[music] Welcome to Scoop & Scale, where we dish up the science and weigh the facts about mostly equine nutrition. I'm Jill Jackson, lifelong equestrian, podcast producer, and pony owner. I'm a dressage rider and at-home horse keeper, living the challenge of managing easy keepers on multiple acres of pasture. And I'm equine nutrition consultant, Dr. Claire Tunis, of Clarity Equine Nutrition. I develop diet plans for horses ranging from metabolic seniors to Olympic athletes. I also consult for equine nutrition companies. I'm a scientist, dressage rider, and pony club mom. Claire and I have been horse friends for almost 20 years. And like all good horse friends, we're always talking horses. We talk about the challenges of managing our horses, our riding struggles, feeding horses, and what's going on in the wider equine community. This podcast is a place for us to have conversations mostly about equine nutrition. It's for anyone who wants to make better choices when it comes to feeding their horses. And before we get started, a quick disclaimer. The information in this podcast is general and not meant to replace the individualized advice of your own qualified equine nutritionist or veterinarian. And while I have a PhD in nutrition, I'm not a veterinarian, I can't give medical advice. With that, thank you for joining us and we hope you enjoy the following episode. Claire, you just got back from the Kentucky equine nutrition conference in O'Calif. Where you heard from a number of leading experts on lots of interest in equine nutrition-related topics. I did. It was a great couple of days and it was fun to hang out with a whole bunch of nutrition nerds, all my peers. And lots of people from the feeding industry and yeah, it was two days of great content. And a really interesting range of topics, very applied topics which I always really enjoy about this conference. It's very real world information that we can really kind of go home and use. Everything from Dr. Pagan presenting data on effective ways to cool horses. He's doing some really neat stuff with, you know how a lot of show horses now have to have microchips put in them for identification. Yes. You can also have similar, similar technology type microchips that actually read the temperature of the muscle that they're embedded in. Fun fact. You can. Yeah. My horse has that microchip. Yeah, well most of us do have the microchip. I think this is a different microchip, right? But it's the same, it's the same idea, right? And so the microchip. Wait, so is the temperature one? Your horse has, you have a temperature one. Your horse has the temperature one. Oh really? Yes. Yes, I'm not cool. I'm living in Iowa with my field vet with my fancy microchip. That's so funny. I did not really, I knew that whole conversation about Jill getting her horse microchip. We won't even share with everybody. But anyway, I did not realize you got a fancy one. I don't know that mine does temperature. I doubt it. It's been in there a long time. But anyway, yes. So there are microchips that consents temperature. And so he shared some really interesting data where they could, you know, work horses get them hot, see what the muscle temperature was and then use different cooling strategies to see which ones were the most effective at bringing temperature down versus say just doing a rectal temperature which doesn't really monitor what's going on in the horse's muscles. So that was fascinating. So everything from that to omega three supplementation in people. That was fascinating. And relating that to what we know about in horses and there is a very cool, like skin prect test that you can use for monitoring your own omega three status. And there's a ton of really good data about the importance of, you know, human omega three status and health consequences. So massive studies, tens, hundreds of thousands of people over many, many years where they've looked at, you know, influences omega three status on your heart, health, diabetes, stroke, risk, mental, acuity and all that kind of thing. And it's just fascinating. So there is now a blood spot test on the market for people that you can test your own blood omega three status. And then when you get the results back, you go online and punch your results in and they tell you how much you should be supplementing to get your omega three where it needs to be. So yeah, really, just really, really interesting stuff. Well, several of the talks were tied to the nutrition of broodmares and foals. And we do get quite a few questions about feeding this group of horses. And given that we're entering the sport horse breeding and fooling season in the Northern hemisphere, I thought maybe we could talk about this topic today and some of the things that you learned while you were at the conference. Yeah, those were fascinating talks. And I'd love to share some of those things that we learned. And I can hear all the gilding owners going, oh, this episode's not for me. But I promise, even if you're a gilding owner and don't have any interest in breeding, well, there are some really fun nutrition nerdy type tidbits that we learned. I just think of fascinating. So I hope our gilding owners will stick around and listen because I just think they're fascinating. You'll really be able to impress your barn friends next time you're hanging out and they're bemoaning about something with their horse. It may be linked to something that we cover here that I learned about at this conference. We're all going to have that friend. It's like, oh, I'm going to buy a baby horse and I'm going to raise it. It's going to be wonderful. You can be the smart friend that has the answers for that person. Yes, all the things that hopefully we don't scare away too many people that are thinking of breeding because basically what I came away, the long and short of it is, is we know a lot about feeding mayors and foals and there's an awful lot. We still have to learn. Well, when we breed a mare, I think it's safe to say that most of the attention is on the foal and what it will accomplish later in its life and the foal is the focus. As a result, a lot of people think about full nutrition starting when the foal is born or even later when it's weaned. Would you agree? Yeah, absolutely. I think that a lot of the time we focus, a lot of focus gets put on the stallion initially, because especially if you're a single mare owner, you kind of have the mare that you have. You have to choose a stallion for your mare and there's so many stallions out there that are vying for your attention. So you use a lot of focus put on the stallion and you want to make sure you make the right pick and it's going to complement your mare and you're going to end up with a foal at the end that's going to go on and do whatever it is you hopes and dreams are for that foal. So a lot of attention gets put on the stallion that makes sense. If you're actually a breeder, hopefully you've put together a well thought out group of brood mares that have specific traits and bloodlines and things over time. But again, each year you're having to make a stallion selection for each of those mares. So again, the stallion gets a lot of focus. And then of course, the focus is on the foal because at the end of the day, that's the whole reason we're breeding the mare in the first place is to get a foal. So then the foal gets lots of attention. So there's a lot of interest in feeding the foal correctly to avoid complications and to have the greatest chance of success. But to your point, I don't think as much consideration is given to the mare or even really thinking that foal nutrition begins at conception. And I would argue that maybe even it starts before conception and marine nutrition's vital to the health and longevity of the foal. And we heard a lot about that at the conference. So tell us more about that. Yeah, so when I started doing equine nutrition, we think about the mare nutrition as being important because the nutrients pass, obviously, while the foals are new to row, the nutrients have to pass from that mare across the placenta to the foal. And so we're feeding the mare well so that those nutrients are able to be available to the foal. And so we do think that's what kind of thinking about feeding the mare and feeding the foal through the mare that way. And if we take vitamin E, for example, it doesn't actually cross the placenta. It's passed the foal in the milk, right? So that's an example of it as it passed through. So you have to ensure that the mare is getting optimal vitamin E nutrition during pregnancy. So in that last trimester, her vitamin E is where it needs to be so that there's adequate vitamin E in the colostrum that then gets passed to that foal in the milk when it's first nursing and takes on the colostrum, it's going to get all this vitamin E at that point in time. So it is just this pass through. But we realize now it's so much more than just that. It's more than just feeding the nutrients to the mare so those nutrients can get to the foal. And the mare is essentially programming the foal through epigenetics. That sounds a bit space-aged. What is epigenetics? I know, it's appropriate, right? We've got people circulating around the moon. It sits this week. So it's a space-aged science. It's all a thing right now. But yeah, epigenetics refers to the way that your behavior and the environment can cause changes that affect how your genes work. So epigenetics turns genes off and on. It doesn't alter your DNA. Right? Your DNA is your DNA. But epigenetics is switching on and off of switches in your DNA. So what is that?
mean in context. So in this context of like the nutritional status of the mayor, her, for example, her metabolic status, whether she's suffering from systemic inflammation and you know, things like that, they're all going to regulate how the genes of the fall are expressed. Right? So they aren't changing the falls DNA, but they can impact, impact whether switches in that DNA are turned on or off. And I think a good example again is with vitamin E, right? There's a neurologic condition called NAD. And it's linked to the vitamin E status of the fall. So we don't know yet what the gene is for NAD, but our current understanding is that if you're a fall with a genetic predisposition for NAD, like your DNA sort of for one of the better expressions puts you at risk of getting NAD. And if at a specific moment in time that fall finds itself to be vitamin E deficient, then the gene for NAD gets switched on. Right? And this is irreversible, like it's switched on forever. And then that fall will develop NAD and display neurologic symptoms later in life. Right? So in this case, this is specifically what we call nutritional mix, right? The nutrition and gene nutrition, nutrition impacting genes. And nutritional mix is a form of epigenetics, right? Your environment influencing your genetic outcome and how your genes act, so to speak. So the environment created by the mayor while she's pregnant can impact the fall's long-term well-being and performance ability. Is that right? Yeah, exactly. So mayor nutrition and management during pregnancy and beyond is truly as vital. And yes, except before, it's like so overlooked, so commonly overlooked. And beyond early growth, milk production, which I think everyone thinks about when they think about marrying nutrition, it's about, is the mayor making enough milk for the fall? Is the mayor producing enough nutrition for the fall? But the mayor is also impacting what are referred to as developmental origins of health and disease, right? And so these developmental origins of health and disease are the conditions around the time of conception and gestation and then early postnatal life when that fall is really young, after it's born, that influence long-term health. So it's more than just the nutrition. It truly is the entire environment that that mayor is creating for the fall. That's all I have to think about. Right. Did I say that we have a lot still left to learn? Right? And there's, it's kind of mind-blowing and it's sort of, yeah, we just, we don't know yet exactly how this works. And it's funny too, when we talk about that the mayor's, everybody talks about the fall, and they never talk about the mayor's, it's always like, right at the last 30 days when the fall is about to be born, the people are like, "Oh, what should I be feeding my brood bear?" It's like, wait a second, how long has it been pregnant for? Months. No, it's true and it's so true and so much development goes, the thing is, the problem is, right, is that in the first trimester, you can't see what's going on. Like the mayor doesn't change shape, just anybody changed that much shape in the second trimester either. So she doesn't even look pregnant. Like when you look at her, you don't even really think she's pregnant. It's not until the third trimester where you're getting a lot of like skeletal development in that fall and really a lot of like, you know, the fall is really developing a lot of the mass in that third trimester that you start to see. I hope you're seeing a change in the size of the mayor because the fall is, you know, going from being tiny to potentially say like, 80, 100 pounds or whatever. So that mayor physically gets bigger. That's when we go, "Oh wow, yeah, the mayor's pregnant. I should feed her something," right? But that first trimester, I mean what's happening is, you know, you're getting a lot of cell division, right? It's like, it's cellular level stuff, but from a genetics standpoint, it's vital, right? It's all the genes being turned off, switches being turned off, cells dividing. Then you have percentile development because you have to develop a really good percentile that's going to be able to shuttle the nutrients to the fall and take waste products away from the fall. So you have, you know, that has to develop and you have to have a good strong placenta to be able to then get all the nutrition to the fall. So it can grow in the third trimester, but you don't see any of that going on outside them there, right? So I think it's, yeah, it's easy to not really think about it until, "Oh, I see the other thing. I see, you know, somebody who's, you know, got a mayor and they've decided they're going to breathe. They're going to breathe that one horse. They're going to breathe. It's going to be there. They're going to breathe their heart horse from their mayor." And it's the opposite, like from day one of conception, they're wanting to like almost like overfeed her, right? Like, it's just like, "She's pregnant, so I must have to do something dramatically different." And the reality is probably no, not really, but it's just important to understand that those, at the end of the day, you just need to feed a correctly balanced diet, you know, the correct number of calories, maintain your mayor in good weight, but you know, she's not a machine, right? I mean, I think we send a sign of sound. I feel like having a feminist moment, right? But I just feel sometimes like these mayors get treated like incubators and they just, just kind of, you know, get bred back to back and they're not really seen as that important to the overall mission of producing a fall. And the opposite is true. In fact, they are the very foundation of your breeding program. You are nothing without your breed mayors. Okay, so we certainly have a lot to learn. That's it, the episode's over. Just so pumped. We said everything. I know. So, you know, there was some other interesting terms, a term that I had not heard before that I learned was predictive adaptive response. Well, I bet you I could figure that out if I thought about it, but why don't you just go ahead and tell us what that's all about. Right, so when the fall is in the uterus, right, it's adapting to its environment to maximize its chance of survival. So how it adapts in that environment can influence then how it responds through its entire life to various situations. So, for example, if a nutrient's deficient while the falls in utero is going to adapt as best it can to maximize its ability to use that nutrient efficiently, right, it's going to try and figure out how to get by with less. And it'll use that those, you know, maternal cues to predict what its postnatal environment will be like, right, because it doesn't know any different. It thinks that the environment is in while it's in utero, it's going to be similar after and say one, right. So it's setting itself up for life, right. So this is a great survival tactic, right. I mean, if you're if the mayor is in not great shape and nutrition is lacking, then all the signals going to that fall, you better be good at surviving in an environment that doesn't provide you what you need, right. And then if you're born into an environment that doesn't provide you what you need, you're more likely to survive, right. But you, so you may be metabolically more efficient, right, and able to get by on less great survival strategy. Except it's not so helpful potentially if the environment that you then end up being born into turns out to be super abundant, right. And has lots of nutrition because you've been wired to survive in an environment that doesn't provide you a lot. And then you find yourself an environment that's like plentiful, right. So yes, but there's a potential there then for that horse to be at greater risk, for example, say of like obesity or metabolic disorders, for example, because of how it was programmed, how it adapted in utero. So if I'm understanding this correctly, what you're saying is that genes set your potential and then the environment impacts how these genes are expressed. And some of these effects can last for a lifetime. Yeah, absolutely. I mean, we really are setting up false for life through, you know, through through the entire pregnancy, right. So my point of fall nutrition starts at conception, although maybe even before, I've said that for a long time, and I feel very vindicated now, right. That I've heard this this research. So, malnutrition during pregnancy has the potential to impact the false metabolism, the growth patterns, potentially long-term health and performance. You really are building an athlete from day one. Yeah. So was there any information shared specifically about malnutrition and its impact on the fools? Yeah, I mean, all the information that we've discussed so far was presented at, you know, at this conference by Dr. Pascal Shavett Palma, and she's a researcher from France and since 2006, she's led the placenta environment and programming of phenotypes research team at one of their research institutes. And, you know, she also shared that even, you know, she said so many interesting things. I mean, for example, like even a modern
reduction of energy intake of say 80% of what the mayor's actual requirement is can result in adaptations in the placenta. So she's really doing research like looking at the placenta, looking at embryos trying to figure out, you know, what effects different diets and conditions are having at that level. And so what they found is that when you restrict energy intake by 80% of requirement, you'll see things like increased fast-calization in the placenta and increased nutrient transport, which again, so speaks to my, you know, what I shared earlier that she shared with us, which is that, you know, falder in that sort of environment in utero are, you know, the environment is trying to do its best to set that fall up for success as much as possible. So in turn, while the falls that have fallen to these mayors didn't demonstrate, they didn't show any difference in birth weight when they were born because of that increased fast-calization. So even though the mayors didn't get fed enough calories because the placenta adapted and sent more blood flow and more nutrients to that fall, there was no different in birth weights. But what they did see were were impacts in long-term outcomes. So the falls born to those mayors showed things like delayed testicular maturation. They had reduced insulin sensitivity at adolescence and they also had reduced cannon bone width, right? So these are things that you won't see potentially for money months if not years down the road. So changes were happening in the programming of these falls in utero. They look completely normal when they were born compared to falls that, you know, didn't have that new energy deficit. But there were consequences down the road. What about a mirror that's being overfed? Do we know what that may do to the fall? Yeah, she shared some interesting information about that too, especially in first-time mayors. So you know, when they're getting overfed during pregnancy, you know, it can impact the fall. Specifically mayors that are obese in pregnancy may have offspring that are insulin resistant, right? They may have low grade information and they also have an increased risk of osteocondrosis, right? Which is joint disorders when those falls are about a year old. So yeah, being overweight is also not good. So what's interesting is that the falls didn't show any difference in size again. So it wasn't a birth weight-related issue. It wasn't that, you know, because the falls were heavier at birth or what have you that that wasn't the issue. It was at the metabolic programming that was taking place while that fall was in utero was having an impact then on there, you know, down the road. So I think one thing that's important to say, you know, in regards, here is also the potential risk of breeding mayors that are already insulin dysregulated. And I do work with some of those mayors sometimes and you know, not from the fetal programming, you'd run environment standpoint, but I think that it's important to understand that pregnancy tends to make mayors a little more insulin dysregulated than what otherwise be, same as in people, right? So nature has created this situation that when you're pregnant, the goal is, I mean, you're sort of sacrificing yourself for the good of the unborn creature, right? Well, that's a human dog cat horse, right? Because at the end of the day, you want your genetics to continue and go on. It's about creating another generation, right? So on some level, you're sacrificing yourself for the good of the unborn unborn fall or whatever. And so you want to optimize growth of that fetus while it's in utero at the expense of the mother, right? And so the body naturally sets out the situation where it makes the mother a little insulin resistant in order to make more glucose available to the fetus, right? So it doesn't go to the mother because the mother becomes insulin resistant. So then there's more circulating glucose in the bloodstream that can go to the fetus for the fetus's growth. And that happens naturally. Like that's a natural thing. It's good. It's no problem. The problem is, is if you're already insulin resistant or insulin dysregulated before you get there, and then you add on this naturally occurring insulin dysregulation on top of that, in the case of some of these metabolic mayors, you could potentially push that mayor into a situation where she's at risk of laminitis. And we do see that. We do see mayors in the last trimester suffering with laminitis and that it's, I mean, crippling, right? It's really, that's extreme. It's heartbreaking to see. It's heartbreaking. It's a big welfare issue, right? And I can't even imagine being the owner of a mayor and being in the third trimester so close to falling and dealing with a mayor that's laminitic and potentially looking at the reality that you may have to euthanize your mayor because it's the right welfare decision for her. I mean, that would just be devastating. So I think you really have to think carefully about the realities of breeding a mayor if she has a history of being insulin dysregulated or has any history of laminitis. Because it's a bit of a, it's a real wild card. You don't know how she's going to react to, you know, that added insulin dysregulation that happens with pregnancy. And obviously because she's pregnant, there are going to be some medications that she might otherwise be given if she will laminitic that she won't be able to have because she's pregnant. And, you know, for those that are familiar with her pregnancy and people, it's the same reason why, you know, as people we go and we get tested for gestational diabetes, right? It's the same, it's the same concern in people we're doing it because there's concerns about, you know, overly large babies and then having dystosia issues and, um, obviously we're not worried about laminitis and human babies, but it is the same sort of mechanistic situation from a metabolic standpoint. So are there any tricks to getting mayor nutrition right? Yeah, I mean, we want to make sure that we're feeding a diet that supports conception, right, from the very beginning, um, and then supports the growing fall while it's in utero, as well as that ensuring that that mayor has enough condition on her when she falls that she can support a good lactation and create enough milk to support that fall. So we want her in good enough condition at falling that she isn't needing to draw too significantly on her own body reserves. And this is especially true if you want to rebreed her. So I aim for a body condition score of five or six at breeding time because mayor is that are either too fat or too thin are going to have a harder time conceiving. And then nothing much is going to change in that mayor's body condition during the first trimester or even the second trimester, like we talked about before, but in the third trimester, like I think I said earlier, you absolutely should be able to see that mayor getting larger because that fall is now growing quite significantly. And if that mayor does not appear to be getting larger, it means that that fall is getting bigger at the expense of the mayor because like I said, like nature is set up to favor the well-being of that unborn fall at the expense of the mayor if necessary. So if your mayor is not visibly getting bigger in the third trimester, that fall is going to be growing and it's just taking nutrition away from that mayor and condition off that mayor. And then when that mayor falls out, you're going to be in for a nasty surprise when you realize that she doesn't have as much condition on her as you thought she did. And now she's in a position where it's going to be hard for her to support that fall during lactation. So because, as I mentioned, the placenta development that occurs at the start of the second trimester, there is some increase in nutrient requirements starting at that time, but it's not much. And in fact, the difference in energy requirement between a mayor at conception versus at the end of pregnancy is about the difference between as if she like wasn't pregnant and was not working so it maintenance and her being in light work. And I think when people think about their horse being not working at all and just being in light work, maybe written three days a week for an hour, it's not much work. There's not a huge nutritional shift between those two. Now that's the nutritional shift of a mayor not being pregnant and being 11 months pregnant and ready to fall. So it's not a massive difference when it comes to calories, but what is super important are all the micronutrients that are being provided. It's really important that you're getting enough calcium and phosphorus and stuff. And so for mayors and good condition and for easy keeper mayors, you know, they often during pregnancy get by just being fed a really good quality forage and as you can probably guess what I'm going to say, a ration balancer. Always the answer. Just start with the ration balancer. What in doubt, right? Yeah, so the mayor, at least those who. First to try masters because there's really little increase in caloric need. As long as you're feeding really good quality forage, you need the quality protein. There's an arachnobalancer and then obviously it's vital that the calcium phosphorus needs are met. And the calcium phosphorus needs also need to be properly balanced for bone development in that fall. Additionally, you need adequate copper. That must be provided as well. This is really important. Copper is required for collagen formation and collagen is a foundation of all your bone, tendons and ligaments. So, if that mare is deficient in copper, that fall is going to be in a situation where it may not be able to develop good skeletal structure. And in fact, those data showing that falls whose mothers were copper deficient during pregnancy are at greater risk of developing OCD and joint disorders. And feeding the fall more copper after it's born doesn't reverse that risk. So the micronutrient status of that mare, while she's pregnant, is really important to the long-term soundness of that fall. As I mentioned earlier, vitamin E, right, that's important as it needs to be present in colostrum. So it's really important that the mare is getting adequate vitamin E in that third trimester. So I recommend that mayors have their vitamin E levels tested at the start of the third trimester. If they are deficient, you have time to get them back to where they need to be before they have to make colostrum right before falling. And then, you know, for those harder keeping mayors for the ones that can't just maintain themselves on origin of ash and balancer, or for mayors that are still lactating because they had it fall the year before, maybe they're still lactating and you've bred them. Those mayors obviously may need a more calorically dense feed to be added to their diet, but I try to stay away from feeding too much cereal grain to pregnant mayors because there is some research suggesting that these can lead to metabolic shifts in the mare that can have a negative consequence on the fall, such as negatively impacting cartilage and bone development. So I try to pick those, what feeds I do feed kind of carefully. And I also try to avoid making nutrition changes right around birth. I figure that it's stressful enough at birth on that mare. Like, first of all, if he's a maiden mare and suddenly she's like, what the heck is that practically? She's got a fall all of a sudden with no experience on what she's doing. Her hormones are all over the place, right? There's a lot of big changes going on. I don't want to throw a diet change on top of that. However, you know, a lot of mayors are going to need some amount of a more calorically dense feed during lactation, even if during pregnancy they were fine on just hay and a ration balance that they may need some more calories on the back end. So I do like to introduce a small amount of whatever that higher caloric density feed, whether that's a normal, it's a growth feed, right? I like to introduce a small amount of that in the last month before falling so that that isn't a new addition. Maybe that mare falls out, she holds her weight beautifully just on hay and the ration balance and I don't need that growth feed and then I can just remove it. But if it's already in there at like a couple of pounds a day, if we get to, you know, a couple of weeks after falling and we realize all this mare needs some extra support, it's already there. I can gradually start to increase it. I'm not adding something new to her and potentially kind of creating another change that she has to handle. I just thought of something. We're talking about the effect, I know. When we're talking about the effect of the maternal environment on the full well in utero, what about if the mare isn't actually the genetic mother of the full? Like embryo transfers become pretty common in performance horses because it allows the mare to keep competing well and other mare carries the full. What happens in this situation? That's a great question. I can see you've been, well, I was rattling on about feeding brood mare. So you've been sitting there thinking about uterine programming. We know that the size, the metabolic health and the nutrition of the recipient mare does effect fetal growth. We know that the size, metabolic health and nutrition of the recipient mare effect fetal growth. Yes, selecting a recipient mare carefully that's as similar size as the actual mother is very important, which I don't know that people think about that much when they're selecting resets, but that is something you should consider. And there are differences between breeds and the data presented at the conference recommended that recent mare is be the same breed as the false actual mother. And they look to how embryos that are raised in a recent mare behave on the outcome is a great way. It's actually using recent mare as a great way to separate out. What is DNA and genetic coming from the fall, so to speak, and what is actually the result of the uterine environment that the fall develops in. So it's actually a great way to do research. And the research that was shared at the conference showed that when you put pony embryos into draft mares, fetal growth actually increased by as much as 57% in some instances as huge. Wow. Yeah. It was funny. She said that she did not feel confident going the other way and putting draft falls into ponies because she just, but it's a bit of an unknown, right? It's unnatural. You wouldn't do that. I mean, obviously there's that scientific curiosity of what happens when you put a draft fall in a pony uterus, but what happens if something, you know, it wasn't good, right? So they haven't done that. But growth in these horses, when they put the pony mares in the drafts, the growth looked great up until about 18 months. However, it did affect metabolism, including insulin resistance at weaning. You know, these were noted in early life, similar work where pony embryos were put into thoroughbred mares showed, interestingly showed alterations in blood pressure shortly after birth. So there are some things happening when you, you know, when you put, you know, falls of one breed into mares of other breeds, especially different sizes. So they did put a large breed embryo into a pony size, Mayor? Yeah, it's not a draft. I mean, I said that she did say she didn't, they didn't feel confident putting a draft into a pony, but I think they did put some saddle bread, falls into pony recipients. And it was found to restrict fetal growth. And the falls were smaller at birth. They grew more slowly after weaning in another case. They have done that. And again, so doing this kind of research really shows the impact of the uterine environment of the host mayor having an effect on the fetus beyond genetics. Does the age of the mayor or how many falls she's had have any effect on the new fall or on the fall being borne out? That's a good question. There was actually another talk by Dr. Pagan. He has some phenomenal data looking at growth rates and falls. They've been collecting for many years in thoroughbreds around the world and they've put thousands of thoroughbreds. And so they've looked at that like they've looked at, you know, whether it was the first time mayor, but she'd had multiple falls and the effects that it's had. And again, Dr. Shavant Palmer also discussed it and falls born to first time brood mayors or what we call premier Paris mayors tend to be smaller. In racehorses by the time they were yearlings, Dr. Pagan showed that they've caught up with falls or born to mayors that have had multiple falls. So by the time they get to a year old, that difference has disappeared. And interestingly, we kind of know this to be true from other breeds. Like we know in cattle, right? Like anger, you know, sort of angus cows. We often like farm and beef producers will often use an angus bowl on their heifers when they have their first calf because obviously angus calves have smaller heads and they're small, a little bit smaller. And so they get less dystocia issues. Then and then the next time that cow gets bred, they'll put a different, you know, maybe the cows own breed fall, unbreed fall, unbreed ball. So yeah, we kind of know this in other species too. But embryo is from older mayors, show old to gene expression. So I think that's really interesting because it's not uncommon that people will decide to breed their older mayor, right? Especially if she has an injury or something or they just suddenly for emotional reasons decide, you know, 18, they want to breed their mayor and she's never been bred before. But they do see older gene expression that suggests that they may be developmentally delayed. And it's thought that that might be part of the reason why it's harder to breed some of these older mayors successfully because they're, you know, they're just not, you know, they're delays in the embryos and they don't function the same. And so I think that's also thought that there are shifts in the pathways responsible for inflammation, right? So they might see more inflammation in those older mayors that has an effect on the embryos. And so one thing I thought was really interesting is that regardless of the age of the mayor, if she's lactating while she's also pregnant, she's not pregnant.
Her pregnancy tends to be shorter and her subsequent milk production tends to be reduced, which can then impact the growth rate of that fall when it's born. And we see this a lot, right, in brood mares, because a lot of breeders breed back to back. So it's not uncommon that your, your mayor has a fall. You then take that mayor back to their breeding shed, you know, either on her fall heat or the next heat, and you're rebreeding her, you know, a couple of months after she's had her fall. And she gets pregnant, so she's got a fall at foot that's lactating while she's pregnant with her next fall. You know, that scenario can, can have an impact on the next fall when it's bred, like it's growth rate. So these falls may need more nutritional support, especially around month four of lactation when milk production levels tend to drop anyway, because she's already producing less milk because, you know, she was lactating another fall when she had a fall on her. This ties back to what you were saying earlier, because if the mayor is not in good condition when she falls, she'll have less body reserves to draw from to support lactation and produce milk. Yeah, exactly. I mean, it's, it's interesting. It's one of those things that when you think about it, this research, it's sort of not really surprising because, you know, to what you're saying, like if I have a mayor, she has a fall, I don't really feed her adequately during lactation. So she then uses a lot of her body condition to create the milk she needs for that fall. Meanwhile, I've rebred her. By the time that second fall hits the ground, I now have a mayor who's not in such condition, such good condition. She doesn't have the body fat reserves to generate milk supply. And so on some level, of course, a milk production is going to be lower for that second fall, right? Absolutely. Like keeping those mayors on, you know, good plane of nutrition and in good body condition is really important. And I'm surprised by, I mean, I've met more than, you know, one breeder over my career who, you know, it's just sort of accepted that periodically mayors don't take. They don't have a fall or that just happens, you know, every three or four years. We just don't get a bread and what have you. And I'm looking at this mayor who's so kind of spent physically, right? She's just, there is, she doesn't have enough condition on her. I just can't help but thinking that if you, if you could do a better job of maintaining condition on that mayor while she's lactating, she'd be more likely to get pregnant and is successful. And obviously, if you're a commercial breeder, skipping a fall in a year is, that's, that's real money that you're missing out on potentially, especially when some of these sports falls are selling for $10,000, $15,000, $20,000 as windlings. That's a lot of money to leave on the table. Who's buying a horse for that amount of money? Have you? I don't know. I don't think the horse market, you're not buying a horse for that price. I don't care that it's a full. You're not feeling it in utero. Faults in utero, $20,000 for wool blood fall in utero, maybe right away off, but I don't, you know, anyway, I think you're too low. Anyway, we're not going to talk about selling. What I mean, but still, I, that makes it even worse if I'm drawing in your right, right? There's even more money that's being left on the table if that mayor doesn't get bread. But I think the other thing to say or two is like when we talk about, you know, the condition and yeah, they don't get bread, but like, I've seen lots of reset mayors and they never look great and people just like, oh, well, it's just a reset mayor. She was just lame. So we bread her or, you know, I just have her for the breeding season and you can see their spine and their hip bones and they just, you know, they don't look thrifty. They don't look, what's that pregnancy glow? Oh, I don't have blood sugar. I can feel my blood for it. I'm getting back on my soapbox here. But I think that that's really right. But it's true. Yeah. It's really, it's sort of sad, you know, that people, you know, they don't, I don't want to say they don't care. It's not that they don't care. It's just that they have this in their head that like, oh, it's just a reset mayor. But, you know, she has a big responsibility. And like you said, like she's producing whatever full, you know, you've got going on in there. And so to not take care of those reset mares and treat them. Especially, especially now we understand all the fetal programming that's going on based on you to an environment and stuff, right? Right. It's not, it seems to we, I mean, it seems that we have a pretty good grasp on how to feed the group, mares for success, but there's still a lot we have to learn about the subtleties and the things that have the long-term effect on pools. Yeah, absolutely. Right. And it takes some really long research trials right off. And like some of the things that I've shared that we're seeing are affected by this are not obvious at birth, right? They may not be obvious for 12 or 18 months or maybe even longer, which makes it challenging to study, right? It's hard to do that kind of research, but yeah, but the, you know, Dr. Chavette Palmer and others are working to try and identify these epigenetic markers in embryos and placenters in the hopes of being able to develop tools for breeders and veterinarians so that we can better manage brood mares for optimal outcomes, you know, and hopefully improve the long-term health of our horse population because the reality is is that we really are setting up these horses for life by how they are fed, how the mares are fed, while they're pregnant, how the falls are fed when they're in utero and shortly thereafter truly does set that horse up for life. For our listeners, if you'd like to be a part of our conversation, please send your suggestions for future topics and equine nutrition questions to
[email protected] and is spelled out. You can also find clear at clarityequine.com. You know that if you're like us, you're probably listening to this while driving or doing barn chores, but when your hands are free, if you'd share it with your friends on social media and be sure to subscribe on your favorite podcast platform, it helps other horse lovers like you to find us. For the scoopinscale podcast, I'm Jill Jackson and I'm Dr. Claire Tunis. Thanks for writing along with us.
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