as being the body’s military, and if that military is starved for resources, it’s not able to adequately protect the cow. But if we can appropriately supply the immune system, it ultimately protects her better so that nutrients can go for what I’m going to call more productive purposes, lactation and reproduction. And in some situations, really, we should consider growth to be a productive purpose because she doesn’t have to grow after.
Scott Zehr.
Right.
Dr. Larry Roth
So Scott, we think of the importance of cooling. Cooling helps to repartition nutrients to the cow is not heat stressed. We’re better able to maintain the tight junctions, we don’t have stuff getting into the body and so consequently nutrients can go to more productive purposes.
Same with keeping an animal warm in the wintertime. Same with keeping an animal comfortable. Anything that stresses the cow, anything that raises cortisol levels is going to change the other hormones, are going to change the flow of nutrients. So, cow has a set, set of resources to work with. We just have to be thinking about what are the factors that she’s dealing with and how is she going to shift those set resources.
Scott Zehr
It brings me to my next question. You know, when I’m on a farm with say the whether it be a nutritionist, a veterinary, or just one on one with a herd manager, herd owner we talk about things that cause inflammation. And a lot of times I have my big five that I talk about a lot and I talk about, you know, mastitis and lameness and overcrowding, heat stress, mycotoxins.
You’ve, you’ve mentioned a little bit of some of those things, but those five things together, what kind of drain does that put on that immune system? And what are some of the things that we could expect to happen production wise and reproduction wise when we have factors like that, then I’m going to say, outside of certain parts of our country where heat stress is just, it’s going to be there a lot. A lot of those things we can really do a really good job controlling like lameness, mastitis, mycotoxins, which we’ll get into. So your thoughts on that.
Dr. Larry Roth
Well yeah, you know, we talk about inflammation. Inflammation is a normal part of the body’s response to different challenges. The cow has a calf and the uterus has to shrink tremendously. Well, there’s changes in tissue. There’s elements of the immune system we can think of having, helping to get rid of those cells.
All of that comes into play. We think of inflammation due to heat stress and what it has on the developing calf inside the cow. And I guess I should have talked about that a little bit more when we talk about nutrient repartitioning. And I guess in my mind, I was lumping the developing calf inside the cow into the reproduction phase.
But the last third of her gestation is the time of greatest fetal growth. She needs energy. She needs amino acids. She needs minerals. She needs vitamins for the developing calf. And so that shunts nutrients away from making milk and there’s all kinds of things going on hormonally that maybe a little bit outside of our scope for this conversation.
And you know, I keep talking about energy. And in some ways I’m thinking about glucose, Scott. And we think of glucose as needed to make lactose. Lactose has a relatively window, as being part of milk. And we can simply say no glucose, no lactose, no milk. Well, glucose is needed for any rapidly developing cell in the body, be it the follicle that’s going to be releasing the egg to be fertilized to turn into an embryo, and then we need glucose to help that keep developing.
So you’ve got this constant competition for nutrients. What is her biggest challenge at the moment? And we always come back to her hierarchy of needs. Stay alive, the immune system, growth, make milk, reproduction. And again, I’m going to include the developing calf in that. So we can make this very complicated or we can make it very simple.
What is she dealing with today? What is the challenge? And I’m going to say challenge, Scott, because stress implies mismanagement. Well, changing the reproductive tract after she has a calf isn’t really a stress. It’s a challenge. It’s going to happen but she’s got to deal with that so that she can get on with other, other parts of her life, shall we say.
Scott Zehr
Yeah, you know what, what you’re talking about here reminds me of, my days with reproduction consulting and, the thing is repro is always the first to go. And so what you’re talking about is if we’re struggling getting cows pregnant, certainly there’s a whole litany of things that go into getting cows pregnant.
When I was taught how to breed cows by Doug Baker, he told me, “In order to get a cow pregnant, you have to have the stars align. And the moon has to be right and the sun has to be right. It’s almost an act of God.” And he’s not that far off in reality. Cause there’s things like the way we inseminate cattle, the types of heat detection methods we use, so on and so on.
Speaking nutritionally though, if we’re seeing repro on a slow and steady decline, or even if it’s just, an event where this month we didn’t get cows pregnant, nutritionally speaking, what is that telling us?
Dr. Larry Roth
You bet. Yeah. So, we’re dealing with nutrition challenges right now, here today. But those challenges can be reflecting on what happened before.
There’s research that says, whatever happens to the cow the first three weeks of lactation, after she’s gone through her most stressful day of the year, is going to affect when she gets pregnant, and if she stays pregnant, even 200 days in milk. I mean, it’s, that’s amazing.
Scott Zehr
Yeah.
Dr. Larry Roth
And so when you start thinking about that, little, I’ll say little, maybe, there may be big challenges that come early on, influence her partitioning nutrients, her repairing her body, her hormonal balance as much as 200 days later.
So it points out the need to prepare the cow adequately for calving, and you’ve heard me say this before, that’s her most stressful day of the year, and then how does she respond to that? So it makes it so important, I think, that we’re walking cows, we’re watching cows, we’re using cow activity systems that start to tell us when her activity, be it eating and ruminating or moving around, little changes that we start to see there, the quicker we can get in there and head off metabolically what the challenge is, it ultimately helps to get new nutrients partitioned to more productive purposes.
And I just think this is mind boggling, some of this research suggesting that it’s that first three weeks after she perussion, that is going to have such a very long term impact on whether she gets pregnant or not. You know Dr. Mike Hutchins…
Scott
It always comes back to, it always comes back to the beginning, right?
When it, I always say if, if we’re struggling on first service conception rate, let’s go back to the dry period. Look at that refresh period. Look at that first three weeks after calving.
Dr. Larry Roth
Yep. Back up. And what happened before? Cause what we’re dealing with today is determined by what came before.
Scott Zehr
Yeah. You were getting ready to mention something, Dr. Mike Hutchins maybe?
Dr. Larry Roth
So Mike Hutchins famously talks about how you have only one chance to set that lactation curve. And if you have changes, challenges in that first 21 days, maybe we say first seven days, whatever, you’ve altered that lactation curve for that lactation.
She’s never going to peak as high as she could have. She’s never going to be as persistent as what she could have been. And so to me, a lot of this comes to her ability to respond to challenges and how that affects nutrient repartitioning.
Scott Zehr
Larry, there’s a question I wanted to ask you about these different challenges like mastitis, lameness, overcrowding, heat stress, mycotoxins, you know, things that we can manage kind of on a farm level. How does a cow handle them? Do you kind of handle them equally? How does that work?
Dr. Larry Roth
Well, that’s a really good question. Are all challenges responded to in an equal manner? And I think we’ve got to say no.
It depends on the severity of the challenge. It depends, I think how central it is to her staying alive, first of all, because again, that’s her first hierarchy. And she may, I hate to say slough some of these challenges, but she may get rid of some of her needs so that she can stay alive. For example, with the loss of an embryo, why did she do that?
Well, she didn’t have the nutrients to keep it alive, so that was maybe not a challenge, but that was a need. And she says, “I got to stay alive, so I’m going to have to get rid of this developing embryo so that I can stay alive. I got to make milk.” She’s wired again for that cap standing beside her even though there isn’t a cap there.
She’s still wired that way. One of the biggest challenges is what happens in the digestive tract, the small and the large intestine. Again, I like to think of the digestive wall as being like a castle wall. Think of that medieval castle where it’s protecting the people who live inside the castle against the barbarians outside.
And the barbarians are trying to make any little hole in that castle wall so that they can get inside. Well, that’s the way it is with pathogens. That’s the way it is with mycotoxins. That’s the way it is with endotoxins that are created by organisms in the small intestine. They’re all trying to some degree, make a hole in that castle wall, the digestive tract lining, so that they can get into the body.
And once they get into the body, then there’s a major immune challenge that is enacted to defend the body. Ultimately, the liver is the body’s biochemical factory. It has responsibilities for detoxification. It has responsibility for making glucose and shall we say reprocessing other nutrients.
But if this liver is having to deal with, for example, mycotoxins, doing a major detoxification, nope, it’s not going to be as efficient. If we have the fresh cow, she was a little bit over conditioned and we have fatty acids being released, in certain body tissues, and those fatty acids are flowing to the liver for reprocessing, if we can think of it that way, into making glucose, well, now that liver is trying to do so much, and it’s going to be inefficient at all of these different things.
So, you know, not all challenges are created equal. And it may be in a little bit of a function of what stage of production is she at.
Scott Zehr
Good point.
Dr. Larry Roth
And so consequently, the importance of cooling that we’ve seen. University of Florida research and others. Inflammation due to heat stress during that last third of gestation, it affects the calf inside of the cow at that moment. And it can affect even the granddaughter of the cow.
Scott Zehr
The developing gonads.
Dr. Larry Roth
Heat stress at that moment. So it just gets kind of mind boggling how the cow responds to different stressors. I think there’s places where we can say stressors like heat challenge. Heat stress can be considered a stressor and then challenges, normal things that take place.
For example, changes in ruminal pH, we get endotoxins produced. We get challenges that come from that. So really Scott, it gets to be a mind boggling series of challenges and stressors the cow is dealing with and it all impacts what is she doing with the nutrients that the cow consumed?
What is she doing with the nutrients that the producer paid for? Paid for and now the cow is saying okay I got to use the nutrients for this thing and that thing that may be different than what the producer intended Those nutrients to go into.
Scott Zehr
Yeah, I think we just covered three more topics for podcast ideas in the future with a lot of our conversation here today.
You know, one other thing because this is, Larry, I’m going to say this is what we do at Agrarian. So that mycotoxin challenge, we talked about it in episode two, part two, where we saw an improvement in reproduction pregnancy conception rates. So if I’m understanding what you’re describing here today, correctly, right?
Why did she lose that embryo? She didn’t have enough nutrients to support that pregnancy. Her body said, “Hey, I got to stay alive. So we have to move on from that.” Would it be fair to sum up our improved pregnancy success in the research trial, really as simply as we freed up nutrients to support that pregnancy by taking an immune load off that cow?
Dr. Larry Roth
I think so. I think it would be. And I’m going to take it a step further. I think that we enabled more nutrients to be available for reproductive success because we did a better job of defending the castle wall. We helped the intestinal lining cells be able to reject mycotoxins as part of our theory of how we work.
So consequently, nutrients didn’t need to go into repairing the intestinal cells. Nutrients didn’t need to go into the immune response. But I think also, Scott, if we had a healthier intestinal lining, the animal’s going to be more efficient at absorbing some nutrients as well. So, absorb a greater quantity of nutrients, and then the nutrients that are absorbed, are going to be partitioned to more productive purposes.
We talked about it in the first part of our conversation about the DTX research. With first lactation cows, we did not see a statistical increase in milk production. So what did they do with those nutrients? Well, we didn’t weigh the heifers. Okay, we didn’t weigh those first lactation cows.
Did they take some of the nutrients that they had? I’m saying that they probably absorbed a greater quantity of nutrients, having a healthier intestinal lining. Did some of those nutrients go to growth? Well, we don’t know because we didn’t weigh the first lactation cows, but we really did have a statistical increase in reproductive success.
More got pregnant and stayed pregnant. So that was a use for the nutrients that were available. Greater quantity of nutrients absorbed, I’m going to theorize. Plus, we had nutrients now that could be partitioned off for productive purposes. Didn’t happen for milk production, but it certainly did happen for reproductive success.
Scott Zehr
Awesome. Well, Larry, I appreciate you joining the conversation today to talk about that nutrient pie that is the feed stuff we put in that cow every day and how she determines where those nutrients go. It certainly has challenged my way of thinking about that in terms of that hierarchy of needs, the immune system body growth, production and lastly reproduction and answers a lot of questions, especially the age old question or the age old statement rather: repro is always the first to go. Now we kind of understand why. Yeah. So again, Larry, thank you. And I will see you again on the next podcast.
Dr. Lary Roth
All right. Thank you, Scott. Appreciate it.
