Ep. 091: How Many Times a Day Should You Feed Your Horse? Here’s What the Research Says

Episode Notes

Many horse owners focus on choosing the best hay, grain, or supplements, but research shows that when you feed can also impact how well your horse utilizes protein and amino acids.

On this episode, co-hosts Dr. Tania Cubitt and Katy Starr and guest Dr. Sara Mastellar, equine nutrition researcher and professor at Ohio State ATI, break down her research on meal frequency and protein metabolism in horses, including:

• The difference between “just feeding protein” vs. ensuring your horse gets the right amino acids
• Why feeding multiple meals a day can improve your horse’s nutrient absorption
• Simple, practical ways to adjust your horse’s feeding routine for better health

As Dr. Mastellar mentions, “Observation is central to good horsemanship.” If you’ve ever wondered whether your feeding schedule is truly working for your horse, this is an episode you don’t want to miss!

🎧 Listen now on Beyond the Barn!

Have a topic idea or feedback to share? We want to connect with you! Email podcast@standlee.com

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Connect with Dr. Sarah Mastellar on:

• University profile page with email address
• Ohio State – College of Food, Agricultural, and Environmental Sciences on facebook
• Ohio State ATI Equine Center on facebook

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Scientific references – 

Full list of amino acids - https://thehorse.com/113117/amino-acids-101/

• Mastellar, S. L., E. R. Share, J. K. Suagee-Bedore, K. Bennett-Wimbush, N. R. Liburt, A. Krotky, B. Cassill, K. L. Urschel, and P. A. Harris. 2023. 74 Effects of meal frequency on plasma amino acid concentrations in horses of various body condition scores. Journal of Equine Veterinary Science 124:104376. doi: https://doi.org/10.1016/j.jevs.2023.104376
• Share, E. R., S. L. Mastellar, J. N. Rumble, and M. L. Eastridge. 2025. Feeding and housing management practices of the Ohio horse industry: A survey. Journal of Equine Veterinary Science. Accepted.
• Brown, A. V., E. R. Share, N. Liburt, J. K. Bedore, P. Harris, and S. L. Mastellar. 2024. Effects of Meal Frequency on Heart Rate in Horses American Society of Animal Science Midwest No. PSIV-A-8, Madison, WI.
• Link to “Evaluating Body Composition of Horses” factsheet: https://ohioline.osu.edu/factsheet/as-1024

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*Views and opinions expressed by guests are their own and do not necessarily reflect the view of Standlee Premium Products, LLC.*

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Read full episode transcript

Katy Starr (00:01):

Hi, I'm Katy.

 

Dr. Cubitt (00:02):

And I'm Dr. Cubitt. We're going Beyond the Barn. Come join us on this journey as we bust equine and livestock nutrition myths, and interview some of the most intriguing experts in the country.

 

Katy Starr (00:15):

We'll go behind the scenes of how premium Western quality forage is grown and brought to your favorite farm and ranch retail store. We're so glad you're here.

 

Katy Starr (00:27):

Welcome back to another episode of Beyond the Barn, Dr. Cubitt, it's great to have you here with me today and to talk with a new guest.

 

Dr. Cubitt (00:37):

I am excited to be back, and I'm really excited for our guest today.

 

Katy Starr (00:41):

So, our next guest is an equine nutrition researcher and professor at Ohio State, ATI. Growing up on her family's dairy farm in New York, she developed a deep passion for horses through pony club, 4-H, and collegiate dressage. She earned her PhD in Equine Nutrition at the University of Kentucky and now teaches courses on equine nutrition, facility management and horse judging, while also mentoring students in research. Today she's here to share some insights from her research on the fact that how we feed horses can be just as important as what we feed. We'd like to welcome Dr. Sarah Mastellar to the Beyond the Barn podcast. So, thanks so much for joining us today.

 

Dr. Sara Mastellar (01:25):

It's great to be here. Yes, I teach courses about horses here at Ohio State ATI in Wooster, Ohio.

 

Katy Starr (01:32):

Excellent. And so, just before we get started, we like to make sure our listeners know that any of the topics that we cover on the Beyond the Barn podcast are more generalized and not specific to any individual horse or any specific situation. So, be sure to always work with your veterinarian and nutritionist before making any drastic changes to your horse's feed program. You can also reach out and talk directly with Dr. Cubitt or Dr. Duren on any specifics that you would like to know or if you wanted to get some more insight from Dr. Mastellar as well. So, why don't you just get us started by telling us a little bit about your background with horses and where you grew up.

 

Dr. Sara Mastellar (02:11):

Yeah, so I grew up on my parents' dairy farm. My mom always wanted a pony when she was growing up, so she got me a pony when I was growing up. Quirky O'Brien. And then I did pony club and 4-H, some low-level eventing and I thought I wanted to be a horse trainer. So, I went to schoolCazenovia College in equine business management or business management specializing in equine business management. And while I was there, I had some opportunities to be a teacher's assistant and a peer tutor and then decided, well, maybe I could impact the lives of more horses if I could become a people trainer rather than a horse trainer . So, that led me to look into grad school and the University of Kentucky, Lexington Horse Capital of the world, sorry, Ocala . So, I had the opportunity to go to grad school down there and got my PhD. I don't have a master's, under Dr. Kristine Urschel, focusing on protein metabolism in growing horses. While there, I helped teach as a TA and also as an adjunct at Midway University, got recruited to South Dakota State and was an instructor there for three years before moving to Ohio and taking this position in in 2017.

 

Katy Starr (03:30):

Excellent. And you've been there ever since, that's awesome. So, today's conversation, I think this is going to be really helpful for horse owners to give them a little bit more insight into kind of like their feed management and what could be kind of helpful for them. So, we're going to be discussing some of your research that you've worked on, the effects of meal frequency on plasma amino acid concentrations in horses of various body conditions scores. So, tell us what inspired this study.

 

Dr. Sara Mastellar (03:58):

Yeah, so I originally became interested in meal frequency after coming across some different situations where people were feeding regimens that were not twice a day. So, as I grew up in the northeast, everybody always fed their horses twice a day. Maybe some of the higher end barns fed lunch hay or something like that, but as I became more aware about how other people were feeding their horses, some of them only once a day, some of them more frequently, I wanted to know a little bit about how the tradeoff for time commitment, right? Because there's a labor aspect to feeding your horse more times a day how that impacts metabolism, physiology, welfare, how that impacts the horse, right? Because that's, that's what we're here about is the horse. So, changing meal frequency is something anybody can do. You don't have to have a special feed or buy a certain product. So, I thought it had some broad implications to know more about meal feeding frequency.

 

Katy Starr (04:53):

Excellent. So, talk to us a little bit more about the study itself. How did you guys set it up? What was the study duration, the horses that you had involved and how you chose them and everything?

 

Dr. Sara Mastellar (05:05):

Yeah, so we used our school horses here at Ohio State ATI and we did some screening to test and see their metabolism before getting put on the study. So, we did an oral sugar test, and we were looking for evidence of insulin dysregulation, any irregularities there. And that eliminated a few of our horses. So, from that pool we selected 12 and we tried to get a variety of body condition scores, but by the time we eliminated the ones that had some different results with the oral sugar test that kind of narrowed our, our range of body condition scores. The horses had a two two-week adaptation to the diet, and we aimed for sort of like a typical American feeding diet that people would feed their horses here in the U.S. and then the horses were divided into two sets of six and we tried to have a little bit of a range of body condition score within those two sets. We group housed them and then we brought them inside to do some behavior recording as well as catheters and taking blood samples so that we could measure plasma amino acids in their blood. They were on each treatment, so each feeding frequency, either once, twice, or three times a day for one week each. So, all horses received all of the treatments.

 

Katy Starr (06:29):

And so, in some of the stuff that I was looking at, you said that you use kind of like a random number generator. Did you keep the horses at certain time of feeding for like the same duration and then like the next wave you changed it from once a day to twice a day? Or how did you manage that process?

 

Dr. Sara Mastellar (06:47):

Yeah, so the random number generator was mostly to determine the order of the treatments and each of the horses within the set all had the same feeding frequency so that they didn't see the other horses get fed when it wasn't their turn to get fed . So, we wanted to make sure that like that behavior component was controlled for.

 

Katy Starr (07:07):

And what were your main objectives of this study through all this? Like what were you hoping to get answered in this process?

 

Dr. Sara Mastellar (07:15):

Yeah, so this study is part of a, a larger project evaluating the impact of meal feeding, frequency on metabolism and behavior. So, I think both of those components are of interest to horse owners and managers and and helping us make good science-based decisions.

 

Katy Starr (07:30):

So, talk to us a little bit about, because within the amino acids you kind of had those broken down into indispensable, conditionally indispensable, and dispensable. There are, and this is me included where this is, is getting a little bit more in depth, but talk to us about the differences between these amino acids and what you were kind of looking at when you were taking the measurements and everything.

 

Dr. Sara Mastellar (07:57):

Yeah, so those three terms are I guess classifications of amino acids and that allowed us to group the amino acids in a, in a way that helps us to tell the metabolic story. So, indispensable amino acids, those are the essential ones. They must be acquired in the diet by the horse for healthy functioning. The conditionally indispensable amino acids can be synthesized by the horse, but not in large enough quantities under some conditions. So, a growing horse, for example, might not be able to synthesize enough to maximally support growth of some of those. And then the dispensable amino acids, these are the non-essential ones. They can be synthesized by the horse as long as the horse has the ingredients to do so. They can be involved in moving nitrogen around the body and some other metabolism as well. But we're not as worried about getting those specifically in the diet. The indispensable ones are the, or essential amino acids are the ones we worry about most when constructing diets for horses.

 

Dr. Cubitt (08:59):

And just for our listeners, Sara, I think that most of them would be familiar with lysine, methionine, threonine because they're going to see those maybe in a guaranteed analysis or on a feed tag. But just give us a couple of the conditionally indispensable and the ones that they can make themselves.

 

Dr. Sara Mastellar (09:17):

Yeah, so we maybe don't know as much about the conditionally indispensable amino acids in horses specifically. So, we kind of extrapolate from other animals. So, arginine would be an example of a conditionally indispensable amino acid there. And in horse research, we still need to know the amino acid requirements for the essential ones. So, , so I think they're a little bit on the back burner is the understanding a little bit more about the conditionally indispensable ones.

 

Dr. Cubitt (09:46):

And what would be one of those amino acids that the horse can create themselves under the right conditions?

 

Dr. Sara Mastellar (09:53):

Yeah, so arginine would be one.

 

Katy Starr (09:55):

And when you say under the right conditions, is that just meaning that they're getting fed like a really well-balanced diet then, what does that mean?

 

Dr. Sara Mastellar (10:04):

Yeah, so amino acids are made up of carbon and nitrogen and then some of them have sulfur and selenium. So, they have to have those ingredients to do that. And usually, the horse is making conditionally indispensable amino acids from other amino acids. So, , you have to have enough nitrogen in the diet. So, when we talk about crude protein, crude protein is nitrogen, you have to have enough of that in the diet and usually in the form of a, of another amino acid to help with that. Usually, we're not too terribly worried about making sure that we have those ingredients. Yeah. The ingredients to make other amino acids.

 

Katy Starr (10:43):

Right, okay. And so, you're talking about taking, you took blood samples to be able to measure the amino acids, correct? Yep. And so, another aspect of this was measuring muscle atrophy. Can you talk a little bit about that and more specifically what that is as well for those that aren't as familiar with that terminology?

 

Dr. Sara Mastellar (11:08):

Yeah, so I think the, the key thing for, for the horse owner is you have to look at your horse's body and see change over time. So, we talk about body condition scoring and that's fat cover and tracking that over time. So, the muscle atrophy scoring system is a system that's, it's fairly new, came out of the University of Kentucky and Alisa Herbst her work down there. So, what you do to measure that is you classify the horses either adipose or fat or lean and then you look at different areas, body areas and evaluate the muscle in those areas. So, those body areas are the neck, abdomen, back and hind. And then based on your evaluation, you put down like a number. I have a fact sheet, so, if you want to get the chart, you can take a look and then as you're evaluating your horse, put some scores on that.

 

Dr. Sara Mastellar (12:02):

And I guess I would say for the average horse owner, it's not necessary that you get the score exactly correct. You want to be able to notice those changes over time. Why we were interested in muscle mass in this particular study is I think the amount of fat cover and the amount of muscle and how those tissues are proportioned in the horse can impact metabolism. So, we wanted to have those measurements to then contextualize what we got for our results. I would love to see more researchers reporting those measurements so we can make better informed decisions about our horses because we have, they're so, they're so variable, right? So, like you got quarter horses with a lot of muscle and thoroughbreds with a lot of muscle compared to fat and then they thriftier breeds like Morgans and ponies and understanding I think some of the underlying metabolism as it relates to what they have for tissue is important. So, we're not there yet for sure . Right. But taking baby steps.

 

Dr. Cubitt (13:01):

Yeah, I think that's really important too. A lot of people have older horses that may be suffering from different disorders, and I often recommend taking photographs because it's so hard when you see them every day. Yeah. To notice whether they've changed. And they're saying to me, you know, all of a sudden, my horses got no top line. But really maybe it's been more of a progression. Maybe it's something with aging, maybe it's a metabolic disorder. So, I think that that's a, a great new tool. Mm-Hmm . I'm curious how people differentiate between fat and muscle.

 

Dr. Sara Mastellar (13:38):

Yeah, so I think putting your hands on the horse is a really important piece of this. And when I teach body condition scoring, I find an example horse that's got a really nice fat pad and can feel the sponginess of that fat. And then I ask them to feel other parts of the horse, which are, are more muscle. And you can feel some of that difference and some of that you can actually see changes over time and in your training program, saddle fit, all of those also impact your muscle and what you might see.

 

Dr. Cubitt (14:07):

When I give presentations, I never use anybody else as a diagram, but I use myself and I say if you bend your knees and you feel the muscles in your quads, that's what muscles feel like. And then if you squeeze your butt cheeks, that's what spongy fat feels like.

 

Katy Starr (14:21):

 

Dr. Cubitt (14:24):

And always gets a rise out of the audience.

 

Katy Starr (14:25):

. That's a good way to look at it.

 

Dr. Sara Mastellar (14:27):

Yeah. Handy example.

 

Dr. Cubitt (14:31):

 

Katy Starr (14:32):

And I will make sure that we include your fact sheet on that in our show notes so our listeners can reference that if they would like to. And I think it's one of those things where when it's something that's unfamiliar, it just takes a little bit of practice to kind of get the hang of what you're doing. And I think if you are at a point where you feel like you can work with your veterinarian, they can kind of help you get that figured out as well. So, then as you're moving forward, you kind of are able to make those observations as well.

 

Dr. Cubitt (15:04):

It's also a bit of an extension from the cresty neck scoring system. And that was one of the things when we first developed that and first brought it out, it's like, okay, is it fat on the crest or is it we've got a dressage horse or a stallion that's heavily muscled and people slowly worked it out though. But as you said, all of these are a guide and mm-hmm . It's a good place to start. Yeah.

 

Katy Starr (15:24):

Yeah.

 

Dr. Sara Mastellar (15:24):

Cresty neck scoring's also on that fact sheet. So, you have all in one place, .

 

Katy Starr (15:28):

That's awesome. And one thing that I was going to actually ask you before, and I forgot, so when you were doing this study, what was the duration of the time period that you had the horses that you were looking at? Because you said that they each, you know, did the one time, two time, three times. Like what was the time length through the, the whole process of this study and how it was broken up?

 

Dr. Sara Mastellar (15:49):

Yeah, so there was the two weeks of adaptation and then three weeks of one treatment each after that. So, five weeks total.

 

Katy Starr (15:58):

Excellent. Okay. And so kind of as you mentioned we've talked about, right, we often tend to focus on what we're feeding our horses, which is good, but your research highlights that how we feed our horses is just as important. So, can you talk to us a little bit more about how meal frequency influences amino acid availability and why that matters for horse health?

 

Dr. Sara Mastellar (16:21):

Yeah, so I think the results of this study do point to that maybe increased meal frequency could make amino acids more bioavailable from protein bound sources. So, if that is, so it could maybe support body functions that require amino acids, including protein synthesis. Protein synthesis is really important in muscle hypertrophy, right? So, as you're building muscle, but also growth and healing. So, there's some other areas that it could also support if this is truly the case and in some other species, we are seeing that increase meal frequency does help with or has shown increased protein digestibility. So, maybe using that better.

 

Dr. Cubitt (17:09):

I'd love to go back, I don't know whether I missed it or we didn't mention it. The total amount of food consumed in a day in pounds, hay in grain combined was...

 

Dr. Sara Mastellar (17:20):

Yeah. So, we fed 2% of

 

Dr. Cubitt (17:22):

Body weight, body

 

Dr. Sara Mastellar (17:23):

Weight. Okay.

 

Dr. Cubitt (17:24):

Yeah. And so, it didn't matter whether that was one time a day, it was 2% given once, twice a day it was split up evenly or three times mm-hmm . So, throughout the day they were getting the same amount of food, which makes a lot of sense. If we think that the horse is designed to be a grazing animal and to be a trickle feeder and to be constantly digesting food, do we think that it's a function of increasing the efficiency of digestion and that is allowing us to have, you know, more amino acid bioavailability to the horse.

 

Dr. Sara Mastellar (18:00):

Yeah. So, I guess a little bit of a clarification is that we only fed 0.45% body weight of the, of the pelleted feed, and then 1.55% in the hay. So, total 2%. And we fed the hay in slow feed nets, so they did have to take some time to then get through that. All that, the amino acid response in the blood plasma, that's probably mostly driven by the pelleted feed. So, what I think is happening and more research needs to be done as always, is we're dealing with a passage rate, right? And essentially the horse's capacity to dismantle that protein into amino acids and dipeptides so that it can be absorbed, right? So, the bigger that meal is, right? And you only have the same amount of hydrochloric acid and enzymes to work on it. Right? So, I'm wondering if we've essentially overloaded that process and therefore, they don't get the entire protein or the entire meal of protein absorbed, especially in the once-a-day treatment.

 

Dr. Cubitt (19:10):

So, I'm terrible and I don't want to do the math in my head, but tell our listeners one time a day, how much actual of the grain concentrate in pounds was it?

 

Dr. Sara Mastellar (19:19):

When we were doing the study design, we aimed to not have anybody eat more than six pounds in one feeding because that was a concern of ours is we didn't want to be above those five pounds.

 

Dr. Cubitt (19:30):

We're looking in the four-and-a-half to five-and-a-half-pound half pound rate depending on the size of the horse. So, yeah, we're still at the upper end of that pushing efficiency, we'd use that as a guide. And all horses are so different. So, I feel like some people come to me and say, I've got a horse, I'm feeding him four and a half pounds once a day and he's gaining, and he is doing fantastic. And another person, it's like I feel like I'm feeding the same feed, but it's going through him, and he is not gaining at all. So, some horses respond to a bigger meal, and they do fine and others I need to take that four-and-a-half pounds and I split it into three meals, and he does better.

 

Dr. Sara Mastellar (20:11):

Yeah. And we need to figure out why, right? . Yeah.

 

Dr. Cubitt (20:14):

Yeah. If we had another whole day to talk, I would say microbiome all the way, it's the bugs. Yeah. I mean I feel like I even read somewhere when I was putting together a presentation on microbiome that some horses that don't develop that just struggle with the top line. Mm-Hmm . And you know, with throwing protein at most horses left, right and center, they're getting way more protein than they ever need. Mm-Hmm . But then companies are still like, oh, we need more protein. It's a protein supplement that there are microbes that are digesting protein and that if those microbes are deficient mm-hmm then maybe that's a cause they can only do so much, but who knows? I mean there's so many things that go into it, but if we had a magic ball, yeah.

 

Dr. Sara Mastellar (20:58):

One of the limitations of this study is I didn't measure nitrogen in the feces or urine, right? ,it would be nice to see like what the impact was.

 

Dr. Cubitt (21:08):

Excretion. Because if you're feeding the same amount of protein in a day mm-hmm . Ultimately no horse owner wants to tell you that money is an option, but it is always the bottom line, you know? And so, if I tell some people, if you feed once a day that not only is not great for your horse, but you're wasting your money, right? Mm-Hmm . You've got protein going out in the manure pile. Mm-Hmm . I can tell you to spend the same amount of money on feed but feed it three times a day mm-hmm . And you're going to get more bang for your buck. Mm-Hmm. I would bet my house that you are going to get more bang for your buck even without the research. It's always great to have the research to back it up.

 

Dr. Sara Mastellar (21:48):

Yeah. I think there's some other studies out there that would also support that. Like higher growth rate, more protein digestibility, more energy digestibility in more meals.

 

Dr. Cubitt (21:58):

I think going back to even some of Patty's early work, Patty Graham-Thiers had some of that.

 

Katy Starr (22:05):

What would you say were maybe the most surprising or impactful findings from your study on meal frequency and amino acid levels?

 

Dr. Sara Mastellar (22:15):

Yeah, so I expected that the bigger the pelleted meal, the greater rise we would see in the plasma amino acids in the blood after that meal. So, to have each treatment and so each meal size almost creates the same exact response. That was actually I think a pretty cool finding.

 

Katy Starr (22:38):

And I can't remember if you mentioned this already, but when you took those sample, how long was it after they consumed their meal?

 

Dr. Sara Mastellar (22:47):

We did some before. So, we had baseline. And then we did, so we did 0, 30, 60, 90 and 180. So, we were looking at within those first three hours.

 

Dr. Cubitt (23:01):

I'm looking at a picture here. So, just another thing to clarify, were the horses in stalls when they were going through this, or they were out in the field?

 

Dr. Sara Mastellar (23:10):

Yeah, so we kept them on dry lots for most of the treatment and then we brought them in toward the end of the, the period so that way we could do 24-hour video recording of them with the foaling cameras. And then we did the, the catheterization at the end. So, that putting catheters in them wouldn't affect our behavior measurements.

 

Katy Starr (23:32):

You've talked about how just some of the observations and findings have kind of led you to believe that at least three feedings can be very beneficial. So, we also know like owning a horse, you know, there's a lot of restrictions around that sometimes. So, how can horse owners balance, you know, what this recommendation is with some of their real-world constraints that they experience with busy schedules or if they're in boarding situations?

 

Dr. Sara Mastellar (24:02):

Yeah, so translation of the research is always a a challenge, right? When, when the rubber meets the road and reality hits. So, I think Dr. Cubitt alluded to this a little bit earlier is that for some horses it might not matter as much. And if you think about like what your intent is with their horse, like what is their job, what are they doing, what are their needs, maybe it's not worth it to do an extra feeding if it's going to be hugely inconvenient or super costly. Some barns do feed lunch hay, so it's not that much of a, of an issue to then also provide some of your complimentary feed at that time as well. They do have auto feeders and there's some research on those as well. But one thing we did use in our study was nose bags. So, we eliminated the whole ‘bring each horse into their individual stall.’ Instead, we strapped their pre weighed individual meal Okay. Onto their face and then they couldn't steal it from their neighbors. And that seemed to work fairly well as far as like a labor-saving way to do this.

 

Dr. Cubitt (25:09):

Yeah, I definitely would say you going out on limb and say, you know, an adult horse that is not eating large quantities of grain because we're not trying to gain weight, we're not trying to maintain very high performance versus a growing horse or a senior horse when you know, we are increasing the protein requirements in the growing horse and the calorie requirement. And then in the senior horse we know that everything, it just is a little less efficient. So, anything external that we can do to help with that efficiency would be beneficial.

 

Katy Starr (25:43):

And Dr. Mastellar, so were there specific amino acids that showed the most variation with meal frequency compared to others? How do you think this might affect feeding strategies for different types of horses?

 

Dr. Sara Mastellar (25:59):

Yeah, so the responses we saw were pretty similar across individual amino acids. So, that's why we grouped them into the categories. And I think it has to do with the fact that they were part of a protein, right? So, we were going to see fairly as the protein got digested, we we'd hope to see fairly similar responses as they appear in the blood.

 

Katy Starr (26:21):

And your study looked at horses with different body condition scores. So, you said that that kind of, once you kind of weeded out some of those ones that had some of those disease issues, you didn't have the variation that I think you were hoping to with that. But how does a horse's fat or muscle stores impact their ability to utilize the amino acids?

 

Dr. Sara Mastellar (26:45):

Yeah, I don't think we know enough about this yet. And that's actually why , why I wanted a variety of, of body condition scores to basically understand normal metabolism in healthy horses of varying body conditions and types. Sometimes there's some studies that have looked at amino acid profiles, but they've got horses, or they don't report body condition scores. Part of the problem is some of, there's some of those and I don't know that we know enough about what's normal to know what's the disease how that's influencing the, the plasma amino acids and what the body composition is and how that's influencing the plasma amino acids. So, definitely lots of more research to be done in that particular area.

 

Katy Starr (27:34):

Okay.

 

Dr. Sara Mastellar (27:34):

And now that we have a muscle scoring system, hopefully more people will use it.

 

Dr. Cubitt (27:40):

Earlier we were talking about stress response in horses and that's why I was curious whether they were in stalls or outside. And it really seems like to control a lot of variability, you decrease stress by keeping them out, by putting the feed bags on, you really didn't change a lot in their day-to-day life, which can kind of take that variable out of it. So, you're just measuring the feed, the timing and the number of times that you fed them. And it's not, nothing else is affecting it. But I am curious because our horses do live in a lot of stress and there is some thought that when an animal or a person is stressed, you know, especially in a fight or flight animal, they've got to quickly get energy. And I'm wondering, you know, is some of that energy from quickly breaking down protein in a wild horse?

 

Dr. Cubitt (28:29):

They are in very acute short-term stress, so it really wouldn't be a problem. But our horses are under long term chronic stress and a lot of those horses, whether it be stress from the environment that they're living in, stress from inflammation, stress from disease, is that affecting protein metabolism? I know we're getting away from the topic of protein and, but you by default through Dr. Urschel, I will refer to as the queen of all things protein. So, I'm curious because a lot of these horses also have, you know, the outward symptom that horse owners would say to me, my horse doesn't have a great top line. And then we're grasping at straws because the client is doing the right exercise, they're feeding enough adequate protein, but there's still a missing link. Is it because the horse is just getting older and everything is harder? Is there a disease state or is it that these horses are under just chronic stress and that is affecting protein? I know it's not what we were talking about today, but I think it's super interesting.

 

Dr. Sara Mastellar (29:36):

Yeah. So, there's a lot of pieces to answer in that question. I guess I'll start with meal frequency and stress because one of the other things that we did measure was heart rate. So, we put heart rate monitors on these horses for 12 hours. So, we actually encompassed all three meals. And what we did see is the ones that were fed once a day tended to have a higher heart rate across the 12 hours, which I think was really interesting to me. So, is, is that indicating that there's stress? I think that there's certainly something to that. So, can how we feed impact stress? Yes. Do we know how stress affects protein metabolism? I don't think we're there yet. , but yeah, I know those poor doers, right? They just, there's activity level differences, right? When they're stressed. And then age, age is a, a big thing.

 

Dr. Sara Mastellar (30:30):

So, in writing my dissertation, I actually looked at protein synthesis levels and I collected a bunch of different studies and then put them all in one graph. So, when the horse is young, the rates of protein synthesis are really high and then you can see this downward trend and almost a plateau after they're mature. And so those old horses, you can actually see that it's a lot harder for them to maintain that protein. So, it really matched the kind of physiology we see with age-related muscle wasting. So, keeping that exercise and managing all the pieces right. And also, how you feed back to how you feed horses are eating that forage for so many hours a day and I think there's some research out there now on different feeders, hay feeders. So, how does that affect their posture? You're asking them to stand in a particular posture for hours on end because that's what they do right. With their time as they eat. And actually, why I wanted to study this is because we can impact their lives so much because they spend so much time eating. Right?

 

Dr. Cubitt (31:35):

Yeah. And I think that there are just so many things in our horses' lives that are out of our control. Where obviously if you're going to a show, you're putting them on a trailer, you're stressing them, you're putting them in stalls, you're stressing them, you're riding them because that's what we want to do with them. So, if there are so many stresses that we can't take away, I really try to focus on the things that people can control. And obviously we talk about the types of ingredients that we're feeding horses, but I also, that's why I was so excited about you talking today because I do talk a lot about, it's not just what you're feeding them, it's how you're feeding them. I always love that research will back up the things that we're encouraging people to do. Because these are simple things that don't cost money well directly. No, it's not costing extra money. Indirectly, yes it's costing extra money because it's a labor thing, but it's simple to do. Like you said earlier, I'm not really asking you to buy anything different, buy a different feed. I'm not asking you to change your feed. I'm just simply asking you to manage it differently. And that's something that every owner can take control of. Hopefully. Now obviously then you jump into the whole, well I board my horse, and the barn manager says we do it this way or you got to go. So, that's hard too, but.

 

Katy Starr (32:48):

Well, and I think if you're able, in a perfect world, right, we would probably want them to feed three times a day. But if you're not able to, feeding twice a day is obviously better than one time a day. So, I think when you're looking at everybody's situation and what works best for you, do the best that you can, but do your best to make improvements as you can as well.

 

Dr. Sara Mastellar (33:08):

Yeah. And I guess if we're designing our perfect world, right? Is it six? We don't even know. I picked

 

Katy Starr (33:13):

1, 2, 3. What is the perfect world? ?

 

Dr. Sara Mastellar (33:16):

I picked one, two and three because they're fairly common. Actually, we did a, a survey and shout out to Liz Share because this is part of her dissertation work. So, and a teaser for something that's going to be presented at Equine Science Society meeting this summer. But a fairly large portion of the Ohio horse owners and managers only feed once a day. Really? And the concentrate. Yeah, I was, I was like, oh, that's

 

Dr. Cubitt (33:41):

. Did the survey also ask how much quantity? Because I would go out on a limb and say that there are probably a lot of people that are feeding ration balancer. At one pound a day, which in context sure. Feed it once a day. But it'd be interesting. What were they feeding once a day? Were they?

 

Dr. Sara Mastellar (34:00):

Yeah, I think that's a a great question too. And ration balancers tend to be high in protein. And maybe if we were feeding it once a day though, it's not all that bioavailable. So, splitting up your ration balancer probably has some benefits. So,

 

Katy Starr (34:17):

And so you talked a little bit before about if you had the chance, you know, to do this study again, some of the limitations of what you experienced doing this research, I think measuring the nitrogen and the manure and everything. Is there anything else after you've gone through this that if you had the chance to do it over again, is there anything else you would change? Is there anything else you would add besides that?

 

Dr. Sara Mastellar (34:42):

Yeah, so I think there's always more questions and that maybe that's that's a good thing, right?

 

Katy Starr (34:50):

That come up. You're trying to answer questions. Yeah. And then you're like, wait, now I have more questions from trying to get these questions answered.

 

Dr. Sara Mastellar (34:55):

Yeah, exactly. Yeah. So, for this specific study, I, I think one thing that we, we didn't measure but would've been a really neat thing to measure would be microbiome, but also microbiome changes throughout the day, right? So, when you're giving a meal, you're essentially giving a bolus of whatever that meal is, as opposed to if you feed, if it's just forage and they're eating that throughout the day, it's a very steady stream of those nutrients that are feeding that microbiome. Whereas you're doing a meal, you have this big increase right? In certain nutrients. And I think there's potential that that impacts the microbiome. We probably should know about that. So, yeah, that would be one for sure. It would've been really interesting to test some smaller meals because I would like to get below that maximal, I guess response in plasma and blood plasma amino acids, right?

 

Dr. Sara Mastellar (35:54):

So how low can you get like where is that threshold? Are we above it for all three? Is there a threshold? Right? So, there's lots of things to do with, with meal size I think and protein digestibility, amino acid and bioavailability. And then in this study it was looking at just protein bound amino acids, right? So, in other research trials we fed crystalline amino acids for specific purposes, and you do see a dose response with that. So, if you are more crystalline lysine, you see more of that in the blood. So, which is makes a lot of sense and that's why, or part of why I was really surprised that we don't see that same dose response for these meals.

 

Katy Starr (36:37):

Obviously talking about some things that you would do differently from here, what are next steps? I mean I know that there's questions upon questions that came from this. Yeah. But what would be the next direction that you think would be a good focus to keep progressing forward from this study?

 

Dr. Cubitt (36:54):

Pretend you've got all the money in the world , that's not an option.

 

Katy Starr (36:58):

Because you know how that works. Yeah, yeah,

 

Dr. Sara Mastellar (37:00):

Yeah. I'm still working on getting all of the things we measured this time around analyzed and published and all the things. But yeah, I think it would be really interesting to look at different meal sizes starting really small and working up and then also different protein types and then the same ratio of amino acids in crystalline amino acids, right? So, protein bound versus free amino acids. So, I think there's a lot to learn about protein digestibility and, and bioavailability and then also amino acid requirements, right? So, , I didn't quite get that solved during my PhD. And I think as we learn more about the horse, maybe we can re attempt that. If I had all the money in the world and the time, right?

 

Katy Starr (37:50):

Time and money . Yeah, for sure.

 

Dr. Cubitt (37:54):

So again, I just want to clarify one thing you, you mentioned again for our listeners, free amino acids versus protein bound amino acids. Are you meaning, you know, I'm adding soybean meal, and it's got a certain amount of crude protein in it and the lysine that is in there and the methionine and threonine is bound versus me adding pure lysine or tell our listeners what you're meaning there by protein connected versus free amino acids?

 

Dr. Sara Mastellar (38:20):

Yeah, so the common analogy is a Lego set, right? So, a protein bound amino acid would be one that's part of a prebuilt Lego set, right? Whereas free amino acid is just a single, single piece or a set of the single pieces.

 

Dr. Cubitt (38:34):

And how might they see that in their horse's diet though?

 

Dr. Sara Mastellar (38:38):

Yeah, so if you look at the feed tag, usually they have listed those crystalline amino acids. So, the ones you're likely to see lysine, threonine, methionine, tryptophan, we see some of that.

 

Dr. Cubitt (38:49):

We're individually adding those to the feed. Yes. Versus the amino acids that are coming as part of the protein that is in the other ingredients. Individually adding those to the feed. Yes. Versus the amino acids that are coming as part of the protein that is in the other ingredients.

 

Dr. Sara Mastellar (38:58):

Correct. Yep.

 

Katy Starr (39:00):

Okay. So, as we wrap this episode up, what would be some of your key takeaways that you would like to leave our listeners with about the impact of how often horses are fed?

 

Dr. Sara Mastellar (39:13):

Yeah, I think meal frequency is a tool and one of the tools we have in, in horse management. And you should use that tool to the best of your ability to support maximum horse welfare, wellbeing, health, all of that. And then monitoring your horse, right? So, taking those body measurements and seeing how they change over time to your management, whether that's meal frequency, turnout schedule, riding, your conditioning plan. There's so much that gets reflected there. And I think observation is really central to good horsemanship and all of that.

 

Katy Starr (39:53):

Excellent. Dr. Cubitt, is there anything else based off of our conversation today that you'd like to add to that?

 

Dr. Cubitt (39:58):

No, I, I think it's great. I think it's always great to have science to back up the things that we talk about with our listeners about management of feeding schedule. That it's not just the feed you're feeding, but it's how you're feeding it as well. Would you say just another little side note that horses' lives change and they might even just change within a year and maybe you have a race horse and it's high performance and it's getting fed 3, 4, 5 times a day even and then it goes on layup, do you think and he's getting less food, maybe more forage-based, less concentrate feed, that horse owners should be flexible as well with changing based on how the horse changes or you've got a performance mare that now becomes a broodmare and she's getting a different diet and the whole management is different. So, now she's getting fed twice a day versus four times a day. I think that not only is it look at your horse, but your horse changes and don't be afraid to change your horse's management based on what they're doing at that time. Just because you did it like that when they were three doesn't mean you do it like that when they're 15.

 

Dr. Sara Mastellar (41:08):

Yeah. It's getting that feedback from the horse and then making adjustments.

 

Dr. Cubitt (41:12):

Yeah.

 

Dr. Sara Mastellar (41:13):

To help them.

 

Dr. Cubitt (41:14):

One of my funny sayings is horses talk a lot. They tell us a lot. We don't always listen. Yeah.

 

Katy Starr (41:20):

And there's a lot of truth to that. I think after listening to the conversation today. I mean obviously both of you have your doctorates and so you have this understanding of the science, I think more than some others. My takeaway as we were talking through this that I think hopefully will be really helpful for horse owners as well is just the impact if they are able to kind of, rather than having just the one time a day or two times a day, if they could fix the management to work out to three times a day or, or however that lays the fact that they're able to, the horse is able to kind of absorb those proteins and amino acids just a little bit better and ultimately save money. I think anytime we have these conversations, a high thing on the list is they just cost a lot of money.

 

Katy Starr (42:10):

It costs a lot of money to own horses. And so, when we're kind of working through what are things that we can do with feeding management, any of that, that can allow us to just be more efficient with, you know, how that's done in my mind, that's just really kind of stuck out to me. And so, I'm hoping that our listeners kind of take that away as if they're able to make this work. They potentially could be saving themselves some money on that end because the, the horses are going to be utilizing that feed a little better than they would be otherwise.

 

Dr. Sara Mastellar (42:38):

Yeah. A lot of the other livestock species talk about feed efficiency rates, . Right?

 

Katy Starr (42:42):

Right. And that, that matters more to them because it's always in a production conversation, right? With horses it's a little bit different, but it can still help you. And so yeah. Yeah, I just found that to be interesting. So, Dr. Mastellar, lastly, how can our listeners stay connected with you after this episode?

 

Dr. Sara Mastellar (43:01):

Yeah, so I have a university profile page. It's got my email and, and phone number on there. So, my email is mastellar.1@osu.edu. I'm the one and only Mastellar because that's how they assign email addresses . So, yeah, you can find me there and we have a Facebook page. The ATI Equine Center has a Facebook page, and you can follow along with what the students do and what they learn in our program here. So, those would be the two main ways.

 

Katy Starr (43:31):

Excellent. I'll make sure I include those in our show notes for listeners to have easy access to that. And to our listeners, thanks for tuning in today. If you guys have any topic ideas that you would like us to cover on the Beyond the Barn podcast, please reach out to us, give us feedback, let us know. You can reach me at podcast@standlee.com. And other than that, Dr. Mastellar and Dr. Cubitt, thanks for joining us today. It was a great conversation. Thank you.

 

Dr. Sara Mastellar (43:58):

Thanks.

 

Katy Starr (44:00):

Thanks for listening to The Beyond the Barn podcast by Standlee Forage. We'd love for you to share our podcast with your favorite people and subscribe on Apple, Spotify, or your favorite listening platform. Until next time, keep your cinch tight and don't forget to turn off the water.