This episode was recorded in Fort Wayne, Indiana, during the 2025 Tri-State Dairy Conference.
This episode was recorded in Fort Wayne, Indiana, during the 2025 Tri-State Dairy Conference.
Dr. Laporta gives an overview of her presentation, focusing on the impact of heat stress during the dry period on the cow, her daughters and her granddaughters. She covers heat stress impacts on mammary gland involution, as well as fetal programming effects on the daughter and granddaughter. (3:37)
Daughters of heat-stressed cows have fewer sweat glands located deeper in the skin, thicker skin and more sebaceous glands. This was observed at birth, weaning and puberty. They sweat more than heifers who weren’t heat stressed in utero, but have higher rectal temperatures during the preweaning phase. Dr. Laporta hypothesizes that if those calves were exposed to additional stress, they would be more susceptible to illness because of the higher core temperature. (6:34)
The panel discusses heat stress impacts on male fetuses and the potential for epigenetic changes to be transmitted through semen. Dr. Gerloff asks about differences in the impacts of heat stress on first-calf heifers compared to older cows. Dr. Laporta describes the survival rates of heifers who were heat-stressed in utero. Heifers are lost from the herd even before first calving, with more following in first and second lactation. (11:00)
Dr. Laporta outlines the differences between heat-stressed and cooled treatments in her experiments. They measure respiration rates and rectal temperatures to assess the physiological impacts of heat stress in the cows. Scott asks how long the heat stress period needs to be in order to observe negative effects. Dr. Gerloff asks about calf mortality rates between the two groups. Dr. Laporta estimates a 12% death loss in the heat stress groups, who seem to be more susceptible to the usual calf illnesses. It appears that gut closure might occur earlier in heat-stressed calves - maybe even before birth, which does not bode well for their immune systems. (16:49)
Dr. Laporta details how heat stress impacts mammary gland involution. Early in the dry period, you want a spike in cell death to build new cells for the next lactation. In heat-stressed cows, the spike in cell death early in the dry period is diminished, not allowing those cells to die. This results in less proliferation of the mammary gland, and the cow starts her next lactation with older cells that weren’t renewed in full. Thus, producing less milk. Dr. Gerloff shares some of his experiences with heat stress in his area of Illinois. (22:17)
Heat stress has negative impacts on other organs as well. Heifers who experienced heat stress in utero are born with larger adrenal glands with altered microstructure. Dr. Laporta describes some of the DNA methylation that has been observed in these heifers. The panel discusses whether the response would be similar for other types of stressors, like cold stress or social stress. (26:19)
What can we do to mitigate these impacts? Cooling dry cows so they can thermoregulate during gestation is critical. Altering diets to account for heat stress is also an important strategy. Unfortunately, there is no magic bullet to “fix” cows who were exposed to heat stress in utero, but these negative implications can be prevented. Dr. Laporta has also focused on what she calls perinatal programming - after the calf is born, what can we do? She has been working to develop cooling mechanisms for calves and is interested in further investigating early life mammary development. (33:41)
When a dry cow experiences heat stress, she has fewer and smaller alveoli. Daughters of those cows have smaller udders with altered tissue growth. Granddaughters of those cows have fewer estrogen receptors in their udders and negative impacts on mammary proliferation. (44:30)
Panelists share their take-home thoughts. (47:52)
Scott invites the audience to Bourbon and Brainiacs at ADSA in Louisville - a bourbon tasting with all your favorite professors! Sign up here: https://balchem.com/anh/bourbon/ (54:31)
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Scott Sorrell (00:09):
Good evening everyone, and welcome to the Real Science Exchange, the pubcast we're leading scientists and industry professionals meet over a few drinks to discuss the latest diet and trends in animal nutrition. We've got a good one teed up for you today. We're at the Tri-state nutrition conference here in Fort Wayne, Indiana, and we're gonna be discussing a presentation that's gonna take place here later this morning called The Impacts of Heat Stress on the Dry Cow and her Fetus. And that's gonna be presented by Dr. Humana Laporta from University of Wisconsin. Humana, welcome. This is kind of your, I think it's your third time to the pub. Yes. Welcome back. Before we get started, I'd like you just kind of, for those out there that may not know you just kind of give us a background about yourself, your pedigree, that kind of thing. Sure.
Dr. Jimena Laporta (00:53):
Well, first of all, thank you for having me. I like you said, I'm a associate professor at the University of Wisconsin. I'm originally from Ottawa in South America, came to the US in 2010 and never left. I did my PhD at the University of Wisconsin as well, and then started my career at the University of Florida, and then came back to the Dairy Land in 2020 back
Scott Sorrell (01:20):
To Wisconsin.
Dr. Jimena Laporta (01:21):
Yeah, I'm still there.
Scott Sorrell (01:22):
Good for you.
Clay Zimmerman (01:23):
Yeah. The winters were too brutal in Florida.
Dr. Jimena Laporta (01:25):
Get back. Yeah. Too humid. Too humid. I, yeah. Yeah. I needed some of the cold weather.
Scott Sorrell (01:29):
Good. Dr. Summer is in the co-pilot seat. Good morning Clay. Good to see you again. Yep. Good morning. Yeah. Any words of wisdom for us this morning?
Clay Zimmerman (01:40):
No, but looking forward to this
Scott Sorrell (01:41):
Conversation. Yeah. So am I. So we've got a color commentator today Dr. Brian Ger off Welcome. We recruited him last night at the baseball game, and glad to have you join us today. Well, thank you. So welcome. Why don't you tell us a little about yourself, Brian?
Dr. Brian Gerloff (01:56):
I, well, I live in a town called Woodstock, Illinois. If you've ever seen the movie Groundhog Day, you've seen my town.
Dr. Brian Gerloff (02:04):
And I grew up on a small dairy farm, went to Michigan State to veterinary school, worked several years in Ohio and decided as a practicing dairy veterinarian. I didn't know enough nutrition, so I went back and got my PhD in nutrition and then decided as a college person I needed to get back to practice and moved to my home area and started a dairy practice in Northern Illinois where I worked 25 years. And then about a dozen years ago, I went to work for Renaissance Nutrition as a full-time nutrition consultant. So that's been my story, and I'm sticking to it. Yeah.
Scott Sorrell (02:45):
Good. Listen, we're, we're glad to have you here this morning. It was interesting to find out that you and I just kinda missed each other paths there in Ohio. I think you were just ahead of me, but yes, looking forward to the conversation today. And we've got Laura NIUs is going to be the other, other co-host. You need the two co-hosts today, just. So Laura, tell us a little bit about yourself.
Dr. Laura Niehus (03:07):
Yeah thanks Scott. Like you said, I'm Laura NIUs and I am the technical services specialist for Balchem. So I'm recently started with balchem a couple months ago, and I'm covering the East coast and really enjoying it.
Scott Sorrell (03:21):
Good, good. Glad to have you, by the way. You're doing a great job and so appreciate it having you on a few podcasts here. Dr. Laporta, why don't you start off just kind of giving us some background about the presentation you're gonna give today. We'll use that as a base of our discussion.
Dr. Jimena Laporta (03:37):
Yes. So today's presentation is gonna focus mostly on the impact of gestation, so that dry cow on herself and her progeny, so the F ones and F twos. So the daughters and the granddaughters of those cows. So in this particular presentation, I will focus a little bit more on what happens to the cow herself in her mam gland as she undergoes the dry period evolution, redevelopment of that gland, which sometimes we forget that that's a very important period for the cow. Right? So what happens under heat stress? I'm gonna show a little bit of that. And then kind of moving on to the effects of fetal programming on both the, I, as I said, the daughter and the granddaughter that are gestating in utero, and the impact on that fetal ovary, that it's going to have effects on the second generation of granddaughters.
Dr. Jimena Laporta (04:31):
So that generation, we often don't think about when we think about lactate dry cows. So I wanna focus a little bit on that. 'cause we see effects down the road four or five years later in those they produce less milk, and we're now starting to see also impacts in their glands. So we were able to get some phenotypic data on them, and we see that their glands are smaller and less proliferative. So seeing that trend of impacts in the gland in the cow, the daughter and the granddaughter. So that's exciting for me, not so much for them. Yeah.
Scott Sorrell (05:06):
Yeah. No, that is exciting. So the, the one thing kind of struck me as you're, you're, you're laying that out, is that you're talking about the daughter, granddaughter. What about even future generations? Any hypothesis there is? How far out can epigenetics impact the lineage?
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Dr. Jimena Laporta (06:34):
Well, you're getting ahead of the game. Sorry. Because we are actually, we were able last year to collect some data from the F threes, so the daughters of the F twos. So in 2020 when I moved from Florida to Wisconsin, I, I brought 40 heifers with me. Those were the F1, the first generation, and we generated the F two and then the F three. And now we have some data on the F three. I'm not gonna say anything about them. I'm gonna build some suspense. Yeah. but yeah, we're, we're seeing some effects. The data we have so far, I'm gonna give you a hint. It's in their skin, their sweat glands are different, and we have seen that as well in the F ones and F two. So we collected some mammary data, so we're gonna go that path. But, you know, that's, we started this project with Jeff in Florida in 2018. Yeah. So,
Scott Sorrell (07:32):
So what led you to
Dr. Jimena Laporta (07:33):
it's been a while
Scott Sorrell (07:34):
To look at the skin?
Dr. Jimena Laporta (07:36):
Well, the skin is something that was new to me was something that, excuse me, one of my grad students got interest in. Yeah. While we were in Florida. It's one of the adaptations that the in utero heifer will have, right? She, excuse me, she's exposed to high temperatures in utero. So one of the things she will do is, all right, I need to adapt, right? I need to change. What am I gonna do? So she stopped, not stopped growing, but she reduces her growth rate. And one of the other things that she adapt it is her skin. Okay. and when I say skin, it's a lot more than that. I'm talking about sweat glands, specifically the thickness of the epidermis. So there's a lot of things and something that we observed that was sort of surprising, or at least I didn't know much about the sebaceous glands. Yeah. And those are very different. And those, even at after one year of age, we still see differences. So still don't know what they do.
Scott Sorrell (08:36):
And what are , do they sweat more or less?
Dr. Jimena Laporta (08:38):
Well, it depends on when you look at it. I'm trying to remember quickly my, the, the results that actually my student is writing her thesis now. So I've seen this recently. So basically the heat stress I'm talking about the F1. So the daughters that were exposed to that in utero environment, so they have less sweat glands.
Clay Zimmerman (09:01):
Okay.
Dr. Jimena Laporta (09:02):
If they are heat stress, and those sweat glands are deeper into the skin, so they kind of get farther away from the surface and the skin is thicker. So those are two things that we see in the, in the daughters. Yeah. And they have more sebaceous clans, presumably, for trying to hide. I don't know. So we're trying to figure that out. And then we also see, we did it at birth, at weaning, at puberty, and we see that in that F1 consistent effect, even one year after. So that effect in the sweatland seems to be a little permanent. So what I don't know, and I wish I would have done
Clay Zimmerman (10:38):
Does the higher temp, does that persist or just during the pre-weaning?
Dr. Jimena Laporta (10:42):
We only did during the pre-weaning phase, yes. Then we follow them. But we did more intense work in those first two months of life. Yeah. But we, we tried to do some other things that didn't work, so I'm not gonna talk about those.
Clay Zimmerman (10:57):
The taser.
Dr. Brian Gerloff (11:00):
I have a question. So you looked at these changes epigenetically in a female offspring. Yep. Have you looked in male offspring as the potential to have different genetics from males that were
Dr. Jimena Laporta (11:16):
Heat stripped? Yeah. I, I personally have not, but I know that other groups are, are doing that, and the potential to transmitted epigenetic changes through the semen. I, I personally have not, but heat stress definitely has an impact there. I think there's, there's a lot of work in sheep showing that there are also transgenerational effects of heat, stress of, or, or nutrition through the male line.
Clay Zimmerman (11:41):
And those are beneficial effects.
Dr. Jimena Laporta (11:43):
I don't know. Okay. Yeah, I don't remember. It depends on, I I mean, heat stress, I don't think so. I think nutrition, the, the ones with nutrition that I have seen are beneficial. Yeah. Okay. But I don't think there's anything good about heat stress,
Clay Zimmerman (11:57):
Actually, no. I, I, yeah.
Dr. Brian Gerloff (11:59):
One more question. Is there a difference between the effects in Premiparous versus maltis animals?
Dr. Jimena Laporta (12:08):
Yes. That's a great question. And, and, and we had that same question. We did a project where we look at the primiparous heifers heat stress, although they don't have a dry period, so our focus was the dry period, but the primiparous heifers don't have, right. The new lips heifers, first calf heifers but their ma glands are growing exponentially during that day gestation. And that's something that we often forget. But because I'm a Maori physiologist, I, I look at those things, right? So we, we did a project where we heat stress or cool heifers that were on pasture. We brought them inside. I, I'm not showing that today. But we see that the effects that we see MultiPro cows are there, they're smaller in magnitude, right? They, those heifers are still growing and things like that. So we don't see those bigger difference in, in rectal temperature. But we do see differences in, in skin temperature, in, in rectal temperature and sweating rates in those premiparous no leper heifers and lower production in their first lactation. We didn't dive deep into the gland itself to explain those changes. But 99% that is through reduced proliferation and growth of the MA gland in that late gestation. Okay. We also see differences in the offspring as well.
Clay Zimmerman (13:34):
So in the, am I right in the, in the F ones, as lactation number increases, that difference in milk yield loss increases, right?
Dr. Jimena Laporta (13:46):
Yeah, it does. Yeah. It's I think the third lactation is the one where you see the most difference. I don't know if that's, you know, due to we are losing a lot of animals, right? But I think that that third lactation is really when they, they need to express the potential, right? And when we wanna see the, the biggest difference in, in, in our cows or higher production, but it's when the heat stress do the worst and I think it's like six kilos per day, less. So that's pretty significant. But we also have to remember that the survival rate of these heifers goes down, right? I'm gonna show that today. But we, we start losing them very early, even before the first Calvin. So we're losing heifers early on. We're losing heifers in their first second lactation. So by then we have a lot less.
Clay Zimmerman (14:38):
Are they, are they harder to get pregnant? Nala, Paris?
Dr. Jimena Laporta (14:43):
Yeah. We always look at that. But even though for the research that we do, our numbers are pretty good. We still are not there yet. I think we have done that. We report that, but it's taking it with a grain of salt. We still see some they need more breedings and things like that. But I think that there, there are a couple of studies that Jeff did in Florida with data, more data from California and Florida, that they are able to see that when they look at summer versus winter type with a larger, larger, yes. Like looking more at health and things like that. 'cause You need numbers. Right. So,
Dr. Laura Niehus (15:24):
So I'm gonna quick question for you. Just kind of compounding off of that. Do you notice, or have you made a large attempt to make sure that those heifers that came from heat stress dams aren't heat stressed again? Or do you have any compounding effect of multiple times being heat stress like it typically would with summer?
Dr. Jimena Laporta (15:47):
That's a great question. So all of this projects were done in the summer of, in Florida summer, hot, humid, and they are born within a month, you know and that prew period is typically September, October, November. So they are kind of okay for Florida weather at least. And then they, as soon as they are born, the cows from heat stress or cool cows, they are all together. So they might have gone through, I get this question a lot. They might have gone through future heat stress events, but they all go together right. As a group, as a cohort. So, yes. They live in Florida, so there's no escape from that. Right. So yes, I think they have gone through some events, but altogether,
Scott Sorrell (16:37):
So for the purpose of this, of the trial, how did you define heat stress? Right? So you're in Florida, we know it's hot down there, but how does that relate to, let's say, Illinois, Wisconsin? Can you talk a little bit about that?
Dr. Jimena Laporta (16:49):
So typically we define heat stress based on the temperature humidity index. Where in Florida it doesn't get, temperature-wise, it doesn't get that high. It's the humidity that it's a killer, right? And we typically look at THI greater than 68 or 72 typically for, for cows. But in, in our projects, what we measure regularly is the rectal temperature. We do that a few times several times a day. We do respiration rates. So we confirm that they are under heat stress physiologically, and also through the environment that that's a given. They are going to be, it's gonna be hot. But we, the, the heat stress group don't have funds and soakers, so they are in a barn without any cooling. And the other group has fans and soakers. Yeah. So that brings down that temperature, rectal temperature, respiration rate. So that cow is more on under thermo neutral conditions, although she's in the same environment, but we're helping her to thermoregulate. And so that fetus that it's inside her, it's gonna be quote unquote cool or just stated under thermo neutral conditions to be more precise. But yeah, that's how, how we define, we look at the environment, we look at the physiology of the cow
Scott Sorrell (18:12):
As well. And then how many days under heat stress does it take to get the kind of impact that you're talking about?
Dr. Jimena Laporta (18:17):
Yes. So typically a dry period is six to eight weeks, depending on what you do in, in your farms. But in Florida it was actually a little shorter, 49 days, seven weeks. So that's what we, when we did the, the heifer study, we ensured that they were under heat stress for 60 days because we wanted to target those last two months of gestation. But in the multimer cows is typically 40, 49, 50 days.
Scott Sorrell (18:47):
Do you have a feel for how many days it's gonna take to cause the effect, you know, five 10
Dr. Jimena Laporta (18:55):
In the fetus or in the,
Scott Sorrell (18:56):
In, in, in, in the dry cows, if they're so, you know, of their Yeah. Dry period. Let's say they're only under heat stress for 10 days, right? Right. Are you gonna get the negative impact
Dr. Jimena Laporta (19:06):
For the entire next lactation? I'm not sure. Yeah. So we have to think when we do this, let's say six, seven weeks heat heat stress, dry period, that has effects. And I'm gonna show a graph for 40 weeks in the next lactation. So a seven week event has carried over effects 40 weeks, the, in the next lactation. Now we did one study, kind of get into that question. What if we cool them only during the closeup for three weeks? Will that be enough? Or what if we cool them early on in, in the dry period? Will that be enough? And the answer to that is no. So we, we need to cool them through the, in Florida, through the whole time to see those benefits in the next lactation. We didn't follow the calves from those that we swap, but but yes, I think, I think three weeks is, is going to impact the physiology of the cow, but cooling, I'm saying in this case, but it's, it's probably not enough. Yeah.
Dr. Brian Gerloff (20:17):
What was the difference in mortality rate on the cabs? Between the heat stressed and unstressed?
Dr. Jimena Laporta (20:24):
Trying to think about the, the survival graph. I think we see 12% in, in that first couple months in the prew phase.
Scott Sorrell (20:33):
And what was the cause of most of those losses?
Dr. Jimena Laporta (20:37):
The typical things, but so like, I'm trying to remember the last one of the last study we did there they were just very lethargic, so they didn't want to eat. They're, they're, they're dry matter is depressed and they just don't do well. Yeah, they're smaller and they have a harder time to absorb immunoglobulin. So there's a sort of things that happen to them that leads to that phenotype. And yeah. So they, they are off to a terrible start. Yeah.
Clay Zimmerman (21:10):
Does, does gut closure start earlier in those calves?
Dr. Jimena Laporta (21:13):
That's a, that's a Jeff theory. Yes. we have done some projects and we're finishing up one right now. We euthanize some heifers, and we look at the gut, different portions of the gut to dive deeper into that. We have some indication that the gut closure is happening a little bit earlier before they are born. And so when they hit the ground, we give them colostrum, they are like, eh, you know, and so there's a lot of implications to that, right? In, in terms of their acquire acquisition of immune function and things like that later on. And they get more sick more often, and they end up leaving the hurt. But in the gut, we see that they have more cells dying, and we know that heat stress in any tissue, it's, it's triggering cell death. So they are seven weeks in that harsh environment, and that's triggering their, their gut to, that's what we looked at, mammary gland, gut skin, you know, but pretty much every other tissue, it's impacted.
Clay Zimmerman (22:17):
So we don't, I don't think we think much about mammary gland involution. I'm curious, so what are the differences that you're seeing in these dams?
Dr. Jimena Laporta (22:26):
So the it, during the dry period, you have the early stages that are, we call involution. So that's when you want cell deaths to happen. So you wanna spike in cell death through apoptosis or, or other ways of cell death. So you want that to happen early on. And then as the cow approaches lactation, and with the hormones of pregnancy and all of that, the mammary gland is gonna proliferate. It's gonna renew those cells, and she's gonna produce milk in the next lactation. What heat stress does in that dry cow is not allowing those cells to die, actually. So the, the, the peak that we want in cell death is diminished early on, and that therefore, it does not allow the gland to proliferate as much. So the glands starts her next lactation with older cells, she couldn't renew them in full, and so she produced less milk. That's kind of what we agree on.
Clay Zimmerman (23:26):
So to simplify it, I'm gonna put it in simple terms here. You wanna tear it down and build it back better?
Dr. Jimena Laporta (23:31):
Exactly. Yes. Yes. And that's why the dry period is so important. And every time I see, let's eliminate the dry period. No, please don't. Because that's what we, why we offer a dry period so that the mammary gland that has been been making milk for 10 months or more can rebuild, yes. Can get rid of the old cells, bring in new ones. And
Dr. Laura Niehus (23:53):
Now, Jimena, have you ever looked at heat stress during lactation, having any of those same effects? I mean, I know that cows are typically cooled, but if we're thinking maybe in the late pregnant pen, what if those cows aren't cooled? Have you looked at that at all?
Dr. Jimena Laporta (24:12):
I have not. But Chateau, good friend and collaborator too he has done some of that work and some work from Virginia Tech as well, have heat stress danal sorry, heat stress work, looking at the mammary gland specifically. And yeah, you see the same effects. Nothing good, obviously. So more cell death, less proliferation, and just that immune response is diminished as well. So we also need that for, for that cell renewal and, and things like that. And as the, especially in late lactation, those cows are starting slowly but surely to decline, right? So those processes start early on. When we dry them off, we stimulate them to happen more quickly, but they, they're already going down, right? So, yes, again, nothing good about heat stress.
Scott Sorrell (25:04):
Yeah. Dr. Ger, I'm kind of curious in your area where you work, do you see a lot of heat stress with a lot of your herds and you do some interventions to try to cool the calf?
Dr. Brian Gerloff (25:15):
We certainly do in Northern Illinois, not as bad as Southern Illinois, but yeah, we certainly have heat stress for periods of time on one thing that's perhaps fortunate is we often get a window of bad heat stress, and then it cools off. So it isn't as continuous, I think, as some, as Florida, for example. But yeah, no, I would say in my client base, we probably only about half of them really worry about mitigating heat stress and dry cows in the lactating cows. Pretty much almost everyone does, but dry cows not as much. Mm-Hmm
Scott Sorrell (26:07):
So I had a question for you. You, you were talking before about the impact on skin sweating, memory gland. What about other organs? Right. do we, do we know? Have we looked?
Dr. Jimena Laporta (26:19):
Yes. we're very curious. So we look at a bunch of things. So one of the, the tissues that we have looked at also is the adrenal gland. The adrenal gland is important because it's where cortisol is secreted. And what we see is the heifers that are born to heat stress dry cows are born with larger adrenal glands, actually because they're working hard, right? Even before they're born. So what, what we see is in large adrenal glands with the microstructure of that tissue all altered. And so presumably there's gonna be you know, the adrenal gland greets a bunch of other things. So, and so the physiology is going to be impacted of those things as well. So we look at the microstructure and we see that the layers are all messed up. And so it's, it's a holistic effect. It's not one tissue. It's, it's all the tissues. Trying to think what, what else? Immune, immune tissues are also immune organs makes sense are impacted as well. Yeah. So a lot
Dr. Laura Niehus (27:30):
Of things come. What spurred you to look at the adrenal gland? Why did you first think, oh, we should, we should take a look at this and see if it's different.
Dr. Jimena Laporta (27:38):
Just thinking about that cortisol secretion and how that in utero hypothermia might do to the adrenal gang. We did RNA sequencing. We have a bunch of pathways that are impacted and things like that, that are very interesting to look at. But what I'm, I'm impressed is about the, the effect in, in the size of the organs and the morphology. The microstructure, I'm really, I really like to do, to do histology to see the, the microstructure of the tissue and what the cells are. And that's what strike me the most. They are, they're larger and their layers are all impacted in, in the thickness and the cells that they have. So so not only the, the, the things that they can express and secrete, but also the morphology of the, of the tissues, and obviously the mammary gland, it's one of the ones I look the most. If
Dr. Brian Gerloff (28:32):
The heat stress is producing epigenetic changes in the fetus, is that animal more tolerant of heat stress as an adult?
Dr. Jimena Laporta (28:44):
That's a good question. I don't think we have a lot of data to show that. I think, I, I think the first generation is preparing for the worst in a way. You know? 'cause Sensing the environment in utero is not good. So let's just methylate these genes here and there. Let's not grow, let's stop here. Let's save energy. So I think that the modifications that we see in that first generation are preparing them for a harsh environment. So we have looked at epigenetics in the mammary gland of those daughters in their first lactation. We see hundreds of genes that are differentially methylated, but a lot of those are involved in pathways that are, you know, very common for many tissues. You know, like secondary, secondary messengers cyclic a MP, so like very conserved pathways that are very important for any physiological function.
Dr. Jimena Laporta (29:48):
So the impact is, is very broad. We also look at the liver to kind of see like, are those differences that we see in the mam gland unique to the mam gland, or are they spanning across, you know, other tissues? And we saw 50 genes that were differentially methylated in the same genes pattern. And it's interesting, we're trying to dig farther into that and, and, and, and look more into, but I honestly don't think it's about one gene, two genes, three genes. It's really a holistic effect that heat stress is having. But I, I still look at
Dr. Brian Gerloff (30:29):
That, and this might be hard to discern experimentally, but would any kind of stress produce similar effects epigenetically cold stress societal stress Interaction or I, or would it produce some of the same and then others that are unique to the heat stress?
Dr. Jimena Laporta (30:58):
That's an excellent question. I think one thing we have to remember is that when I think about dry cows, the stressors are cumulative, right? So if you have overcrowded dry cow pen and their heat stress, that's not gonna go well. Right? so I think there, there, there might be, there are shared responses of most stressors. I think the uniqueness about heat stress is it's, it's, it's chronic at least in Florida, right? The, they can't skate, right? So if you overcrowd, there are some cows that are gonna do fine, some that are not. So the effect, it's sort of more diluted in the herd in a way, is we all know it's not good. But I think too, that those differences might be due to the intake, you know, some dominant cows are not gonna let other cows eat. So I'm, I don't think you're gonna see a consistent effect in your herd. You will see some cows doing better than others with that specific stressor. So I think heat stress is, is one that affects everything right. In the animal. Yeah.
Scott Sorrell (32:08):
Dr. LaPorte, you're, you're, you're painting a a dire story here, a dire picture, right?
Dr. Jimena Laporta (32:28):
Yeah, well, like because
Scott Sorrell (32:30):
because It'll take years to get out of it, right?
Dr. Jimena Laporta (32:32):
Right, right. And I think that you know, my, my, my take home message is that, hey, look, dry cow, heat stress, you, you can think of, all right, it impacts the cow that it's under heat stress. It's kind of intuitive, but the generational effects are not. So try to show that. It, it, it kind of brings some food for thought. It's like, okay, you know, it might, it, I'm not saying it's more or less important than, than lactating cows, absolutely not. But I think it brings the discussion of even, you know, in the Midwest, in Wisconsin, two months of heat stress, but we have a lot of cows, so you can impact a lot of generations even then. And our cooling systems are not that, you know, I'm not gonna say they're not great. I, I've been to farms that they do an excellent job, even with the dry cows. And it's, it's amazing to see. But it, it, it's not in every farm. And I, I forgot your question actually.
Clay Zimmerman (33:35):
Is there anything we can do?
Dr. Jimena Laporta (33:37):
Yes, yes, yes. There's many things we can do. Okay, good.
Clay Zimmerman (33:40):
Is there any good news?
Dr. Jimena Laporta (33:41):
Yeah, I'm a very positive person. I think so I like to think, well, what can we do to, to mitigate this? And obviously cooling is, is one of them, right? Just helping them thermoregulate, how they help their physiology to be back to speed. And, and when you think about dry cows that gestation allow that gestation to be under thermo neutral conditions nutritional like we talk about that briefly. Not only from the feed stuff you're feeding, I'm not a nutritionist just a disclosure here, but that, you know feed stuff that generates less heat or things like that. Supplementation of fat protein you know different supplements. There's a lot out there to tease out what's the best one. It's hard for, especially for producers when they have all these options. But, you know, east base nutrients, vitamins, minerals, trace minerals amino acids everything you, you, anything that can help that cow mitigate the negative effects of heat stress metabolically help them thermoregulate, help them overcome the, the protein deficiencies that they have through the reduction in feeding, intake, fat metabolism. So anything we can do to help them, I'm sure it will.
Clay Zimmerman (35:07):
But I think it's fair to say there's no magic bullet. You have to call these cows.
Dr. Jimena Laporta (35:13):
I don't think there's a magic bullet, unfortunately.
Scott Sorrell (36:24):
As in everything, right, there's a lot of research yet to be done on this. Yeah. Things that keep us be
Dr. Jimena Laporta (36:30):
Yeah. Keep you busy.
Scott Sorrell (36:31):
Can you talk about maybe just one or two of the key things that you're looking forward to studying in the future? Some things that are gonna have an impact on the industry?
Dr. Jimena Laporta (36:40):
Yes. we're, we're focusing a a lot more in the, what I call perinatal programming. So not just the, the, the in utero effects, but also one that once that calf is born in the prew phase, we're trying to develop cooling mechanisms for, for calfs. And we have done that in the last four or five years working now with the Dairy Land Initiative in Wisconsin. They with corny halfback and trying to think outside the box, you know I think with everything that's going on in our industry, well, our heifers are very viable
Dr. Jimena Laporta (37:48):
So trying to tease out what are the potential interactions with that, and trying to stimulate Maori growth by cooling them through nutrition. And one thing that I, I'm starting to talk more about is the early life mammary growth. That it's important, right? When we, when we think about the mammary gland, we typically think of, okay, let's influence, you know, components through feeding. When she's lactating already, I'm talking about early on the foundation of that tissue and how we can manipulate that in a way for, for the better, right? And through nutrition, through feeding them better, through cooling, through a lot of things. So that foundation will then lead to better cows.
Dr. Brian Gerloff (38:40):
Ha. Have you or anyone else looked at these same effects in beef cattle
Dr. Jimena Laporta (38:46):
Effects on the calf?
Dr. Brian Gerloff (38:47):
On the calf? Yeah.
Dr. Jimena Laporta (38:48):
There's, there's a lot of research in beef cows, mostly from the muscle perspective. Like, you know, the, the fibers and, and how that impacts the difference with, with beef cows is that the calf states with the cow for a longer period of time, and so the influence is more direct. So it's harder to tease that out. The fetal programming effects
Dr. Brian Gerloff (39:14):
Oh, versus the effect directly on the mammary
Dr. Jimena Laporta (39:16):
Gland. Yes. Yep. But yeah, there, there's, there's research. I mean we have done some work in, when, while I was in Florida with Dr. De Lorenzo in, in Mariana, where we offer shade to beef cows with or without their calf. We did a couple projects. And it's very interesting. You, you see impacts of simply shade,
Dr. Brian Gerloff (39:36):
Because I, I think of my clients over the years, and probably the beef cattle are at least as heat
Dr. Jimena Laporta (39:43):
Stressed. Oh yeah. Cattle. Yeah. And mostly like, a lot of those are exposed to solar radiation, which is another killer.
Clay Zimmerman (39:53):
Jimena. I'm curious, in Wisconsin, how do you impose heat stress there?
Dr. Jimena Laporta (39:58):
Well, we have a shorter season, right? But it's, it's fairly intense, I would say. So, according to, I, I was looking at some data a few years ago with threshold of a THI of 68 cows in Wisconsin would experience at least 13, 14 hours a day. What we have going on is that they have that nighttime to cool off slightly, so to release the heat accumulated through the day. So that's good for them. So that's the impacts are probably less severe because of that. So we either have to do it in July and August. We have used electric heat blankets as well to, to stimulate heat in, in those cows. And yeah, we finished a project last a couple years ago, and we did a transition cow study 60 cows with blankets.
Clay Zimmerman (40:53):
So you were talking earlier about doing some ca some heat stress work in calves. So is that, what does that shade or no shade
Dr. Jimena Laporta (41:02):
With calves, what were in, in Wisconsin, what we're doing you mostly see calf hutches there, which are designed for winter, not for summer. So there are some things that farmers do in the summer. They change the orientation, they raise the hutch, and there are things, easy things that we can do, implement to improve the ventilation inside the hud. It gets very hot in that. Hu if you haven't tried, I invite you to go in. I've done it. I have pictures. It gets very hot in that hutch. So what we're trying to do is provide fans active cooling to release that heat the, the, the accumulated heat inside the hutch. We have done that different prototypes to, to look at that using solar panels to power fans and redirect the air inside. And I guess the main effect that we see is an improvement in air quality.
Dr. Jimena Laporta (42:00):
We see a lot less bacteria build up in those hutches, which obviously it's gonna be beneficial. Less ammonia. So it's, it's in its infancy because, you know, at the farm level, those things are still hard to apply at a larger scale. In Georgia, we did a positive pressure tube for calves kind of, again, thinking outside the box, this is a drain tile with a fan, and then we put holes. And so each, each calf has had five holes and we put a mister inside that tube. Yeah. We get creative and Wow. And yeah, now in Wisconsin this summer, we're gonna do a project in a commercial farm. They install positive pressure tubes. So we're gonna test those. So, I mean, farmers are very looking forward to solutions. And this particular farm, they have a heel in right next to their barns or ventilation is really bad, and they notice that. And it's like, our calves in this barn do awful
Dr. Laura Niehus (43:12):
Hona, quick question for you. You said that you did 60 cal heat blanket? Yes.
Dr. Jimena Laporta (43:18):
How did I survive that?
Dr. Laura Niehus (43:19):
How?
Dr. Jimena Laporta (43:20):
Well, my student almost quit, but she's defending in a month, so she'd survive. So was
Dr. Laura Niehus (43:25):
That 30 blankets Yes. That you were using? Oh my gosh,
Dr. Jimena Laporta (43:28):
Yes. Yes. Wow. So we, we kind of adapted the model that Lance Baumgart lab used. We did some modifications to, to to make sure that the blankets were 'cause stay on for that long because it was 11 weeks. We did four weeks pre Calvin and four weeks, if I remember post Calvin. Wow. So yeah, it was, it was hell.
Dr. Laura Niehus (44:11):
Should be good data. I hope
Scott Sorrell (44:15):
Dr. Laporta, as we begin to wind down here, is there any key points that you're gonna talk about in your presentation that we need to explore just a bit here?
Dr. Jimena Laporta (44:23):
Yeah, I think I can sort of summarize what my take home message is.
Scott Sorrell (44:28):
Hold that thought. We'll do that at the end.
Dr. Jimena Laporta (44:30):
Okay. Well, so with this presentation today I'm gonna focus what we were talking earlier today that dry cow under heat stress, what happens to her in her neck, lactation from a mammary perspective a little bit. I'll show some photos to visually see what the tissue looks like. They have less alveoli, which is the milk secretory unit of the gland. So they are smaller, they are less so the way I like to think about it is like, you have a factory with less workers, so you're not gonna get to work done, right? And so that's from the cow's perspective, and obviously they produce less milk for entire lactation. And then from the daughter's perspective trying to recap what my slides are. Okay. From the, from the F1 perspective, I'm showing the impact on her mammary gland.
Dr. Jimena Laporta (45:26):
So they have smaller otters. So when we dissect the other, we open it up and we see what's inside. 'cause That's one of the things like in early life, you see no, not much change going on externally, right? Like they are just, you know, growing at the same rate of the body. But when you look at the tissues that are inside, that's a different story. And so those are growing very differently. The parenchyma that is going to become that future secretory tissue is growing exponentially, actually 25 fold increase. We have seen and so's a lot more that we can see to the naked eye, right? So trying to show some of that data. I don't go in depth here because of time but that, and then a little bit on the F two, like there's survival. It's also impacted productive life milk production.
Dr. Jimena Laporta (46:23):
And gonna take a peek on her mammary gland and, and seeing that proliferation is impacted. They also have less estrogen receptor in that gland. And we often not tend to think about estrogen at this early life stage. But it, it's important for that growth of the gland and a lot more research that, you know, van Amber even Capco acres labs have started a few years ago, is manipulating that early life maverick than through nutrition in their case, but manipulating that maverick then to make them more proficient at what they do later in life.
Scott Sorrell (47:08):
Interesting. That's gonna be a great presentation. What I'd like you guys to do right now is come up with a couple key takeaways that you'd like to share with the audience and kind of go around the table here and human I'll, I'll leave you till last, but and I'm gonna start off with Clay.
Balchem (47:25):
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Speaker 7 (47:52):
Easily lead off batter.
Clay Zimmerman (47:52):
Yeah, so a couple things actually, I wanna clarify. Yes. A statement you made much earlier in our discussion when you said it's doesn't really get that hot in Florida, I think. Yeah, I think you actually said that. I think
Clay Zimmerman (48:11):
I think what you met is it rarely gets over a hundred degrees in Florida, right? Yes, exactly. But it's in the nineties. Yes, yes. Persistently in the summer with really high humidity. Yeah. So it's very oppressive, but
Dr. Jimena Laporta (48:24):
The, the problem is the humidity, if you have like 85 in, in Wisconsin, it's not terrible, but in Florida it's hello, right?
Clay Zimmerman (48:33):
So key take, the key takeaways really are you need to cool your dry cows. I mean, these impacts
Dr. Jimena Laporta (48:40):
Simple. Yeah.
Clay Zimmerman (48:42):
I mean, you've, it goes out two generations now, right? You know, we know these effects are going out through the granddaughters. I'm very curious to see your F three data. Oh, I'm
Dr. Jimena Laporta (48:56):
Too when
Clay Zimmerman (48:56):
You have that. So so yeah, it's it's, it's pretty, pretty cut and dried as far as I'm concerned. Yeah.
Scott Sorrell (49:03):
Good. Thanks Clay. Dr. Gerloff, any thoughts, learnings, key ideas you'd like to share?
Dr. Brian Gerloff (49:09):
Well, I, I guess one thing that struck me, one is obviously cooling the dry cows is even more critical than historically we have viewed. And, and the other thing is it, so in probably the last 10 or 15 years, I've been amazed at how many studies are showing these epigenetic effects that what we do today has an impact so much farther into the future than we've even comprehended. It's sort of like in the Bible, it affects the children of the second and third generation and, and that it's both exciting and scary.
Scott Sorrell (49:57):
Yeah, yeah, exactly. Back.
Dr. Jimena Laporta (50:00):
That's a good way to put it.
Scott Sorrell (50:03):
Laura, what's your thoughts?
Dr. Laura Niehus (50:04):
Yeah, I think one really big takeaway that I've seen from this podcast, at least today, is that it's more far reaching than kind of maybe just affecting the Mamm Marie clan. You know, as you were talking about the adrenal gland and looking at the liver, and that there was really whole cow effects on these calves from heat stress dams, and that you really see it impacting the hormones and that sort of thing. And so I think that it's clear that we don't know the whole story yet. I mean, we see it in the reduction in milk yield, but now trying to figure out exactly where that's coming from is gonna be interesting to see. Yeah,
Scott Sorrell (50:44):
Good comments, Dr. Laporta final words.
Dr. Jimena Laporta (50:48):
Yeah, I think I, I enjoy the conversation. I always get new ideas and perspectives when I do this thing, so thank you. I guess from my point of view the take home or the, what I get from, from our conversation is that heat stress is more than just lactating cows. That's the first thing that come to mind, right? The, our lactating cows and 100% on spot, right? But it's about kind of expanding our, our, our thinking a little bit in those dry cows and the generational effects that they have in, in, in at least two generations and potentially three. That third generation is gonna be the unexposed one, because in utero you can have, you will have the, the germline that will give rise to the second generation. So they are technically indirectly exposed as well, but the third generation has not experienced any of that.
Dr. Jimena Laporta (51:49):
So it's very interesting to see that there's a lot of work in other species showing that even the F three can, can be impacted. I think the uniqueness of this work is that it's in cows, right? Obviously with its limitations, but I think it's, it's bringing in a whole different conversation about epigenetics and how is it possible that we see these things down 4, 5, 60 years down the road. And I think it's scary, but it's also exciting to understand what can we do about it? But in order to fix it, we need to understand it first. So I think that's sort of what I'm trying to, to preach about. And you know, the, from the cow dry cow perspective thinking about the dry period as more than justification, and there's, there's a reason why someone a hundred years ago said, let's try cows, right?
Dr. Jimena Laporta (52:45):
And they were right. And I, I'm, I'm an advocate for that and, and I think it's important to provide them with a better environment while they go through that transition. I think it, it's important to think about that. And I think the third sort of thing that I wanna bring up is the early life calf that transition from the intrauterine life to the outside life. I think that transition is, is, is important too. And we can, we can manipulate, and that word sounds a little scary, manipulate, but we can influence
Scott Sorrell (53:50):
Excellent. Jimena excellent conversation. Thank you. It's been very interesting. You're always a great guest,
Dr. Jimena Laporta (53:57):
Us. Yeah. And thank you for the coffee
Scott Sorrell (53:58):
You're very welcome. Clay. Laura, thank you for joining us, Dr. Ger off thank you for your insights, your expertise. Been a great guest today. Thanks for joining us here.
Dr. Brian Gerloff (54:08):
It was my great experience and I think I got more out of it than listening to a talk.
Dr. Jimena Laporta (54:14):
I hope you come to mind though. I'll
Scott Sorrell (54:17):
Absolutely. And to our loyal listeners out there, thank you for coming along with us on another episode. Hope you learned something, hope you had some fun, and I hope to see you next time here at Real Science Exchange, where it's always happy hour and you're always among friends. Hi, I am Scott sra. I'm here to invite you to a very special event at the upcoming ADSA conference in Louisville. It's gonna be a bourbon tasting. We're calling it bourbon and brainiacs. Now, why do you call it bourbon and brainiacs? Because we're gonna have all your favorite professors there doing a bourbon tasting. We're gonna have six to eight bourbons there. We're gonna be recording a podcast and doing the tasting. While we're there, we've even got a a bourbon, a barista, which I'm not sure exactly what that is, but we're gonna have one of them there. Now, listen, this is only for 120 of our favorite friends. That's all this place holds. We're gonna have it at the Fraser Museum. It's a bourbon museum there in Louisville, and so only 120 people can can fit in there. And so we want you to be one of them. And so to become one of the one 20, all you have to do is go to alchem.com/bourbon and register. Once those 120 slots are gone, they're gonna be gone. But I hope to see you there.
Balchem (55:36):
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