Dietary Fiber for Horses: It's not Grandma's Metamucil!

- [Danielle] So our speaker today is Dr. Burt Staniar.

He is here at the Penn State University Department of Animal Science, he is an equine nutritionist and he'll be talking today about dietary fiber for horses, so with that, Dr. Staniar, go ahead.

- All right, thank you Dr. Smarsh.

It is my pleasure to be here, and I'm looking forward to giving this talk.

This is a topic that I am particularly interested in right now.

A lot of the work that we're doing here at Penn State and some of the research that we're doing is trying to get a better understanding of dietary fiber, so I think that this is something that most horse owners will hear about and I hope to help you all kind of understand what it is we're thinking about and I kind of want to get a feel for what you think as well, so we'll start to see some of this as we're going forward.

Dr. Smarsh, I think we're gonna go ahead, I've got a number of questions that I'm gonna try to engage those who are participating today throughout the presentation, so why don't we go ahead and put the first question up and let's see if everybody can participate a little bit.

Awesome, so here we have the result of this.

Do you think your horse is getting enough fiber in its diet?

And, so this is interesting right?

So we've got about a little less than half of you think that your horse is getting enough fiber, there's one person that doesn't, and this is good, we've got four people that are gonna learn something today, so maybe they are.

And two that have no idea, so actually probably up that to about six of us that are going to potentially learn something today or at least come with some more knowledge, so that's excellent.

I don't know whether I need to close this, or you wanna go ahead and we'll do one more question as we start things here,.

So we've got another introductory question here.

All right.

So this isn't thinking about dietary fiber as an energy source, and again, we can see that most of you guys are up at the very important, to important, and moderate importance, so nobody is down in the slightly important or not important.

I think that a, leave the results up here for a second, I think that a key component to this question is thinking about fiber as an energy source.

What we'll talk about, is there's a lot of different things that fiber does, but I want you guys thinking about why it might be important as an energy source as well.

All right, so if we go ahead and put that down, we'll get to my slides here, and just in case anyone isn't aware, caught a little bit of guff for our answer here, Metamucil, metamucil is usually one of the things that people think about for people in regard to fiber in their diet, and I've put a picture up here of the cilium husks that are the primary ingredient in Metamucil.

Metamucil is a fiber source and that fiber source is made up of the husks of a plant material that has some of the important characteristics of fiber for humans, so it does help with gut health some, one of the primary things that Metamucil does is actually to enhance the mucus protection layer that's inside our gastrointestinal tracts.

So the second picture I put up here is a very important equine feed ingredient, one of my favorite sources of fiber in the equine diet, and that's beet pulp, so beet pulp, for reasons that we'll talk about, is an excellent source of fiber.

There are many sources of fiber in the equine diet, but that happens to be one of them, and I think the two of those are similar in many ways and how they kind of get utilized in the diet.

So first of all, we need to think a little bit about the horse, we need to know a little bit of the background of the horse and so I've put a picture here, this is a picture of the Gobi Desert in Mongolia, some of you will be familiar that that happens to be one place where horses do very well, also all kinds of grazing animals do well there.

The reason that those animals do well in what is a relatively harsh environment, we can see that it is a desert, is that there are actually vast grasslands there, so there's a lot of grass that grows in that region, at some times there's more of it than others, but this is really an environment that horses are well adapted to, of course they can travel out across those grasslands very well and the key here is that grass.

That grass is an important part of their diet, and if we think, you know this might be a picture that is more familiar some of you as far as kind of a North American grasslands environment, particularly here in Pennsylvania, I took this picture in Virginia, so the grassland environment that's there, certainly not quite the same as the grassland environment that we might see out West.

One of the things that we do know from a scientific perspective, is that horse have evolved over the last, it's about somewhere between 60 and 40 million years and for about 40 to 30 million of those year, they've been eating grasses.

They have become very well adapted to eating grass, that's what the horse, that's what they're good at, that is, you know, everything about their body, yeah, they might be good at being athletes as well, but everything about their body is about eating grass, they eat grass and they reproduce, that's what most animals in the wild do.

And we happen to take advantage of the fact that they're particularly good athletes.

So as we think about feeding this animal, a large portion of that grass that they eat is fiber, okay?

And so that fiber for a horse, when we talk about its maintenance energy requirements, that fiber is very important as an energy source, so it is one of the primary sources of energy, and I find, I'm glad to see that those that are participating in this, realize that fiber is an important energy source, but many horse owners, if you talk to them about what are the important energy sources in their horses' diet, they're gonna typically think of the grains or the concentrates that they feed first.

Those are important, but those are important for the additional energy that's required for the exercise that we use them for, not so much for those maintenance energy requirements.

So this is one of my favorite figures out of a paper by Christine Janis who I believe is at Brown University now, this is from an older paper of hers from 1976, where she really looks at a comparison between horses and cows, and the different diets they eat.

For those that don't really know, you might look out into a field and see horses and cows eating the same diet together and think, well they all eat grass, they all do the same thing, they're similar to one another, they're actually quiet different from one another and they eat in different ways, depending on the plant material that's available.

So one of the things that this picture shows, and I think you can see my cursor here that I'm using, is that in a period of time, if we talk about the spring, where there's really fresh digestible rich forage that's available, so this is young plants that are available, the cow and the horse are both eating that, they do relatively well on it, you can see that the horse is eating a little bit more, that's why it's got a little bit bigger arrow, little bit less with the cow, so the intake of the horse is more, and their rate of passage, this arrow's a little bit bigger than this arrow, so they're going a little bit faster, and they make lots of poop, little bit less than the cow, okay?

And so this really has to do with the fiber that they're eating.

It's also been shown that horses will actually choose more of the stem and leaf material, whereas cows will often choose the leaf material of the grasses that they're eating.

An important component of this is that the efficiency at cellulose digestion in a horse is 70% that of the ruminant.

That means the horse is less efficient at digesting that fiber than the cow.

That becomes an advantage in the lower portion of this picture here, so again, really a lot of Christine Janis's work is looking at wild animals and oftentimes she'll talk about some of the work done with, out on the African savannas, looking at zebras and water buffalo and wildebeest and that sort of thing, and in those circumstances, the ruminants, the cows here, when the plants have become mature, let's say it's during the middle of the summer, drought conditions, now the plants are very mature, there's lots of fiber that available now, the non-ruminant herbivores, like the horse, the hindgut fermentors, actually do pretty well on that poor quality forage and all that fiber, because they can eat a lot of it and it moves through their gastrointestinal tract pretty quickly, so they've got a high intake and a high rate of passage.

Cows, because they have that large rumen, it fills up with all of that fiber and they can't eat anymore, so the cows and ruminants actually need to move to higher quality pastures before the horses do.

Horses are very well adapted at eating a high-fiber diet, okay?

So I wanna go ahead and bring up our next question here, we've got question three.

Are horse hay burners?

Yes they are, excellent, you guys are paying attention, so two of you maybe have some questions about this, right?

Why are horses hay burners?

I always laugh at this, because again, people that don't like horses very much, are like, "Ah, I don't like horses, "they're just hay burners", right?

The fact of the matter is, horses are hay burners, they're very inefficient at digesting forages, but that's how they adapted to living on the planet earth, that was actually an advantage to them, because there was always plenty of grass available, so one evolutionary approach, is just eat lots of that fiber and just not digest it very well.

So in reality, horses really are hay burners, they produce a lot of feces, those of us that clean out stalls know that, right?

They produce a lot of poop, a lot for us to clean up.

All right, let's go ahead and keep going.

I'll just see if this goes to the next one.

All right, so as we think about fiber, you also have to think about the anatomy of the horses' gastrointestinal tract, and so as we look at this, if we look at the horses' mouth structure, as we look at their stomach structure, as we look at their entire gastrointestinal tract, this is really an entire fuel intake system that is very well adapted to fiber.

We can break down that fiber in the mouth, we can bring it into the stomach which is separated into two regions, one where the longer fiber can kind of sit up on top, and the smaller fiber can go down to the bottom and be digested, and then all of that, both combinations of long and short fiber, can move out.

Notice how the exit into the small intestine is about halfway up in the stomach actually, it's not down here at the bottom, things don't come in at the top and exit at the bottom, they come in about, you know, 1/3 of the way down, and they exit about 2/3 of the way down, okay?

So it's kind of interesting to think about that.

We've a very complex hindgut that relates to the horses' ability to digest fiber.

So if we talk about fiber, you don't need to know all of this, but fiber is very complicated, carbohydrates are very complicated, and fiber is just one type of carbohydrate, okay?

So many of you as horse interested people are probably familiar, we've talked a lot about nonstructural carbohydrates, we talk a lot about sugar and starch.

We all do know that fiber is the other half of that, but maybe we don't talk about it enough or know that much about it, okay, and so the fiber components in this picture, you have all the different things that I've shown here, if you send off some hay for analysis, you might get some analysis back that says you've got some acid detergent fiber, or some neutral detergent fiber.

Well, what are those, who knows, right?

The primary components of fiber, if we look at that from a chemical standpoint, are cellulose and hemicellulose, these are molecules, long chain-like molecules that make up those fiber components and are ultimately what end up holding up, they provide the structural components of plants that allow those plants to stand up, okay?

So to try to explain to you a little bit more about what is dietary fiber.

When we talk about fiber, what are we talking about?

One of the confusing and difficult to understand factors here, is that in reality, fiber is oftentimes defined by the way we nutritionists analyze it, okay?

And so what I've put here are two different ways of analyzing dietary fiber.

There is this very old way, the Weende proximate analysis, and when I say very old, this was developed in the 1800s probably, 1700s, 1800s, and that, the end of that analysis, we get lots of different things from that as far as our nutrients go, but the end of that analysis is crude fiber, okay, so we define, in this system crude fiber, and that we get this very crude measurement of that fiber.

I challenge all of you to go out to the barn now and look on your feed tags and see how, here in 2020, we now define fiber.

You will all still find crude fiber on your feed tag.

I will argue, as a nutritionist, that that is a very poor estimate or characterization of our fiber.

It's a matter of us moving forward with some of the science and trying to do things better, but that is a very poor measurement.

Now a newer technique was put together by Dr. Van Soest up at Cornell and then he was at the USDA, and that's this Van Soest proximate analysis, and this allows us a little bit more.

What he sort of says, okay let's analyze these things and we can look at the plant-cell contents and we can look at the plant-cell wall.

And if we're talking about fiber, we gotta focus down here on the plant-cell wall, and we know that the plant-cell wall is made up of other organic material, it's made up of hemicellulose, cellulose, and another molecule called lignin.

These are the primary fiber components, okay?

Hemicellulose, cellulose, and lignin, those are the fiber components, that's what fiber's made up of.

And the way that we analyze those things, is we have analysis we can do in the lab that's either neutral detergent fiber, NDF, acid detergent fiber, ADF, or acid detergent lignin, and what I've done here is to show NDF, if we get neutral detergent fiber, neutral detergent fiber includes hemicellulose, cellulose and lignin.

ADF includes cellulose and lignin and ADL includes just lignin, and so by subtraction from each one of these, we have the capability of determining each of these characteristics, okay.

Now if you go and look that feed tag again, you will probably see NDF, you might see ADF, and I don't think you'll see ADL, okay, so we're moving in the right direction, but I think that as we go forward, the type of analysis you wanna look at is NDF and ADF.

Oftentimes you'll find ADF is similar to crude fiber, okay?

The other thing to know about this is the higher the NDF is, that really relates to the gut-fill, that's gonna really be the fill characteristics of that.

And ADF, that's really more the digestibility of the diet, so the higher the ADF content, the lower the digestibility, the higher the NDF content, which you're gonna do is higher NDF is gonna usually mean lower intake.

So those are some different chemical characteristics of fiber that are important and I hope you can understand a little bit more with this.

Now, chemistry is not the only way of defining fiber, and this, this is totally outside the box, there's a funny joke there but I'm not gonna say it, in regard to thinking about fiber, and that's the physical aspects of fiber, this is something that dairy nutritionists do very well, and dairy nutritionists use this tool right here, this is the Penn State Particle Separator, and what it allows us to do, is to separate particles of different sizes.

As horse owners, we're not thinking about this enough right now, and this is one of the areas that we wanna do some more research here at Penn State, but if we look at the fiber, if we look at the chemical fiber in each of these three piles of food that I've got on the left-hand side here, the chemistry might be exactly the same, so if I go back to this slide, our cellulose, hemicellulose and lignin for those samples might be exactly the same for all three of these, but the physical fiber is gonna be totally different.

I hope you can all see that, that a horse is going to chew the top pile a lot more than it's gonna chew the bottom pile.

So even though you might have a pelleted feed that has a high fiber content, that's chemical fiber, that doesn't necessarily mean it incorporates all the characteristics of the fiber that are important for your horse.

And I hope to illustrate to you that this physically affected fiber is also important for your horse.

One of the ways that we, as horse owners, might think about characterizing that and that's where we need to do some more work, is using a tool like dairy nutritionists do here, this is the Penn State Particle Separator, these are a bunch of boxes, that's what I was referring to earlier, where we can put our food up on top of this first one, and we can shake it down and we can see where do the different particles fall on these screens, and that gives us an idea of the physical nature of the fiber in that diet.

It's relatively qualitative subjective, but at least allows us to measure those to some degree.

So that's an interesting way we might go forward with some things.

All right, so I wanna talk a little bit about all the different things dietary fiber does for your horse.

Some of these you're familiar with, but some of them you might not have thought of before.

So number one, the first thing that dietary fiber does, is it helps your horse to chew, that's important because when the horse chews more, it is producing more saliva, that saliva is important for buffering the acid in the horses' stomach.

The less the horse chews, the less saliva they're producing, and we think that that may be important in our risk of ulcers.

The second thing that fiber does, is it actually, that particularly the physically effective fiber, acts to separate the solid and fluid portions of the diet, and that's illustrated really well here.

Al Merritt was a well-known scientist that did a lot of work with ulcers in horses, and he hypothesized that on a high-fiber, high physically effective fiber, so that longer fiber, that if you looked in the horses' stomach, you would actually see separation of a low density mat at the top of the stomach, a medium density mat and a high density liquid here at the bottom.

So we got kind of the grass, the fiber, floating up on top, and the pH of that is lower, and then as we move down, actually higher, the pH is higher the acidity is lower, and then the acidity is higher down here in the lower regions of the stomach.

This again, may help, not only in reducing the risk of ulcers, but this idea of solid and liquid separation is really important when we think about the risk of colic.

Another thing that fiber does, that's over here, fiber is a really important food for all the microbes that live in your horses' gut, and those are in the small intestine and in the large intestine.

So if you want to feed those microbes, if you want the ultimate prebiotic, it's fiber.

All the fiber that you incorporated, all the different sources of fiber, and that's where you should supply a lot of different types of fiber because that's gonna help to feed all of those different microbes.

And the last thing I list here that fiber also does, is it does help to form, and you know, some of the soluble fibers help to form some of that mucus layer, and that's what I've got down here, mucus layer's protecting, this is meant to represent the gastrointestinal tract, so here we have all these microbes that are out in the lumen of the gastrointestinal tract, they're digesting all the fiber, but we don't want those microbes right up against the intestinal walls, so we want a nice mucus layer that separates those things.

If we don't have a good amount of fiber in the diet, that mucus layer may not function quite as well and we don't get good protection there and we may get damage to the gastrointestinal lining.

So in order to do all of these different important things, it takes putting a lot of different types of fiber into the diet of the horse.

So when I think about my own horse, I think about well, I want some grass hay, maybe a little bit of alfalfa, I wanna make sure there's you know, again, maybe the diet's got some beet pulp in it or some soybean hulls, a lot of different types of fiber and incorporating those all, as a nutritionist, I tend to think of in moderation, so that I'm helping to serve all of these different purposes through my horses' gastrointestinal tract.

And you know, one of the things I didn't mention here that I pointed out in the beginning, is that that fiber is also serving as an energy source for your horse, because these little microbes are breaking it down and turning it into an energy source for your horse.

So one of my reasons in wanting to talk about this and asking Dr. Smarsh if we could do this as a topic for you all, is that I think that if horse owners have a better understanding of the carbohydrates that they're feeding their horse particularly the fiber and begin to think about that a little bit more, we may be able to address some of the major gastrointestinal problems that we see with the horse, we may actually be able to improve the health and welfare of our horses by paying closer attention to the dietary fiber in our horses' diet.

So that does require us, as horse owners, taking some responsibility and learning some of the science.

So if we come down to this picture on the bottom right-hand side here, you can see here the hemicellulose, the cellulose, the lignin and all as a component of this plant, so here we have the grass plant that we all know, but if we look at the cells of that plant, it's got a cell wall, and if we look at what those cell walls are made up of, that's where we get the hemicellulose, the cellulose and the lignin, that's what's making up the cell walls of that plant.

That's where the fiber is coming from.

And it's important for us to think about that a little bit more, how do those change as the plant matures?

We can talk about different maturities of hay.

All right, so this is an important slide, and we'll ask as a question at the end of this slide and start of thinking about this, but this is all about all of the different types of carbohydrates.

So, again, I really appreciate those of you that are here today, that are hoping to learn a little bit more about this, because that fact of the matter is, this is relatively complicated, okay?

And so some terminology that you should know, you should know carbohydrates, okay, so carbohydrates generally, if someone says to you, "Carbohydrates", you should say, "Yeah I know carbohydrates, "there's structural and nonstructural carbohydrates," okay, that's the two broad categories, and those are a major part of all the plants that my horse eats.

What are nonstructural carbohydrates?

We're not talking about those as much today, but the nonstructural carbohydrates are really this sugar and the starch, okay?

So those are a great energy source for our horses, we've got a lot of those in oats and in corn and in barley and in some of the pellets that we feed to our horse, that's fine, but then if we talk about the structural carbohydrates, that's the fiber, that's what we're talking about today.

There are a lot of different terms with that, we've got again, fiber is a very broad term that really, honestly is not very descriptive, because there's so many things that come underneath it.

I've mentioned physically effective fiber here, I would like to see more horse owners thinking about physically effective fiber.

Physically effective fiber is literally the fiber that causes a horse to chew more and also results in that separation of the water and solid components of the gastrointestinal tract, the word that oftentimes gets used is biphasic nature of the gastrointestinal tract.

Any fiber that does that, that's physically effective fiber, okay, and usually it's gonna have a size to it.

Forage, again, we have lots of forages that we feed to horses, and oftentimes those are rich sources of fiber.

Hay is a preserved forage, that's gonna be another source of fiber, and pellets, our pelleted diets or our grain diets, those will also have fiber in them and it can be chemically defined, and it can be physically defined.

And so those are characteristics that we should try to bring together in defining that.

Further, as we talk about our feeds, you might have chaff feeds, you may have also heard of fiber and fat type diets or total mixed rations.

These type of diets are usually both chemical fiber rich, so they've got a lot of fiber in them, and they should have some physically effective fiber, so the picture I'm showing you, they've got some like chopped hay in them.

One of the classic examples are two, I'll give you two, because I'm not selling any feed here, two companies that I'm aware of that make diets like this, are Lucerne Farms or Dengie, some of you may have heard of that, they've got some chopped forage products, and also Triple Crown.

Those are not the only feed companies that produce some chopped forage type products, but that's kind of what we're talking about here.

And then we've got our sweet feeds, those are going to be nonstructurally-rich diets.

The only thing I'll say is we've done some work here at Penn State where whole oats can also be a source of physically effective fiber because of that oat hull and all of the fiber that's present in that.

Oh, we're supposed to have a question there.

All right, let's see what we've got here.

So NDF came out at the top, I don't have a problem with that, that sounds good, it looks like you've picked all of these different things.

And the answers are as I would expect them to be.

So a couple of things I want to address here.

I did not do a good job of telling you guys that fiber fermentation rate is also important, so as you're taking notes, if you're taking notes, the rate of fiber fermentation is important, all of our different fibers can be fermented at different rates and that is another characteristic that would be important but I didn't mention it.

So we can have rapidly fermented fibers, those we usually want a little bit less but there's some of them that are good, and then there's slowly fermented fibers, and we want a whole range of those in the diet.

I would also argue that crude fiber in this case, I'd like less and less people to think that crude fiber is important.

It is a characteristic, it is a way of describing fiber, but it is not particularly useful.

So I would've been happier to see if you've a little bit less choice of that particular one here.

I know it's listed on the feed tag, but it's not particularly valuable in regard to equine diets.

So just think about that as we're going forward.

All right, back to our slides.

So this is a slide that I use in all of my nutrition classes and the reason that I use this slide, is because it talks about all of the different diets that horses get, so this really covers everything.

In the top right-hand corner we can talk about our fresh and preserved forages, in the bottom left-hand corner, we can talk about all of the grains that we provide, oats, barley, corn.

In the top left-hand corner, we talk about the diets that we produce for the horse, so our pelleted diets, some of the different concentrates, and in the bottom right-hand corner, these are my physically effective fiber rich diets, our total mixed rations for horses, or our chopped forages or our chaff.

All of these have fiber in them, and I want you sort of listening to this, to think about your own horses' diet and where is the fiber in your horses' diet.

How are you providing that fiber?

You know, hopefully your horses are probably getting a little bit of all of these different things because that, again, that's everything in moderation, that's where you horse is sort of getting all of those different aspects that I have, but all of these are valuable sources of fiber, you just think, "I have to think about "how they're different from one another", like the preserved forage or hay, okay, is gonna let you horse chew a lot, or a chopped forage is gonna let your horse chew a lot, so that's good, whereas the pelleted diet, that will provide some chemical fiber and maybe some of that chemical fiber that's being presented in the pellets here is useful for the microbes to eat, or for mucus production, and then the grain, that's gonna have a little bit of both, you're gonna have some fiber that's present in the hull, that might be good for some of the microbes and again, it also may cause some chewing, so all of these together are really valuable but think about where the fiber is and how you would characterize the fiber in each of these sources.

So this kind of leads me to the second half of the presentation where we really want to think about how does fiber influence health of the horse.

And I've been studying this for a long time, this is really where my research is focused, because way back when, when I was doing my PhD, we were studying fat and fiber type diets, we were studying these chaff type diets and that's because my PhD advisor was originally a dairy nutritionist.

And then we transitioned a lot of that into thinking about horses, and even here at Penn State I work very closely with a lot of our dairy nutritionists, and they are absolutely, they think physically effective fiber is so important for dairy cow nutrition and in helping those cows to be very healthy, believe it or not, dairy cows get laminitis, dairy cows have acidosis in their gut, and these are all similar problems that we see in the horse, okay?

We're gonna skip over the classroom here but many of the problems that we see in the horse are things like ulcers and inflammation of the small intestine, inflammation of the hindgut, inflammation of the hoof, all associated with the diets that we feed.

And I think that feeding, making sure that we've got the fiber right in the horses' diet, can help reduce the risk of some of these problems.

So let's talk about that a little bit.

I'm gonna kind of, my logic is moving from the horses' mouth all the way to their hindgut, okay?

And so the little bit of research, some of the research that's been done in the horse illustrates, so we've got, again, hay and pellets here, and you can imagine these hay and pellets might have a very similar chemical fiber profile, but they're gonna have a very different physical fiber profile.

And these are horses that actually had 3D motion sensors put on their heads to look at how they were chewing, and the way they chewed, not only the amount that they chew, but the way they chew, the way their jaw moves when they're chewing hay versus pellets is different.

That's gonna have implications potentially, to the way that their molars wear, so I want you to think about you know, floating a horses' teeth and the implications there.

Also, we know that when a horse chews, it's producing saliva, that's what's shown up over here, jaw movements and salivary outflow.

When they stop chewing, they stop producing saliva.

So I highlighted to you earlier on, that that saliva is really important.

We know that if you feed a horse a kilogram of hay or a pound of hay and a kilogram or a pound of pellets, they'll chew the pellets half as much and produce half as much saliva.

That's actually kind of shown here, here I've got a graph of, this is from some work by some other researchers where they looked at the amount horses chew hay, so the number of chews, okay, versus a whole host of other ingredients that were incorporated in those horses' diets, and by far they certainly chewed that hay, and this is per kilogram of dry matter, a lot more.

The other thing that we see, and this gets to horses being hay burners, this is the size of particles in a horses' feces, it's very large, ponies and horses, look at the size, again, these are micrometers, okay, but compared to a lot of these other animals that eat plants, horses are hay burners, they're very inefficient.

So, you know, all of you have probably seen oats in your horses' feces.

Again, I gross forage kids out all the time, because I'll go to a farm and I can, you know, I'll pick up horse feces with my bare hand, they're really not that gross, because it's not very digested, it's just kind of partially digested hay if you really look at it, and I think that you can learn a lot by, not only looking at what we feed our horse, but also looking at that fecal material.

So if we move into the horses' stomach, ulcers is an issue that probably many people are familiar with, and the picture on the left-hand side here is a cow's rumen, and this has been researched for years and years how important it is that when they feed that cow, they feed a whole range of different fiber lengths so that if you look inside that cow's rumen, we've got the long fiber kind of floating up on top and you've got the smaller fiber down in the lower regions here, and this is really important for the cow's health and the milk production.

But we haven't really thought about that with horses, Al Merrit did, and he put this picture into a really good review article that he wrote, but there's not been a lot of work really looking at this distribution of fiber within the horses' much smaller stomach, or within other regions of their gastrointestinal tract.

We can talk about the cecum and the colon and different regions, so that's really important.

The other thing is here, there's a great quote here, this is from Al Merrit, "I suggest that they" he's talking about microbes, "Colonize within the coarser fibrous ingesta" coarser is a physical aspect of fiber, right?

"Which collects towards the top of the stratified mat "of the gastric contents, where the pH of the contents "is more to their liking because the mat has not been fully penetrated by gastric acid." This really gets it, well if we're not, if I've got my horse on a mostly pelleted diet, and I don't really have that coarser fibrous material present in the horses' stomach throughout the day, then maybe I'm impacting the microbial populations that are present there.

That can be or could be very important, so I want you all to think about that.

This is from a slide of one of the ruminant students that I worked with and from Dr. John Heinrichs, this is for dairy nutritionists, they're talking about adequate particle size and how that lowers ruminal pH or why you want more of it so that you don't have this lower ruminal pH.

They put out jars like this where they show like look, if cows are eating a diet where there's enough of that physically effective fiber, and this picture here on the left-hand side should look immediately familiar to you because it's very similar to the one I put up earlier talking about the forages and the fiber that we might feed to the horse.

This is gonna separate out in the cow's rumen and that's where we're also interested with the horse.

I see a lot of parallels between what's been learned in ruminant nutrition and what we could learn in equine nutrition about fiber.

This is from one of my favorite papers, this was probably published by Marco Lopes in 2004, and this was some research that was done at Virginia Tech, and it was done in their veterinary school, they had cecally cannulated horses, so the picture you're seeing here on the right-hand side is of a horse with a cannula, a surgically implanted hole in their body's body wall, where the researchers could get access to their cecum.

There these horses do perfectly fine, they go along, but you can pull out a little plug and you can see what do contents of those cecum look like.

And so that's what you're seeing placed out on a table here, and what, these researchers were colic surgeons, and they were interested in looking, well how do different diets impact the risk of colic?

And what they found is that horses that were on a primarily hay-based diet, had this really nice separation of the, of the solid and the fluid components of the cecum, so there was a really good separation there, whereas as they increased the amount of grain in the diet, as they increased the smaller particle size, less hay in that diet, there wasn't this good separation, the water didn't really separate, I think of this as kind of cream of wheat, right?

It all kind of gelled together.

The colic surgeons were worried about this because it didn't move through the cecum and the colon as this would, you can imagine how those would go through a pipe, and that this hay/grain mixture also tended to trap more gas, so their thought was that this may, this more homogeneous mixture over here where there is a high grain diet, may actually trap gas and increase the risk of colic, okay.

So I think now is a good time to go ahead and throw up question five there.

I wanna know, do you understand, do you feel you understand what this term, what I'm talking about as far as physically effective fiber here?

Excellent, that's great, I hope you all will carry some of that understanding forward as you're thinking about the diet you're feeding your horse, and as you're looking at, you know again, if you go to a horse expo or something like that, when you're walking around and you're thinking about "Well what is physically effective fiber?

"What kind of physically effective fiber, "not just the chemical analysis, "that I'm gonna find on the bag of feed?" For the one person that doesn't have a better understanding, I'd be happy to talk to you, so you know, maybe we can straighten some of that up and Dr. Smarsh can provide my contact information, but let's keep going.

All right, so our horses are athletes, while fiber is a very good, important source of energy for the horse that is just out in the backyard, for a horse to compete, we usually have to increase the amount of grain, and we just, while that's important to do that, we have to be aware of the risks that are involved there.

So with increasing the amount of grain in a horses' diet, we decrease saliva production, we've talked about that.

We also are gonna change the characteristics inside the gastrointestinal tract, so we wanna be aware, okay?

If we're gonna decrease the fiber, you know this is what's gonna happen, we're gonna increase our risk of ulcers.

If we're gonna decrease the fiber, we actually are gonna change the feed that's available to the microbes and SCFA represents short-chain fatty acids here, that's actually some of the byproducts of microbial fermentation that happen.

Those are the important energy source to the horse, so we're gonna change some of those characteristics.

And finally we're probably also gonna change some of the water flux within the gastrointestinal tract.

So we've done a lot of this through domestication of the horse.

We've moved from that mainly grazing-based diet that wild horses do, to providing two large grain meals a day, to providing less of that physical fiber in their diets, and that's okay, but I would argue that we need to think back to, okay, how can we incorporate more fiber back into the diet, so that we can still get the athletic production, but we end up with healthier gastrointestinal tracts.

And ways that we can do that are, something that you'll see in the higher fat diets, that's one way of doing that, incorporating fiber sources like beet pulp that is fermented a little bit more rapidly and provides more energy to the horse than some of the less digestible fibers like the mature hays and that sort of thing.

This is because, and you know, a lot of the problems that we see are similar, believe it or not, in humans and horses.

So, you know, we've got here a picture of humans and horses running together, there are actually races in the world where humans race against horses.

My son runs track, and he is always telling me about all the gastrointestinal problems he's having, as much as I don't always wanna know that, but a lot of those are similar.

So I've got a question here that I wanna kind of get a feel from you guys as to what are some of the problems that you think are important.

So which of these things do you think are important?

And you can only chose one here, so you've gotta pick your favorite.

Many of you are probably like, "Just select all of these." I don't know, wow, look at this, so we don't have a clear winner, but at the top of our list we've got colic edging out gastric ulcers as major problems.

And then we've got enteritis, colitis and laminitis sort of in the back there, colitis, so enteritis and colitis are oftentimes not as clinically apparent, so it doesn't surprise me that many of you would be like, "Well I don't really know what those are, "I'm not sure if that's a problem for my horse." I think that subclinical inflammation of the small intestine or of the hindgut may be a bigger problem than we realize, and maybe where we see the horse depressed somewhat, we see slightly lower performance.

So there's just some things to think about.

This is helpful for me as I'm thinking about you know, what are the concerns that you all have.

And laminitis is kind of indirectly related to all of this, although it is related.

So I think that all of these are problems that we can reduce the risk of by incorporating fiber into the diet.

All right, Dr. Smarsh, we'll go ahead and keep going here.

So one of the problems, gastric ulcers, so some of you picked that, has to do with the anatomy of the horses' gastrointestinal tract, and this is a relatively dark picture here, but we're looking at the left-hand side of a horse, and what you see here is the ribcage, in front of the ribcage, this is where the heart and the lungs are, and behind it is the gastrointestinal tract.

One of the reasons that horses are at risk of ulcers when they exercise a lot, is that this gastrointestinal tract is smashing up against the stomach which sits right here behind the diaphragm, so the stomach is between a rock and a hard place, it's between the diaphragm and about 200 pounds of gastrointestinal material, and every time you gallop, it's getting squooshed, and when it gets squooshed, all of the acid splashes up on the upper regions and increases the risk of ulcers.

One of the things that we're thinking is that by incorporating more physically effective fiber into the diet, making those mats that we showed earlier, that we would actually help to protect the upper regions, the stomach, with more of those mats of fiber.

If we continue on and think about the anatomy of the hindgut of the horse, the anatomy of the hindgut of the horse is very well adapted to digesting fiber, that's why it's got all of these, see these kind of rings that are here, these are called sacculations, these are all homes for bacteria that are very good at digesting the fiber that's there.

If we don't have those homes filled with happy bacteria that have lots of good fiber available to them, things don't go very well, okay, and that's where we can have an increased risk of some digestive problems, not only inflammation of this region, but again, some of you talked about colic as being important, so colic in this region is really important, that's, the cecally cannulated horses, actually had a cannula right here in the cecum where they could reach in and get the contents of that.

So you know, you should look up and begin to understand some of this, this, in my mind as a nutritionist, the hindgut of the horse is perfectly formed for a high-fiber diet.

There are regions of this that are sort of set up very well, to separate fiber of different sizes and do all that and that doesn't work very well if we don't have long fiber and short fiber and different fiber types here in this region of the stomach, or rather, I'm sorry, the gastrointestinal tract.

All right, so this is our last question for you guys, you may have seen this before.

All right, so I think we've seen a little bit of a shift here, and I'm happy to see that.

As an equine nutritionist, having studied equine nutrition for many, many years and trying to work to improve the health and welfare of horses, I do think that dietary fiber is absolutely critical and there's a lot more we have to learn about it.

I hope that those of you that have participated in this do feel a little bit more strongly about that, your answers here indicate that.

It may have been obvious, I suppose, that that's what I was looking for her a little bit, but that fiber is really important, both as an energy source, but also for a lot of other reasons that are going to impact your horse, okay?

And I kind of highlighted those about halfway through this presentation.

Right, let's go ahead to my last slide here.

So in kind of wrapping things up, the reason I put this picture here is because, while there's some of these things your horse would not be eating, there's some nice grass over here on the side, okay?

So there's some good fiber, so you should be looking at what is going into your horse and again, don't be afraid, maybe you do wanna grab a glove, but to go ahead and explore what's coming out as well.

And I think that if horse owners work to educate themselves and understand the fiber in their horses' diet a little bit more, understand both the chemical and the physical characteristics of the fiber.

How do you describe that fiber, how can you talk about it?

That's, you know, when you're talking to a nutritionist, when you're talking to somebody that's trying to sell you some feed, if you could talk about that fiber a little bit more, it makes for a more informed discussion.

I think that all of us can improve the health and performance of our horses.

So whether we're talking about the problems that we see like ulcers and colic, or we're talking about trying to improve the performance because there's something subclinical going on where the horse is a little bit depressed, I think before you go out and are buying probiotics or buying the next best supplement, think about the fiber that you're providing into your horse, think about the hay, the forage, the pellets, whatever it is, all of those are okay sources, it's a matter of thinking about it, "Well how am I providing the fiber to my horse, "and what might I do to actually improve that "so that the health of my horse "and its performance improves?" I think there's a lot we can do there as horse owners before we go buy some fancy supplement.

So that's the end of my presentation and I think I have a little bit of time to potentially answer some questions, however that might go Dr. Smarsh.

- [Danielle] All right, thank you very much Dr. Staniar, as he said, we've got some time here if you've got questions, again, if you scroll your mouse at the bottom of the screen there should be a Q and A option or you could certainly put them into the chat box, so mull that over and type in some questions.

So I'm also gonna add in here some contact information for Dr. Staniar as well, so if you want to.

All right, so we've got, let's see two questions so far, the first one was email address for Dr. Staniar, that link I just put in after the webinar evaluation, into the chat box so you can find his email there.

So that's been answered.

The second question we have for you, "Is first-cutting grass mixed hay better for horses "or second-cutting grass mixed hay?" - So that is a, that's like one of the classic questions, that's a great one.

My answer to that question is going to be a sort of change gears on you, I have found that there are some very good first-cuttings and some very good second-cuttings and very good third-cuttings or fourth even.

There are also some very poor of all of those.

The main thing that you want to be paying attention to is looking at the maturity of the grass, okay?

So when was it cut?

So you can look at, you know, if I'm giving a forage presentation, I'll typically, excuse me, talk more about the leaf to stem ratio.

How much leaf is there?

If there is more leaf material there and less stem, there's going to be more nutrients and less fiber.

There's still gonna be a good amount of fiber, but that the greater amount of leaf, the less mature that plant was when it was harvested, that's gonna be better for our horses that require a little bit more energy, a little bit more nutrients, maybe the young, growing stock.

Whereas, if there's less leaf and more stem, that's a more mature plant that was cut because it had to be let grow out in the field, maybe it would be getting some rain and the farmer wasn't able to cut that and harvest it, that might be good for a horse like mine.

Mine's an older Quarter Horse gelding that I don't ride very much, he doesn't need a lot of energy, and so a higher-fiber diet can be beneficial for him.

You wanna make sure that they've had time to adapt to a diet like that.

But really the cutting of hay is less important than looking at the quality and the maturity of that hay, and matching that with the requirements of the horse.

Typically you can get a little bit, you know, people talk about that second-cutting being a little bit cleaner, having a little bit less weed material in it, just because of when the plants are sort of coming up in the field, so that is, that's another component but, you really, you're evaluating, when you open up that bale of hay, or are looking at first versus second-cutting, you're looking, "Does this bale of hay "have in it what I want?" - [Danielle] So I think this is a follow-up to that same question, I'm not sure 'cause it's from Anonymous, but is says, "My horses are older and don't have all their teeth, "they quid their heads if eating, they only get pellets." - That's a great, and another great one.

So how do we meet the fiber requirements of our older horses?

We've gotten really good at taking care of horses and feeding them, and now their teeth are wearing out and we have to provide them their fiber.

So in that case, yeah, you, there's a couple of different things that you can do, you can think about other fiber sources, so again, the senior feeds, that's why senior feeds were developed, those senior feeds typically have a higher fiber content and they will incorporate into those senior feeds, things like beet pulp, soya hulls, other fiber sources to satisfy the fiber needs of those older horses without forcing them to chew so much.

The other thing you can do is to soak those feeds so the horse doesn't have to chew as much, we're helping them to break it down some already.

You can even chew those feeds a little bit, and by that I mean, again, instead of feeding hay, try to find some of these chopped forage products where it's chewed up a little already, at least we've broken down the particles size a little bit for them, we're doing a little bit of the job of the teeth, but at the same time, we're providing some of that physical fiber so instead of just a, I would not wanna go to 100% pelleting diet, I would wanna find, you know, again, maybe some of these alfalfa pellets, or Timothy pellets, or cubes, and then I'd be soaking those so that that horse didn't have to chew them, and providing those, making sure that I wasn't letting the water leach away because I don't wanna lose any of the water soluble nutrients there either.

- [Danielle] Okay, so we have probably another six or seven questions, so we'll see what we can get through in the next couple of minutes, and if we don't get to all of them, again, we can certainly, you can email myself or Dr. Staniar and we can get back to you on that.

But we'll, for the next few minutes, keep working through them.

So we've got another question that says, "When you say grain, "do you mean oats, barley, corn, et cetera, "or any horse feed?

"I feed a low-carb, high-fat feed, "is it grain or feed?" - So it depends on who you're gonna talk to.

So I am, here I am in my ivory tower, the nerdy nutritionist at a university.

And in my mind a grain is a grain, so when I say a grain, I'm usually really talking about oats, corn, barley, wheat, those are grains.

When I talk about a concentrate or a pellet, I'm usually talking about that.

Grains can be incorporated into a concentrate feed.

Grains are really nature's concentrate, okay.

So, again, these are all, it's all semantics, it's all terms, right?

So it sounds to me like what you're feeding is not a grain, it's a concentrate, it's high-fat, I think that was what's said, it may have a certain fiber component to it, and I would think of that as more of a concentrate, that's kind of the terminology.

Dr. Smarsh, did I answer that question completely?

- [Danielle] Yes, I believe so.

So, all right, another question we have here, "Assuming that fiber needs change, the horse ages "and activity levels change, "when is a good time to start evaluating that?" - Always.

So as horses age, you should always be thinking about what their requirements are.

I've done a lot of work with young stock, with brood mares and young, growing foals, and I'm fascinated with how their diet is constantly changing, so of course I'm thinking about the brood mare's needs from an energy and diet perspective for lactation, with those young, growing foals, it's amazing, again, you know, we think about fiber, those foals are mostly drinking milk early on, but those of you that have dealt with foals, will also be aware that they will go and dig into their mother's pile of poop and eat a big bite of that.

And that's really, we believe, to help populate their gut with the microbes that are gonna help them break down fiber, and as much as foals will mostly drink milk, they'll start eating fiber very early on, small amounts of it, but they'll be eating it very early on, and that's probably to help feed and develop some of those microbial populations.

But they're gonna eat as young horses, you know, again, they're gonna be, their diet's gonna be changing continuously for the first two or three years of life, and then as they go into performance, usually around two or three years of life, and it depends on the discipline that you're doing, their diet's always gonna be changing.

And so you really wanna look at, what is the horse doing this year, what sort of performance are they doing and evaluating that and thinking about what is the dietary fiber that's gonna best suit that.

So if I've got a higher performance horse, let's say I've got a horse that I'm going to be doing three-day eventing with, and I'm thinking, again, now all I'm talking about today is fibers, there's a lot of other pieces to this, but if I'm thinking about the fiber for that horse, I'm gonna tend to, while the fiber like hay, and fresh forage are gonna be parts of that diet, I might incorporate more of the, more rapidly digested fibers, things like beet pulp that are a good energy source into that horses' diet, because I want that fiber providing a little bit more energy to that animal, and a little bit less bulk in their gastrointestinal tract, to allow them to, for athletic performance.

So that's a quasi-answer to that question, it's a kind of a tough question, but I hope it helps a little bit.

Go ahead.

- [Danielle] So we are at one o'clock, we do have a few more questions.

Dr. Staniar, do you wanna do one or two more? - I can take two more questions, and then I have to run to another meeting.

- [Danielle] All right, so we've got one that asks, (chuckles) "What type of hay is best, "orchard grass, Timothy, alfalfa, et cetera?" Go ahead-- - Okay.

- [Danielle] Give us your answer. (laughs)

- Yeah, my answer is, it depends, that one Dr. Smarsh knows.

So all of those can be excellent and all of them can be poor.

And so there is no best kind, it's, again, it's, and, again, I think we've had, Dr. Smarsh has presentations before, I know Laura Kenny does some presentations.

Thinking about, you know, again, as a horse owner you should really learn to evaluate your forages.

What is a good one?

You know, how do you evaluate that?

So all of those can be good and they all have their place, it's good that you're asking that question, because that shows that you're thinking about the right things, and all of those forages have their place.

For example, for my horse, again, old gelding that really doesn't do much, goes for a ride on Sunday, he doesn't need very much, I don't need a lot of alfalfa, I wouldn't incorporate alfalfa into his diet, I don't know that alfalfa's an important fiber source for him, okay?

So it's gonna depend on the horse, okay?

- All right, and then-- - One more.

- [Danielle] Yes, one more, so this one's, "I work at an animal sanctuary "and all the horses get two grain meals "along with hay, yet none of them are ridden or exercised.

"Do you think this is harmful, "should I recommend we decrease cut-green meals "and increase hay?" - No.

For a rescue, you've got a range of different animals that are usually there, you've really got a lot of variability in the horses that are usually present on some of those facilities, so they're not all the same as one another.

And so I think it's more important to evaluate each of those individual animals.

Certainly I know that, well I would say any rescue that's not Body Condition Scoring their horses, is making a mistake, so you should, you know, "What is the Body Condition Score of my horse?" and, again, Dr. Smarsh can tell you more about that or provide a whole nother presentation, but usually a one to nine score, and then I'd be basing my nutritional decisions, based on, what is the condition of that animal?

How well does that animal seem like it's doing?

And if I'm providing a grain, the reason that I'm providing a grain or a concentrate, to speak to my early questioner about that, either a grain or a concentrate for that animal, is because I don't think that the forage that I'm providing is meeting all of the nutrient requirements of those animals.

So oftentimes horse that come to a rescue, they're a little bit older, maybe they can't chew as well, or they're in poor condition, or they weren't maintained well before, so you know lots of times those are good places for some sort of concentrate or ration balancer, to make sure that we're really getting that animal a rich source of all of the nutrients that it really needs.

- [Danielle] Okay, thank you.

So we apologize for the few final questions we did not get to, again, I put my email address and Dr. Staniar's in the chat box, we are very happy to answer emails, so if you shoot us an email with a question that we didn't get to it, or if you've thought of another question, please go ahead and do that.

We've posted the link to the evaluation, again, if you could take all of one or two minutes to fill that out.

And finally, our next webinar will be on March 18th, with actually my colleague, Laura Kenny, talking about rotational grazing.

So you should join us for that webinar as well.

Thank you again, everyone, for joining us today, and thank you, Dr. Staniar, for your talk-- - Absolutely.

- [Danielle] And I hope everyone enjoys the rest of their day.

- Thank you, guys, it was wonderful, I really enjoyed it, so it was great, see you all later.