Guests: Dr. Lance Baumgard, Iowa State University, Dr. Rosemarie Zimbelman, Dairy Nutrition Services, Dr. Bob Collier, University of Idaho Summer heat is at full strength and that means heat stress for your animals. Tonight, we have brought together a powerhouse roundtable of experts in the field of heat stress management to talk through the physiology and mechanisms for effectively managing the heat.
Guests:
Dr. Lance Baumgard, Iowa State University
Dr. Rosemarie Zimbelman, Dairy Nutrition Services
Dr. Bob Collier, University of Idaho
Summer heat is at full strength and that means heat stress for your animals. Tonight, we have brought together a powerhouse roundtable of experts in the field of heat stress management to talk through the physiology and mechanisms for effectively managing the heat.
Dr. Bob Collier discussed how we have changed our cows in the past 50 years to produce milk production which increases maintenance requirements, making them more sensitive to heat stress and more resistant to cold. 2:50
Dr. Rosemarie Zimbelman discussed some of the advancing technology seen over the past 40 years such as evaporative cooling methods and nutritional strategies improving cattle comfort. 6:10
Dr. Bob Collier discussed the possibility of higher sweat rates in cows but also the negative effect which would be lower milk yields. 16:38
Dr. Rosemarie Zimbelman discussed altering diets in the summer months to reduce heat stress. 20:00
Dr. Lance Baumgard discussed the consequences of heat stress emanating from the gut (leaky gut). This causes an immune response, leading to heat stress and infections like mastitis. 22:06
Dr. Bob Collier discussed the advantage and importance of high-quality water and cost-effective milk production. 31:56
Dr. Lance Baumgard discussed the negative consequences of in utero heat stress and the calf becoming less feed efficient and less productive. 49:52
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Scott Sorrell (00:07):
Evening everyone. And welcome to the Real Science Exchange. The pubcast where leading scientists and industry professionals meet over a few drinks to discuss the latest ideas and trends in animal nutrition. Summer heat is at full strength. It was actually 90 degrees here at my house over the weekend, and that means heat stress for your animals. Tonight, we've brought together a powerhouse round table of experts in the field of heat stress management to talk through the physiology and mechanisms for effectively managing heat stress. Hi, I’m Scott Sorrell, one of your hosts at the Real Science Exchange tonight, we have a very special opportunity to sit at the pub table with three icons of heat stress management, Dr. Bob Collier from University of Idaho, Dr. Rosemarie Zimbelman from Dairy Nutrition Services, and Dr. Lance Baumgard from Iowa State University. Lance, you've joined us before at the real science lecture series, but this was everyone's first time at the exchange. So welcome to everyone and cheers! Dr. Baumgard, you’ve worked with both Dr. Collier and Dr. Zimbelman on some research projects. Any stories that you can share with us, and what are you drinking this afternoon?
Dr. Lance Baumgard (01:24)
I'm drinking Redbreast12. It’s an Irish whiskey. It’s a premium brand from Jameson and sons, and man is it some smooth whiskey dude. My wife is actually from Galway, so it's actually kind of fitting. Stories, man Scott, in the fear of mutual destruction I better keep my stories to a minimum. You can ruin me a lot faster than I can ruin them. It was a very productive time in Arizona, Bob hired me in 2001. There was a lot of productive people in Arizona back then. Marie ,and Matt van Bolluh, Rob Rhodes, others. It was a productive time to be there. Fun time.
Scott Sorrell (02:15)
Dr. Collier. First, what's in your glass tonight, and then tell us what led to your interest in studying heat, stress and dairy cattle
Dr. Bob Collier (02:23):
Well I’m drinking coffee, because I'm old. And I need that extra boost to keep me up late at night, but as far as my interest in heat stress, when I joined the faculty at the University of Florida in ‘75, that was... the position that I took was the environmental physiology position. And I had never really worked in the area of environmental physiology before- it was a new field to me, but Florida is very consistent in the summer, as far as a heat stress environment. I can't imagine a place with a tougher environment because of not, just the high temperature, but also consistently high relative humidity. And later in my career, when I was in Arizona you have higher air temperatures, but lower relative humidity, which actually gives you lots of options for cooling. And moving air and evaporating water into that air which you don't have nearly to that extent in Florida.
(02:26):
So I consider Florida a much harsher environment than Arizona, and I think the milk production per state kind of agrees with that. When you look at the average milk, you know, Florida versus Arizona. Whether, another comment I might just add is that through this whole last 50 years, what has really changed most dramatically is not so much the environment. It's the cow. The cow, because of a genetically selecting higher in our levels of production. The cow today is producing twice as much heat as a cow did in 1945 or in the, in the early 1950s, people often lose sight of that fact that worry about the environment. But if we, we changed our cows so much, and that is part of the reason why we have an increased need for cooling, regardless of where you are in the United States.
(03:33):
Summer heat loads now at the levels of production we're at you know, typically just about any place in this country, a cow's going to experience heat stress at some point during the summer. Which didn't always use to be the case. And it isn't, it isn't so much climate change that's done that. It’s what we've done all through the productivity of the cow, which increases its maintenance requirements in the way of handling, cooling, feeding, all the things that go along with supporting high milk production. We have to alter because of the external heat load issue that the cows face. They become more and more sensitive to heat stress, and more and more resistant to cold stress.
Scott Sorrell (05:27):
Excellent. And finally, Dr. Zimbleman, welcome to the exchange. You're bringing the practical aspect in tonight's conversation since you're working directly with dairy’s as a nutritionist and the owner of dairy nutrition services. What are you drinking tonight? And as a third generation dairy producer and second generation nutritionist, what changes you seeing around heat stress management at the farm level?
Dr. Rosemarie Zimbelman (05:52):
Well tonight or this morning, I should say because I'm still at work, I've managed to slip in Kalua into my coffee. So cheers to you all. You know back when I started my graduate studies with Matt van Bala and then Lance and Bob as well, and for my PhD. I'm born and raised in Arizona. All I know is heat stress. So for me, being on dairies very young and seeing the cows and always talking about what can we do to improve their comfort, and when the environment during the summer months was something that was really important to me. So I see technology advancing, I see different units that we've been able to bring to the table. Evaporative cooling methods that have improved over time. Some nutritional strategies that, thanks to people like Lance and Bob, we've been able to kind of dial in or try to improve for the cow as well. So I think those are some of the improvements that we've seen in the last 40 years. Scott Sorrell (06:51):
Excellent.
And last but not least Dr. Clay Zimmerman, my steady co-host Clay. Do you have anything cool in your glass tonight?
Dr. Clay Zimmerman (06:58):
I do. I have a, a watermelon hard cider here.
Scott Sorrell (07:04):
Nice. Yeah. Very summery. Yeah, I’d expect no less of you, man. That's awesome. Good.
Dr. Clay Zimmerman (07:11):
So Scott, what's in your glass tonight.
Scott Sorrell (07:14):
Oh, fancy you should ask. I was, was looking at the liquor shelves this last weekend and I found this it's called bastille. It's a French whiskey. I don't know much about it, but at the little note here says it's 94 points. So I'm going to assume that's pretty good. I've had it, having it, enjoy it. And it reminds me a little bit of an Irish whiskey really or maybe a little bit of a scotch kind of a flavor to it as well. It's certainly different than the U S bourbons here and I'm drinking it from this very special glass. My daughter she goes to The Ohio State University and she is in evolutionary biology. And so she got this for me for Christmas and I just got the glass because we did not get together due to COVID for Christmas time. So I was just able to see her the other day. So that was a special treat. Her name is Hannah by the way, Hannah Sorrell. So thank you, Hannah. So Bob let's, let's start with a basics. What is heat stress and how do we define it?
Dr. Bob Collier (08:21):
Well, first any stress generally will place pressure on the physiological system of the animal so that in order to meet that stress, the maintenance requirements of the animal will go up whether that's a shipping stress, or a let's say starvation as a stress, or the impact of heat or cold. In order to meet that added pressure, there's logical pressure on the body... the animals wants to divert resources in order to meet that stress. And those resources are added to what's called maintenance costs. So true stress always increases the maintenance cost of an animal. And typically, that energy, or protein, whatever that is needed to meet that maintenance cost comes out of production because that is now required for the survival of the animal. And so may production typically will drop them as a result of the stress because the animal has to divert those resources to meet the stress. Stresses are additive.
(09:46):
So if you have multiple stressors on a dairy, and typically there are. Crowding social stresses, you know, the stress of a disease, or just management related issues where animals aren't handled properly. And these all are additive and impact production. And that's why, if you look at the heritability of milk production, only 25% is related to the genetics of the animal. It's 75% of the differences between animals and between dairies and production is due to the environment, the cows are in. And so individual farms could vary dramatically, and the actual environment around the animals, the microenvironment, and how many stressors are in that environment. And therefore how much of its production ability goes just to maintenance in order for the animal to survive in that environment. So, if you, if you took a cow that's producing, let's say a world record holder around 75 to 70, 78,000 pounds of milk, now.
(11:05):
Now clone that animal and spread it, millions of copies across all the dairies in the United States. You would not get every cow producing that world record. You would get a bell-shaped curve. The actual median, the mean of that curve would be a little higher because of improved genetics of that animal. But because of the tremendous difference in environments, you'd get a bell-shaped curve in milk yield across, even though they're all copies of the same animal. So basically, heat stress is a stress. And because dairy cows, as I mentioned earlier, have in this country, have dramatically improved their milk production, our cows are very sensitive to heat stress, which requires..... So I don't, I don't know if I've kind of wandered a little bit on, on answering your question, but the bottom line is, is a major threat to productivity of dairy cows. And it's something every producer in the country does now have to spend some time addressing the impact of heat stress on their cows.
Dr. Lance Baumgard (12:27):
Hey, Bob I was three years old when you joined the faculty at the University of Florida. Can I, can I ask you a quick a question? Cause I think it has a lot of practical implications on the maintenance cost and you know, what Bob said is written about, you know, by, by the legends and bioenergetics, but what if, what if maintenance costs actually were not increased during heat stress, but were reduced. And then from Rosemarie's perspective, what, what type of implications would that have on ration balancing during each stress? Theoretically, what if they’re reduced?
Dr. Rosemarie Zimbelman (13:14):
I just don't see how that would happen, but maybe I'm wrong and maybe I'm just not viewing it from a smart enough, you know, Cornelian perspective. But I, I just on pharma, it's just one of those things that you automatically see, you know, you've got the energy dense diet that you've been feeding and then automatically he comes in and boom, you're down and what's changed, right. Just the environment. So I, I don't know how that survival mechanism hasn't happened, even when in humans, it kind of changes, right. You know, our basal levels of meeting our metabolic rates. And then all of a sudden we put ourselves in a different stressful environment. And that's what we see too. So sorry, Lance. I'm not that imaginative.
Dr. Bob Collier (13:54):
Well, I was going to say, I'm trying to think about a situation that would happen, but theoretically, if you, if you reduce maintenance costs that should allow the animal to spend more towards production.
Dr. Lance Baumgard (14:09):
Okay. But you remember part of maintenance costs is the energetic need to maintain a constant body temperature, right. To generate heat, to maintain a healthy body temp. And I'm always wondered you know, now when when an animal is in a hot environment, the burden to generate its own metabolic heat to maintain body temp has now kind of been removed. And I know we're going down a rabbit hole, maybe?
Dr. Rosemarie Zimbelman (14:38):
I guess another question I have, Lance's like, what is, what is the cost of having to keep your body warm, or the cow's body warm, and what is the cost of having to cool the body? Because I guess in my perspective, based on what we've seen, you know, with all the stuff that we've done, it, the data collections we've done at the University of Arizona, back in the day, you see so much more energy expenditure with panting, respiration rates, trying to dissipate that heat that I guess I just see those costs increasing or that, that cost increasing rather than, than not.
Dr. Lance Baumgard (15:10):
Yep. Yep. So there's certainly an increased, energetic costsof that working diaphragm. Right? But is that, is that offset by the reduction in metabolic heat produced by the other muscles of the body? I don't know. I'm just throwing out. I know this is kind of an out there concept, but I'm just, I was wondering, I don't think it costs much to sweat. I don't know how much ATP it costs to sweat.
Dr. Rosemarie Zimbelman (15:41):
Well, I think the problem with the cows is the type of sweat glands they have versus the type of sweat glands that horses have, right. Cows are inefficient sweaters. And in my, from what I've learned from geniuses that are on this call and more.
Dr. Bob Collier (15:57):
Cows, cows and horses are inefficient sweat glands. It's humans that have the eptrippial. Humans are pretty good sweaters, but the horse is the champion. Horses sweat life at twice the rate of the human.
Dr. Rosemarie Zimbelman (16:15):
So how do we make that happen in cows?
Dr. Bob Collier (16:21):
That's, that's the opportunity. If we could get cows to sweat like horses. We could dramatically improve their ability to have standing with thermal load.
Scott Sorrell (16:30):
How realistic is that? Right. We can do virtually anything now with gene splicing. Is that going to happen someday? Yeah.
Dr. Bob Collier (16:38):
I think it's realistic, but you know because it takes water and so does milk yield. So we, you have to wonder where, how much is going to impact milk yield to have high sweating rate cows, but we really don't know if we could sort that out without. In other words, get a high sweating rate cow without impacting the ability to produce milk. But interestingly, you know the mammary glands have modified sweat glands. So the, the process, once you once we get into the actual biology of it, it's going to be pretty fascinating.
Dr. Clay Zimmerman (17:25):
So Bob, what is different physiologically about these heat tolerant breeds.
Dr. Bob Collier (17:28):
Well if you look, traditionally, heat tolerant breeds grow slower. Also, if talking about beef animals, it tastes twice as long to get to maturity. If you talking about milk yield, I like to compare Pakistan with 33 million dairy animals, and they produce 1/10th of milk production of the United States with 9 million dairy animals. So they're chronically short of milk and chronically short of forage, you know. The truth is that, you know, the cows or in the dairy, that's really in the genetics. If you brought in high genetic capable animals, they still have to learn how to manage it. It's a evolving process when you do that in any country. China has gone through this, you know, they've got some really fantastic facilities, but have really had some major disasters when it comes to getting cows at those facilities to perform.
Scott Sorrell (18:40):
Rosemarie, let's kick it over to you for a second. What are your dairy and dairy farmers doing from a mechanical perspective to mitigate heat stress?
Dr. Rosemarie Zimbelman (18:49):
You know, I sit here and I listening to Bob and talking about, you know, we've, we've, we've seen the research, we've done what we can to alter the environment as much as possible. Maybe there's not much more we can do there as far as research shows and you know, nutritionally, there's only so many things that may or may not help depending on where you're at and what your herd looks like. I would eat, and I sit here and I think, you know, it's still back to basics for me. I still see a lot of overcrowding. I still see a lot of people who just want to milk more cows and want to milk what they need to milk. And I understand that from a survival and an economic standpoint, for sure. But I just wonder how much milk we're leaving on the table during heat stress and those types of things.
Dr. Rosemarie Zimbelman (19:31):
So I go back to the basics of what do we do to alter that diet in the summertime, in the heat stress moments that would be different. And, and what can we do, you know, to manage our herd better so that we don't have these issues? Where do we, if you can't afford cooling everywhere, it doesn't make sense for you to have cooling everywhere. Is there a place that you should implement cooling? You know in just one area or another, I think size of herd really makes a difference because you can do things maybe with less cows than you can with more cows, and then you can apply more with more cows than you can with less cows. So there's different things that I think can happen across herds. But I still think as a whole, as an industry, I think we still see a lot of, of management things that could be improved upon.
Scott Sorrell (20:16):
So you mentioned kind of dietary our, our nutritional strategies. What are some of those kinds of things that you implement?
Dr. Rosemarie Zimbelman (20:54):
Well, I think trying to, you know, in the summertime to decrease the amount of metabolic heat that we're creating, what the ration is, is something that we need to focus on as nutritionist to try to encourage our, our dairy producers to go towards that direction during the summer. I think, you know, we have products out there, you know yeast, direct fed microbials, buffers you know. Heat altering mechanisms like niacin. And then we also have you know, the fats. The fats have always played a huge part in, in helping us get a more energy dense diet during the summertime. So looking at those cost-effective things that work for your herds in whatever location you are and whatever size they are is also, you know, something that is detrimental to helping them get more comfortable.
Scott Sorrell (21:44):
Lance kind of maybe switching gears just a little bit. I know that you've done a lot of work with heat stress and leaky gut. Tell us what your learnings are there and, and how we can, how we can mitigate or treat that.
Dr. Lance Baumgard (22:06):
Yep, so we believe that almost, almost all of the negative consequences of heat stress emanate from the gut, right? Obviously you have a reduction in feed intake, which is a big portion of it about half, but there's this other 50%, that's difficult to identify where it's coming from, at least on milk yield. And so what I think happens is you have this redistribution of blood. You also have a psychological stress issue going on. And there's mass cells that reside inside the gut. And when they become activated by the stress hormone called, called corticotropin releasing factor, they release their contents and these proteases, TNF, alpha, histamine, et cetera, for some unknown reasons caused the gut tight junction proteins to be essentially pulled back into the cells that make em, and the gut becomes leaky. And this allows antigens...it allows entire pathogens to infiltrate the barrier of the system and the animal has an immune response. And ultimately the biological consequences of heat stress aren't very dissimilar to any other infection mastitis, metritis, et cetra.
(23:52):
The animals have an immune response. So yeah, I think dietary strategies that are targeting the barrier function of, of the GI tract will probably pay dividends. That's difficult, right? One third of the adult population has a barrier issue of their own bowel in humans, right? Irritable bowel syndrome, celiacs, Crohn's, et cetera, colitis. And so the human pharmaceutical companies have been chasing barrier function target molecules for a very long time. And essentially yeah, to be overly successful. Right. So not to be a Debbie downer, but I think there's a massive opportunity in targeting the gut during heat stress. Just not sure we have a magic bullet yet. There's certainly some things that we can help manage it, heavy metals, antioxidants, stuff like that.
Scott Sorrell (24:25):
Sounds like what we really need to do is just avoid it in the first place. Yeah. Prevent her from getting hot. Yep. Yep. So.
Dr. Rosemarie Zimbelman (24:05):
On that same token, you, Scott, you know, there's places where it's obviously very, very hot in the middle East that don't have a problem getting high producing cows, you know, 44, 45 kilos on 13,000 or 20,000 plus milking cows. So obviously it can be done, but what, what is the management strategies that are being done there, nutritional strategies? But again, I think it's back to the basics is just such an important thing to help those cows get, get it right.
Dr. Bob Collier (25:08):
Even with incredibly high afternoon temperatures in the summer Arizona has been ramped up there as far as the average production production per cow in the top three, typically, I don't know if they're there today, but when, when I was at Arizona, we were always in the top three, as far as production per cow. And that was due to high quality forages, which you get in dry environments. You, you know, it's really difficult to get 10% moisture in hay in Florida. And so you just don't, you don't get that quality of hay and then you, you can also cool your cows more effectively in Arizona that he can in Florida. So those two factors really helped the Arizona dairy industry, as far as improving production capital costs are going to be high because of the relative cooling equipment required in Arizona compared to Florida. But still if you look at the production costs, Arizona was producing milk at a lower cost than Florida is for sure, you know, on a, on a per hundred weight basis.
Scott Sorrell (26:27):
Yeah. So I'm wondering is that because it's a dry heat there? I mean, I was listening to Bobby was down there in Florida. He thinks that's the worst environment. Is that kind of the secret is, is environments where that, where it's a little dryer?
Dr. Rosemarie Zimbelman (26:41):
Well, Arizona's pretty dry, and I don't know that we achieved that level of milk production on that many cows as a state. But I will say that you know, I think it's obviously you've got a better chance without the humidity than, than with it. So yeah, I think that's part of the equation, but again, I go back to nutrition management control, of what you can control for these cows to get more comfortable.
Dr. Bob Collier (26:39):
So I just had to jump in here real quick. You know, if you've got a Saudi barn in Arizona with the air temperature at115 degrees and the Saudi barn, you know, has no sides to it, it's open, but if you have a corral cool coolers going in that barn, the air temperature in that barn will be 80 degrees because of the huge amount of water that could be evaporated. Bringing your temperature from 115 down to 80 is quite an accomplishment. Sure. If you're in Florida, you would never get the air temperature down to 80 degrees inside an open or a closed barn. You know, you just couldn't do it. The humidity is too high. Yeah.
Dr. Rosemarie Zimbelman (27:55):
And here in Arizona, we've got great herds with, I mean, great dairies all across the board, some have better cooling than others. Some are older than others. It's a huge capital investment. And again, you know, the West has always been a little, not, not so well paid as the East. So it's always been an issue of what can we do? What can we afford? And what does that look like? And what does that investment look like? So being creative about that is, and being economical with our dairy producers is always, always part of the challenge too. Scott,
Dr. Lance Baumgard (28:23):
Scott, you mentioned that humidity, right? So we just hosted the global dairy talks only about a month ago. And there was a fellow on there named Mike McCullough. Mccollee, sorry. And he talked about how heat stress is regionalizing where dairy cows are farmed in the United States. In large part because of this lack of cooling opportunities in the Southeast, he was really focusing on Georgia and South Carolina. And so in those States and how the dairy cows are moving from there, just because they're not able to cool them effectively because of the humidity. Yeah, he gave a really nice talk.
Scott Sorrell (28:32):
Does he anticipate that those moves will continue to take place? I'm going to assume there's going to be a certain base amount of animals to, to supply the fluid supply that's going to have to stay there. Right?
Dr. Lance Baumgard (29:09):
Well, that's what he was mentioning, right. Is that that's a huge population area of the country that obviously needs fluid milk, but the milks being shipped in from other regions, Texas panhandle. Yeah.
Dr. Bob Collier (28:45):
And in fact, you know, the milk in Florida for the producers are paid. The going price of milk in Wisconsin, plus the shipping costs from Wisconsin to Florida, the typical milk price is established in Florida. And that, because it's recognized that the heat stress adds additional cost of production. Yeah.
Scott Sorrell (29:51):
Good point. As we look at things like global warming, are we going to see, globally, different migrations of animals kind of pulling up in certain geographies versus others, but do you guys have any thoughts on that?
Dr. Bob Collier (30:07):
Well, I think it'll always go to the least cost position. I think that agriculture has to do that over time to survive. So dairy is no different than any other agbusiness. And so places that can produce milk the most efficiently with least cost and also least impact on the environment are going to be a successful long-term here.
Dr. Lance Baumgard (30:11):
This is complicated too, because of the human population is disproportionately expanding as well. And that human population growth is primarily occurring around the equator. Right. So animal agriculture will migrate to where the hungry mouths are. So then there's going to have this balancing act like Bob just got done talking about where, where can we cost-effectively produce food, but still be relatively close to where all the mouths are at. It'll be interesting to see what it looks like in 50 years. Yeah.
Dr. Clay Zimmerman (31:13):
What role will water availability play on that?
Dr. Bob Collier (31:18):
It's gonna, it’s gonna have a major impact of the water requirement. And it varies of course by by livestock, but certainly dairy cows are big consumers of water. And so high quality water is the other point is it's not just water, but it has to be high quality water to safely produce milk.
Scott Sorrell (31:46):
Yeah. Talk a little bit about water quality, Bob. We all know it needs to be pathogen free, but you talking about mineral content or the lack thereof as well?
Dr. Bob Collier (31:56):
Oh, right. Yeah. And cost, I mean, you can get high quality water, but what's the cost to get there, you know, in some places that it comes out of the ground as a high quality source of nutrition, but other places it takes extensive treatment to reduce the salinity. Which more and more is an issue at California in the West. And also bacteria contamination which might alter the healthfulness of the water. So clean, safe water supply is not a minor issue.
Dr. Rosemarie Zimbelman (32:41):
Now you've got pH as well. The hardness of the water, all those things you had, you gotta test and look out for because they're nightmares if you encounter them. Especially places where you can drill your own Wells and they're not actively managed areas, water areas, that's something. But I think that goes back to Lance's point about these dairies are gonna move where they can get close enough to feed people, but still have all those beneficial requirements in order to be cost-effective.
Scott Sorrell (32:40):
Let's talk a little bit about the future guys. Where are we headed? Let's let's put, look into the crystal ball and where are we going from? Maybe it's a equipment or mechanical perspective. What state-of-the-art and where are we going? Where are we going with genetics? I know we've talked a little bit about that. But are we going to start seeing cows with big brahma ears on so they can dissipate heat? You know Lance, why don't we start with you? Where do you think we're going? Where do we need to go?
Dr. Lance Baumgard (33:10):
Oh yeah. Bob has mentioned that already a few times you mentioned that our cooling capacity has been maximized and that's a little scary when you think about it, right. I'd like to hear Bob talk more about that. There's really no more advances to be made from an engineering perspective, you think Bob? Well,
Dr. Bob Collier (34:32):
We, you know, we have some opportunity in conductive cooling. In other words, cooling, the surface the cow are gonna lie on, we've done some initial work, but that's yet to be proven economically viable. You know, there has to be a capital investment there by research that kind of a approach. And that could be for both heating and cooling, which would be very advantageous in the North. Well, when you've got a sand bedding that freezes, it becomes as hard as concrete. So having a way to regulate the environment, the animals are lying on is one opportunity that is not tapped yet. But as far as the effectiveness of fans: we know fan sizes, we know wind speeds, we know the impact of relative humidity. And so those are pretty much maximized. And so where do we go from here?
(35:038):
Well, but I mentioned there's one and that's conductive cooling. But then you got to start looking at the cows. What, what can we do to help the cow become more thermal tolerant? Depending, or, you know, the industry's going to move. Interestingly, you know, a lot of people don't realize, but Idaho is now a third largest dairy state in the country. A lot of cows had moved in to Idaho. And what's that, Oh God, well, they've got clean water, lots of it. And a great low humidity for that high quality forage, but also it’s cooler in Idaho. So you don't have as much heat stress. So there's been a big pocket of where the last 10 years is that dramatic increases in count number. Which we might not have predicted 10 years ago. But when you look at all the reasons why it becomes obvious, especially the regulations that producers in California, looking at the water quality issues and water availability issues it's pretty attractive.
Dr. Lance Baumgard (36:05):
Bob, from a genetics perspective. And you know, that slick gene in Florida, that Pete Hanson's working on with, is there an opportunity for the slick gene to work better in an arid environment? I presume.
Dr. Bob Collier (36:):
So the problem with the slick gene is a it's the prolactin receptor, and a prolactin receptor is really important for milk production and also for reproduction. So the slick gene, if you look for homozygous animals, they're very few and far between. Heterozygous animals, where you've got one copy of the gene, appear to be the most effective as far as survival and, and having a better response to a hot environment, but we haven't yet proven that they can produce more milk. So the, in the long run, how would you, if it has to be a heterozygous animal, that takes a different reading approach. So there's still questions. So the slick gene is, is an opportunity, but it may be limited because of those issues. What we really want is that sweat gland in the dairy cow, that's more productive.
(37:22):
And like I said, if mammary glands are a modified sweat gland, and we we've got that modified sweat gland up to 73,000+ pounds of milk at a 305 daty lactation, I think we can get cows to, if we just doubled sweating, right. It would have a huge impact on, on the cows ability to withstand with thermal load. What's a lot, you know, it takes one calorie to raise a gram of water, one degree centigrade. That's a, that's the measurement for a calorie, but if you just evaporate that same amount of water, it takes 580 calories. So evaporating one gram of water gets rid of 580 calories just to evaporate. So yeah, definitely sweating rate would have a huge impact, which means going from about 300 grams per square meter to 600 grams per square meter of, of skin service.
(38:27):
But you know, horses could produce 2000 grams of water for two liters per hour per square centimeter. So the biology says it can be done. The question is you know what, it's going to take a program to really identify what regulates sweating rate? We developed ways to isolate sweat glands and to culture them. But on, before I left Arizona, but never really got into what regulates sweat gland function, we know what the receptors are. We don't know what regulates how sweat glands work in cattle. It's still a big unknown. So it's an opportunity.
Dr. Clay Zimmerman (39:20):
How much does night cooling impact recovery from heat stress?
Dr. Bob Collier (39:30):
Well, there's been, there've been studies done in Missouri that looked at that, and in all locations, and you, you can have some pretty dramatic impacts with nighttime cooling. Because I did some work in the early eighties in Florida and the, the dairy cow that's out in the environment in Florida. It's not till about four o'clock in the morning before she gets back to the normal temperature. So she's panting all night long to get a, and they had typically cows would go out in the open, get out from under their barns because of barns have hot metal roofs, so that they're allowed to then go out in the open to actually radiate to the sky. So the question, you know, how much was nighttime going off for quite a bit, but we that's one of the things that a lot of producers will do and here's, you know, saying, well, the sun's going down on turn off the cooler.
(40:45):
And so the cows aren’t cooled all night. Another thing you see, you know, where the cows are dying and you look at death rates, which go up dramatically. They're dying in sick barns because stresses are additive. And if you go to a sick barns, how many sick barns are cooling cows? Almost none. If you go to a dairy and look at their sick barn, they’d said, well, this cows not producing milk, you know, I can't afford to pay for cooling, but they don't think about the cost of losing that cow and how much that would be their bias. Cooling a sick barn is a major opportunity. You know, it's a management opportunity we really haven't fully explored. You've mentioned another nighttime cool. There's still, there's still some management opportunities. When I said we reached our maximum, that's as far as the engineering capabilities of cooling, we, you know, these laws of thermodynamics still, no budge. So pretty much what our limitations are there. There's still opportunities in the management area.
Dr. Lance Baumgard (42:10):
Thank you, Clay. To your, to your point, and to expand on what Bob was just mentioning, you know, the Arizona Valley and Clovis, New Mexico, the daytime highs are not very different, right? And but the, the investment put into cooling on those dairies is very different, in large part because of the nighttime cooling that Clovis has an advantage on. So if you get a chance to do some touring of dairies, take a look at the dairies in Clovis versus the Arizona Valley. And both of those daytime highs are not very different. The nighttime lows are very different.
Dr. Bob Collier (42:53):
And the wind speed is quite a bit higher.
Dr. Rosemarie Zimbelman (43:00):
You know, it's, it's, it's here in Arizona. We start preparing for our summer months in March and April. And as, as nutritionists, we're trying to encourage to turn on cooling sooner than later. This year, for example, we're, we're hitting 106 yesterday. By the end of the week, we'll be 115 degrees. And we're late, it's a late start. I don't know how that, what that means for the fall, if we're going to be hot during Thanksgiving, but we'll, we'll find out. But it's one of those things that, yeah, it just, just because you feel great outside, we're not 1400 pounds, thank God, So, so we don't know what that means. You know, we have, we hopefully have better sweating capacities than they do, and we have air conditioning and we've adapted to wherever we live a little bit better.
(43:47)
So those are things that I think people forget or don't understand, or don't see, and, and trying to save costs on things is, is sometimes something, I wonder if it doesn't hurt us the way, the way we think about that, because while it's important to save costs, you have animals that are biological animals, that it doesn't matter what it costs. They need what they need in order to produce and to stay healthy. And when we talk about, well, I'm not going to turn the fans on for a while because I can save some money on electricity. I have sometimes said, you know, are we in this industry to save money or to make milk and be productive, because that's the offset that you have to look at and then investment of what we're doing for these animals
Dr. Clay Zimmerman (44:33):
Regarding calves. I mean, so we're well aware of the, the in utero impacts of heat stress on the, on that calf in utero. What about, what about heat stress in calves once they're born? What, what do we know about that and the impact? And what can we do once these calves are born?
Dr. Bob Collier (44:59):
Yeah, there's a, there's a big relationship between body mass and rate of heat exchange. So calves are going to heat faster, and they're also gonna criminal faster. So the, it is important to pay attention to what is happening to calves. They're, they're going to be more thermal tolerant because of their smaller volume mass and their lower heat productionn. Bu,t it's still it's still possible to reduce their growth rate and increase because of these stresses in the first 30 days if the animals are being heat stressed. Not many producers, actually evalutate their calved for heat stress, but, you know, it's a similar situation. You can, you don't necessarily have to take rectal temperatures. You can look at respiration rate and get a skin surface temperature and get a pretty good idea of whether the animal needs more cooling. So it's an opportunity to improve productivity at the calf level.
Dr. Rosemarie Zimbelman (46:25):
Isn't there a lot of research ,too coming out about the dam being pregnant with the baby and not being cooled and going under heat stress. And then that dam not being able to progress fast enough or effecting milk yield down the road?
Dr. Bob Collier (46:42):
Offspring have production too, not just a dam.
Dr. Rosemarie Zimbelman (46:46):
Well, that's what I'm saying. The calf ends up being born and having those repercussions from the mom being stressed, the dam being stressed with heat stress, is my understanding.
Dr. Bob Collier (46:54):
There's reduced passive transfer because of stress and the calf, which sets it up for a higher death rate, especially if it's hot, it's going to seek environments that aren't good, which are muddy pathogen laden environments that can lead to respiratory or digestive tract disease, which are the two big killers for calves.
Dr. Rosemarie Zimbelman (47:23):
And I don't know what the management percentage would be, but I don't know many people who effectively put cooling in their dry cows and close-ups because of costs because of availability, whatever that is. But you know, whether it's just fans or fans with misters or corral cools, or?
Dr. Bob Collier (47:43):
It is because the producers don't realize the value. What I like to say, the animals are basically trapped in the environment you create. They don't have the ability to go turn the gate and walk away. They're trapped in that environment. So it's the knowledge of the producer,it's us, recognizing what stresses are around the cow and trying to remove those as much as possible. If you get really high producing herds, that's basically what the manager is doing... is reducing all the stressors around animals because every time he reduces stress, production goes up. We used to have this paradox about BST. Is it BST is a stress on dairy animals. Well, milk yield cannot go up if the animal is being stressed. So it's a paradox to say that high-producing cows are being stressed. They're not being stressed. They're the healthiest cows in the herd. They're also the cows that are eating the best and they're, they're in the best environment. So we have to move away from the idea that high production itself is a major stressor. It's, it's, it's the management of the animals that is the major factor.
Dr. Clay Zimmerman (49:11):
So Lance, these calves that are experiencing heat stress, or are they are they experiencing leaky gut?
Dr. Lance Baumgard (49:22):
Yes, yep. And then of course you have the stress of weaning in the top. And like Bob already mentioned the stack stressor concept. Right. and I, I don't think it's a coincidence then that you know, like I said, the biological consequences of heat stress are so similar amongst species: pigs, chickens, calves, dairy cows. I don't think that's a coincidence- it's emanating from the gut. And what rosemarie just mentioned a few minutes ago, the negative consequences of in utero heat stress linger for a long time in the milk yield in the lactating dairy cows, Shelly roads, his group showed that nicely, that also occurs in pigs. We've demonstrated that multiple times now, where piglets coming from a heat stress sow grow slower, they become fatter. They're less feed efficient. Right? So our understanding of this in utero heat, stress affecting future productivity, I think Denis Armstrong did a lot of that stuff in Saudi Arabia, looking at future reproduction and future. Now, it's, it's a huge opportunity for us.
Dr. Rosemarie Zimbelman (50:47):
Scott, to your comment about the future. I wanted to just add that there's I don't, I can't remember the exact number, but there's hundreds and hundreds of patents for dairy and technology that are on, on the up and coming. And I think that's going to be something huge for our industry, if there's enough investment and enough startup there, right. To get that going. But I think as, as Bob said, you know, the mechanical part of engineering and, and what's available as, as things become less cost effective, or I guess more cost-effective with the improvement of technology. Right. I remember when TVs were several thousand dollars. Now you can get one for a couple of hundred, right. So I think as that evolves and things become less expensive in the technology world, that's only leaving more room to be more cost-effective on the dairy with more technology. And I think the management technology that's out there to be able to improve your herd is also something that, that the future holds for being able to manage these herds better and do better management. But I think it's just a lot of that. What does the research say about heat stress? What does the research say about how we should be managing cows? And not just focusing on, on necessarily what we want as humans, but what the cows need. Yeah.
Scott Sorrell (52:01):
Well said, and with that, I don't know if, yeah, go ahead, Bob.
Dr. Bob Collier (52:06):
That's it, precision farming is definitely going to be applied to dairy. And so remote sets of animals further formal status. Can we tie right into cooling systems that operate based on the animals as a thermometer rather than using a thermometer on the farm.
Scott Sorrell (52:30):
Oh, interesting concept. Yeah. I was just gonna say, I heard him call last call and I need another drink, so we'll get another round for everybody before they, they shut it down totally. But that means it's kind of to wrap it up here and kind of wrap up questions. I'd like to leave each of you. And we actually kind of started answering it, but is, is what's next? Or what needs to be next? And then maybe a take home message for nutritionists and dairy farmers and whoever might be listening in. And why don't I, anybody want to raise their hand, Lance? Would you like to go first?
Dr. Lance Baumgard (53:08):
Sure. Well, I am biased of course, but I think that the gut is the big, is where it's at. So identifying target molecules from the feed industry's perspective, I think we'll have a, will pay big dividends. But at the end of the day, from a producer's perspective, right, modifying the environment still remains probably the biggest return on investment that they have. And that's where I'll leave it.
Dr. Rosemarie Zimbelman (53:36):
I think Lance hit it on the head with his, his gut. I mean, look at the, the humans and what we're finding out about gut and how much it affects us and how that creates, you know, our health. And so I think that's definitely an important thing that we need to understand further, which Lance has done a great job of, of doing for us. I agree that, you know, we need to give them the best environment, but again, I go back to the basics of management and managing for the cows and not for, well, what we think is always best or what we feel is always best because the cow is a cow is the cow.
Scott Sorrell (54:09):
Good point. And Bob will give you the final word.
Dr. Bob Collier (54:13):
Oh, sure. I think in addition to what both Lance and Rosemarie have talked about is the sustainability aspect has got to be tied into it because of the net zero approach that the dairy industry is taking, where it's in everything now we're going to dohas to be viewed in that context. How's it going to impact the carbon footprint. And so whatever technologies we do decide to use, we'll also have to have an impact on net zero, regardless of, you know, whether there's cool, feeding, whatever. You know, there, there is the question whether methanogens are even needed in the rumen gut. Or whether they're just taking advantage of available excess hydrogen in that rumen. And so I think we've got to find it out, but there are some approaches that looking at wiping out that, as one example of what might be coming down. Hmm.
Scott Sorrell (54:38):
Well said, great way to wrap it up. Rosemarie, Bob, Lance, thank you so much for joining us tonight. We keep learning more and more about the lifelong impacts of heat stress can have on dairy cattle. So I look forward to bringing you guys back together, once again, here at the exchange for an update. And also want to thank our loyal listeners for stopping by at the exchange to share some time with us. If you like, what you heard, please remember to drop us a five rating on your way out, and don't forget tp request, your Real Science Exchange T-Shirt. All you need to do is like, or subscribe to the Real Science Exchange on your favorite podcast platform or YouTube, and send us a screenshot along with your address and shirt size to anh.marketing@balchem.com. Our real science lecture series of webinars continues the ruminant focus topics on the first Tuesday of every month, visit balchemanh.com/realscience to see upcoming events and past topics. We hope to see you next time here to Real Science Exchange, where it's always happy hour and you're always among friends. Stay cool!