Skip to content

Other Resources

Ep. 053: Critical Nutrients for Healthy Foal Growth and What Can Happen If They Don’t Get Them

Co-host Katy Starr and guest expert Dr. Stephen Duren, PhD, MS, PAS discuss the critical nutrients foals need for proper growth, including: • The negative impact of certain nutrient deficiencies or excess of those nutrients • The most common nutritional growth disorders and how to avoid them • What foals can and should consume within their first year of life, in order to meet their growth requirements Have any topics you want to hear more about? Let us know at

Episode Notes

On this episode, co-host Katy Starr and guest expert Dr. Stephen Duren, PhD, MS, PAS discuss the critical nutrients foals need for proper growth, including:


• The negative impact of certain nutrient deficiencies or excess of those nutrients

• The most common nutritional growth disorders and how to avoid them

• What foals can and should consume within their first year of life, in order to meet their growth requirements


Have any topics you want to hear more about? Let us know at


***This survey is now closed - complete our short survey by Tuesday, February 28th to be entered for a chance to win Standlee free product coupons and some fun Standlee swag – ***


Leave a rating and review on Apple –


Leave a rating on Spotify –


From newborn to one year of age, young horses are known as foals. This first year of life is instrumental in determining how a horse’s future will play out, and poor nutrition can be devastating in a number of different ways. 

During this episode, Dr. Stephen Duren, PhD. equine nutrition specialist, joins us for a discussion about some of the most important nutritional elements of a horse’s diet. From protein to zinc, to the “big two” nutrients (i.e. calcium and phosphorus), 

Dr. Duren explains the importance of each and the issues that can arise if a foal receives more or less than the optimal amount. You will also learn about the digestive system of foals, when foals should be started on solids, and how the diet of a pregnant mare impacts the fetus. 


Key Points from This Episode:

  • The definition of a foal
  • Where you can access a comprehensive list of nutrients for horses
  • Nutrients that are critical for foal growth
  • Symptoms of nutrient deficiency in foals
  • The dangers of overfeeding a foal
  • How to support a foal whose mother is not producing enough milk
  • The age at which foals should start consuming hay and concentrates
  • Problems that arise due to a lack of protein
  • Why calcium and phosphorus are known as the “big two”
  • The importance of getting the calcium-phosphorus ratio right
  • How zinc impacts foal growth
  • The effects of inadequate levels of copper in a foal’s diet
  • What a foal’s digestive system looks like
  • How the diet of a pregnant mare will affect the foal after birth
  • The growth stages that a foal goes through during the first year of life
  • How your goals for the foal should determine their nutrition management plan
  • The benefits of a smooth growth curve
  • How to minimize weight issues when a foal is weaned off his mother’s milk
  • Advice on what to feed a growing foal
  • Some of the most common developmental orthopedic diseases
  • Exercises that young, growing horses should not engage in



Notable References:

  • 2:59 - Nutritional Requirements of Horses (Sixth Revised Edition 2007) -
  • 14:54 – In reference to a study done in New Zealand regarding the effect of copper supplementation on the copper status of pasture-fed foals -
  • 35:05 – In reference to horses who had stifle and sesamoid issues, they followed them and based off their radiographs, if they appeared in a 2 year old sale to see, did they race and how did they do? - Pages 424-427 chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/
  • 38:45 – Studies with sheep and horses to determine if circling or loading a joint unevenly could cause joint damage - &





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

Katy Starr (00:01):

Hi, I'm Katy.


Dr. Tania 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):

We are celebrating two years of bringing you helpful nutritional content and inspiring experiences from equine, livestock and small companion owners and influencers who are making waves wherever they go. To thank you for being here with us and sharing our space with your friends, we'll be giving away free product coupons and some fun Standlee swag. All you need to do to be entered to win is rate and review our podcast and complete the short survey that is linked in our show notes. That's it. Thank you for celebrating two years with Beyond the Barn. We couldn't do this without you. 


Welcome back to another episode of Beyond the Barn, and I have Dr. Duren joining us today to talk about foal nutrition management. Thanks for being here today, Dr. Duren.


Dr. Stephen Duren (01:18):

Thanks for having me, Katy. It’s always great to contribute to a great podcast.


Katy Starr (01:22):

Before we get started on today's topic, I just want to remind our listeners 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. Be sure to always work with your veterinarian and nutritionist before making any drastic changes to your horse's feed program. Or you can reach out to us and talk directly with Dr. Cubitt or Dr. Duren on any specifics that you would like to know. So Dr. Duren, just to get us started, how would you define a foal and where did this term come from?


Dr. Stephen Duren (01:58):

So foal is a term that's used widely for a young horse. Typically it's a horse that's less than one year of age. Now other terms will be utilized as well. So some people will often say, well the foal is the newborn horse from the time of birthwhile he's nursing on his mother or the dam. And then once that happens, although it is still technically a foal, they often refer to them as weanlings at that point. And then certainly once they get to be 12 months of age then they become yearlings. So foal is technically from birth to a year old.


Katy Starr (02:40):

Excellent. And what nutrients are critical for growth in foals?


Dr. Stephen Duren (02:46):

There's a laundry list, if you will, of important nutrients that are critical to the growth and development of a foal and the nutrient requirements, the requirements for those specific nutrients are all outlined by the National Research Council, "The Nutrient Requirements of Horses.” So those are not only listed but the amount depending on the growth rate of the individual foal are all outlined as well. So you'll see that there's quite a large number. So I usually try to get the major ones first. The ones that are most likely to be deficient in a diet, those that are most likely to cause us issues if we don't have them properly fortified in the diet. So the first is the calorie or the energy content of the diet that will provide calories, that will help tissues, first of all, be maintained and then provide energy for that foal to actually grow. Protein obviously is a big one. Muscle and bone are primarily protein and then more specific proteins are made up of individual amino acids. The first limiting for a growing foal would be the amino acid lysine. Minerals, again, lots of minerals to concentrate. I typically concentrate on what I call the big four. The big four are those that are most likely to be deficient or most likely to not be in correct balance in a foal’s diet. And those are the macro minerals, calcium and phosphorus and the micro or trace minerals, copper and zinc.


Katy Starr (04:23):

And so with calorie intake for example, I just want to go through some of these, but if a foal is not getting enough calories, what are we going to see in the growth of that foal?


Dr. Stephen Duren (04:37):

Yeah, so if he's not getting enough energy, typically those foals will have a look where you can clearly see their rib. They won't have a developed top line or croup area that over the rump of the horse. They'll have a potbellied appearance, often long hair. They're just simply not getting the calories to grow adequately. What you see from a measurement standpoint is these foals are smaller than their counterparts, horses of a similar breed andage. These foals that aren't getting enough calories in the diet are smaller.


Katy Starr(05:11):

And then obviously if they're getting too much energy then they're just going to be putting on too much weight and that could be also not be a good thing for a growing foal.


Dr. Stephen Duren(05:22):

Actually Katy, it may be worse. We know that immature bone, that of a foal, a growing foal that's actually carrying too much weight will damage the skeleton and actually precipitate a number of the growth anomalies that we see in these young growing horses. So controlling the calorie content of the diet is critical. The nice thing about that is calorie content or energy content of the diet is the only dietary factor you can look at the foal and determining are you doing correct thing. Is the foal getting fat? Is the foal getting thin? Having said that, it's really hard to control milk production of a mare and during lactation, when that foal is actively nursing, a major part, especially for the first 60 days of lactation, a major portion of the energy content of that foal’s diet is coming from mare's milk.


Katy Starr (06:18):

And for example, if the mare is not producing enough milk during that timeframe to support the foal, then you'd probably need to give some sort of supplemental milk to the foal.


Dr. Stephen Duren (06:29):

Likely not milk. Milk is certainly one thing you can use. But rather than that, I typically will go and begin to introduce concentrates, energy containing grains with proper vitamin mineral fortification for a growing foal, because he's eventually going to eat those anyway. So rather than trying to get him to drink milk powder that's been reconstituted or a milk pellet, I'll go the other way and start to introduce a grain concentrate, designed for a growing foal.


Katy Starr (07:01):

And how early can you start that?


Dr. Stephen Duren (07:03):

You can start it from a curiosity standpoint. Often times within a week, seven days beyond birth, they become curious. But generally I want my foals to begin to eat solid feed, fortified with vitamins and minerals by 60 days of age. And the reason this is important, Katy is because while that fetus is in utero that mare is storing primarily micronutrients - copper, zinc - those trace elements in that fetal liver. That foal will then go ahead and utilize those for about the first 60 days of life. Ok. And those provide nutrients to that foal after about 60 days of age, those become exhausted. And then external sources such as what's coming from the feed, from pasture, from hay, things will foal is eating, begin to make that up. Ironically, mare's milk is not a good source of copper and zinc. It relies on that foal to be properly fortified in utero from the mare's diet, not from drinking milk early in life.


Katy Starr (08:13):

Interesting. Okay. And then you were talking about protein. So with protein, what can we see with a growing foal if they're not getting enough protein? And then the other side of the coin, what if they end up getting too much?


Dr. Stephen Duren (08:27):

Yeah, so a foal that is deficient in protein, he's actually deficient in amino acids. And for the body to form protein, proteins that make-up muscle and bone, they have to have a full complement of amino acids to make that individual protein. If protein and more importantly certain amino acids are missing or limiting, then you won't get muscle deposited, you won't get bone deposited. So these foals again will lack muscle mass, will also lack bone development. Now also because hair is modified protein, these are those horses that won't shed that foal hair out and develop new hair, they'll be shaggy, that sort of appearance.


Katy Starr (09:14):

And then let's talk about some of the minerals that you were discussing earlier. So how about with calcium? What can we see? I mean obviously that's a huge part of bone growth, but what can we see with deficiency, but then also maybe if there's too much calcium that's given and consumed by the foal?


Dr. Stephen Duren (09:34):

Yeah, so calcium is one of the big two. Calcium along with phosphorous are the major minerals associated with bones. So most of the research on calcium requirements and phosphorous requirements for growing horses were done in the seventies. Ok. We realize that very early, not me, I'm not that old. Popular belief says that I'm older, but I'm not that old . Anyway, those studies were done very early because we knew how important those particular minerals are. So a calcium deficiency, you'll get such things as rickets, bone development issues. Calcium is required for muscle contractions so you'll have a host of issues that are associated with a calcium deficiency.


Katy Starr (10:18):

And then you said phosphorus also. How about with phosphorus? What can we see happening with the foal if there's a deficiency with phosphorus or too much?


Dr. Stephen Duren (10:28):

Yeah, so with calcium and phosphorus, there's two things to consider. First and foremost, are we meeting the requirement for that growing foal for both calcium and phosphorous? Are we getting enough grams of calcium, enough grams of phosphorous in the diet? Then once that's addressed, then we address the ratio of those two minerals. And in the total diet we always want more calcium than phosphorus. If you take a bone, and they did these studies really early, they took a bone grounded up simply to determine how much calcium versus how much phosphorus is there. The bone has about two parts calcium to one part phosphorus. And so that was a target ratio that we wanted to have in our diets. So first and foremost, we need enough calcium and we need enough phosphorus and then we want the ratio to always contain more calcium than phosphorus. So horses that don't have enough phosphorus, again critical for bone development, these horses will also get a lot of the developmental orthopedic disease, joint issues, bone issues, osteochondrosis, some of those sorts of things.


Katy Starr (11:38):

And so if there is more phosphorus than calcium, what are you going to see happen?


Dr. Stephen Duren (11:45):

Yeah, that in short is what you'd call a train wreck because that phosphorus will actually interfere with the ability of calcium to get absorbed. Then you'll have poor calcium absorption and a number of bone problems. The other issue is calcium is one of those minerals that is controlled in the blood, is homeostatically regulated. So if the blood does not have enough calcium, remember it's important for muscle contraction and a lot of other things, if the blood is seeing and they're not absorbing enough calcium from the diet, the blood levels of calcium would tend to be low. To correct that it's going to pull calcium from the bone and put it into the blood, so that muscle contraction functions normally. You often see they had a situation called big head disease or miller's disease and these are horses that ate a diet that was higher in phosphorous than calcium. In respect to miller's disease, these horses were actually eating wheat as a byproduct of the bread industry, the flour industry. And because they were getting more phosphorous in the diet than calcium, they were absorbing calcium from the bone and then replacing that bone with fibrous connective tissue and it gave them the appearance of a big head or a swollen head.


Katy Starr (13:08):

Okay, so a couple other minerals that you mentioned earlier were one of them was zinc. So how does zinc impact a foal's growth in that, you know, if there's a deficiency there or if there's too much in the diet, what are we going to see happen?


Dr. Stephen Duren (13:24):

So zinc is a trace mineral and it's involved in a number of enzyme reactions to form different things in the body. The biggest one is protein. So to form a protein, zinc is often involved in the enzymatic reactions for that protein to be formed. So if you have a low zinc concentration, you are not going to have adequate protein synthesis. One of the first areas you see with low zinc concentration is poor skin and haircoat. Again, remember that hair is modified protein and that's where you often will see that happen. But zinc can also be in excess in the diet and because it is a positively charged cation, it can interfere with the absorption of other positively charged cations. So balance is also important. You need enough but you also can't have excessive levels or you won't get other trace elements absorbed.


Katy Starr (14:26):

Right, okay. And then with copper, what do we see with copper deficiencies or an excess of copper in the diet?


Dr. Stephen Duren (14:32):

Again, copper’s another trace element, again involved in many of those enzyme systems. So inadequate copper, they'll have slow growth rate, they won't have adequate cartilage development, some of the soft tissue development, they won't have. The increase in the occurrence of developmental orthopedic disease. A study that was done, interestingly one that was done first in the United States in the mid-eighties and then sort of repeated in New Zealand, actually looked at pastures and said, alright, these pastures are, especially in New Zealand, very rich with trace elements, but what if they aren't? What if those foals aren't getting enough copper and zinc? And they actually looked at the growth and said, boy, they've got adequate protein and adequate energy, these foals look totally normal. But when they looked at them from a development standpoint, because the diets they were eating were deficient in those trace elements, they weren't developing a sound skeleton. So those studies were initially done in central Kentucky, repeated in New Zealand where it's often thought we have such great pasture, we don't need to supplement these horses. And they actually showed that even minor deficiencies in that can cause issues.


Katy Starr (15:48):

So let's get into the digestive system of a foal, what does that look like when they're first born?


Dr. Stephen Duren (15:56):

Yeah, so the digestive system for a foal, they're actually born with what they call a sterile digestive system. And remember that horses are high gut fermenters, so they have to have a microbial or a microbiome, if you will, develop in their hind gut. So once they're born, the things that they touch with their mouth, the udder of the mare, the grazing, the nibbling on wood, anything that's ever touched a horse, begins to inoculate that digestive system. So they develop because of nursing and because of the normal mouthy kind of feeding behavior of a foal, their digestive system becomes inoculated quite quickly. So by time they're two and three weeks old, that foal has actually developed some ability to choose soft grass and actually digest it. Remember the enzyme systems that digest the carbohydrates, the sugars and starches, they're already there, but they'll begin again to be able to ferment some of those more soluble fibers.


Katy Starr (17:02):

So you talked about earlier how they first are obviously consuming their mother's milk and everything and by two to three weeks they're actually able to start digesting, you know, some grasses and things like that. As long as everything's going well, how long are they on just their mother's milk and how often are they eating?


Dr. Stephen Duren (17:19):

Yeah, so the foal, once it's born, they're certainly not like an orphan calf or an orphan lamb where you know they're fed two or three times a day. The normal feeding behavior of a foal, they'll nurse almost every hour. They take in small amounts of milk on a very frequent basis, so their nursing is very frequent. As that foal grows, the nursing cycle will be longer and less frequent. So as they begin to eat grass, as they begin to eat other things, they're not constantly nursing, if you will, or irritating that mare and wanting to nurse all the time. But foals are very much like that. They're different than a calf. They don't take in the volume, much smaller meals and more frequent.


Katy Starr (18:06):

And then what are kind of the growth stages of the fall in that first year? You had mentioned that you know, within that first two or three weeks they're able to start digesting things like grasses and things like that and that microbiome. How does the progression of the diet move forward throughout that year?


Dr. Stephen Duren (18:24):

Yeah, so typically once the foal’s born, the foal will certainly by two weeks or three weeks they'll certainly be interested in food. They'll be starting to consume whatever forage is available to the mare. Whether they pick at the leaf portion of the hay or the fine stem of a hay or whether they're starting to graze or to nibble on some grass. Then the next thing that they do is they'll become interested in the grain portion of the diet that the mare’s eating. Some mares are quite friendly, and they'll share that with a foal, others won't. But that foal is interested in that grain. So the growth rate of a foal from birth to a year old is very rapid. Some depending on breed, some of those horses can have 90% of their skeletal height by the time they're a year of age. So it's very rapid. So the thing that I want your listeners to get is it's very important how you feed that foal, once it's born, to a year.


Dr. Stephen Duren (19:30):

But it's also important to feed the fetus, to feed that foal before it's ever born to make sure that mare is properly fortified so that fetal liver is properly mineralized or has enough mineral in it to keep them going. So they'll certainly pick feed by time they're 30 days of age. I like to begin to introduce some supplemental feed to that foal, certainly by 30 days of age and by 60 days of age I want that foal eating a known amount of supplemental feed. Now that known amount of supplemental feet kind of depends on the endpoint or what you're trying to accomplish with that particular foal. If that particular foal's going to be shown in halter classes or campaigned in the show ring early in life, their growth rate has to be faster. They're looking for a more mature individual. So they'll often feed those horses a higher calorie content, a higher nutrient content.


Dr. Stephen Duren (20:31):

On the other hand, if your goal is simply to say I'm not going to do anything with this horse until it's a five-year old, then you can have slower growth. But regardless of the growth rate, you have the vitamin mineral fortification correct to support that rate of growth. In other words, you can't just say, I'm going to feed lots of calories but I'm not going to provide enough copper and zinc. So you'll get the very rapid weight gain, muscle development, but then you won't have adequate mineralization of the skeleton. So it goes hand in hand. They have to be properly fortified to support the rate of growth you desire.


Katy Starr (21:12):

So you mentioned that obviously that first year is a lot of growth is happening with that foal, but kind of like with human babies they tend to have growth spurts kind of throughout their first year. They have it laid out where certain weeks generally or month stages, they tend to hit growth spurts. Do foals do that throughout that first year or is it just pretty much consistent throughout that whole year?


Dr. Stephen Duren (21:38):

No, they do go through growth spurts, but we try to minimize those and we try to make sure we're having consistent growth of that foal and that's so we have what they call a smooth growth curve rather than a growth curve that has many spikes and valleys in it. We want that foal to have a smooth growth curve. So we want to be able to supply those nutrients, that energy, the protein, the trace elements so that they can support that skeleton and continue to grow. What is sometimes devastating is if a foal goes through, when he's separated from his mom at the time of weaning and actually goes through a weaning slump, where he actually loses weight, he wasn't properly prepared for weaning and then once he gets over the separation anxiety from the mother, then he has rapid weight gain. That rapid weight gain not supported by proper mineral fortification can be an issue with growth anomalies.


Katy Starr (22:40):

So how can you support that foal when they are being weaned to minimize that from happening?


Dr. Stephen Duren (22:48):

The key to that is plan ahead. That is the whole key in feeding horses is anticipate what's going to happen next. So prior to weaning, a full three in four weeks, you want to make sure that they've had their proper vaccinations, that they're on a proper parasite program so that all that doesn't happen on the day of weaning, you don't add more stress. You also want to make sure that that foal is accustomed to eating his own feed, not just sharing with the mother but knows how to eat out of a bucket, that you're confident that the foal is eating the proper amount and can eat and knows what to do in that situation. Then other things you can do to minimize stress is in a group of mares and foals, just remove one mare at a time. Okay. So that one foal will be whinnying, but then he'll look around at his buddies and the other mares and they're not whinnying and then he has a tendency to settle down much faster. So rather than abruptly taking all the foals away from the mares all at once and the chaos that ensues, a gradual weaning program where you're moving one or two mares from a group at a time, that seems to reduce the stress.


Katy Starr (24:03):

Right. So they're not all feeling the same feels


Dr. Stephen Duren (24:07):

Exactly. The other thing is we tend to often in large farms where we have multiple mares and foals, we'll typically wean foals two at a time. So they have a buddy and that is good as well. So sometimes you can even put those two foals in the same stall so they're not locked in that big stall by themselves. They actually have a buddy for a week or two.


Katy Starr (24:28):

And so you mentioned that there's obviously different kind of growth rates depending on what you're wanting to do with that foal, what your goals are for that full. But how do you determine how much hay and feed a foal should be consuming, like when you're getting them started with that diet, when you're building that diet, how does that start off and what does it look like?


Dr. Stephen Duren (24:53):

Yeah, so for a growing foal, I will never limit forage intake. I'll always try to make sure that he's in a good pasture, he has adequate pasture grass available. And if that's not available, if you're not in a pasture situation, I will always make sure that that foal has free choice forage in front of him all the time. That's very important. We can debate the type of forage, you know, whether it's an all-grass forage, whether it's a mix of grass and legume - grass and alfalfa or grass and clover for instance - or a straight legume such as alfalfa, but they need to have forage in front of them all the time. Okay. They will consume that. If you provide a free choice, you don't have to worry about, okay, I'm going to provide three pounds of grass forage and a pound of alfalfa.


Dr. Stephen Duren (25:46):

They will regulate that very nicely. The other thing is, remember that horses are designed to digest fiber. That's what they are is fiber fermenters. So we want to make that the number one component of the diet. Then as far as the amount of concentrate to feed, that's where it comes to a point of what is our end product? What are we trying to produce? So if that is a quarter horse weanling that we're going to try to show as a weanling, we need to make sure that it's adequately developed. Those horses will often be on the upper spectrum or the higher feeding rates that are on bagged feed products for young growing horses. On the flip side, the opposite of that is a foal that was on a mare that was a great milk producer that foals in very good condition. We want it just to be a sound three-year-old or five-year-old, maybe it's a warmblood, something like that.


Dr. Stephen Duren (26:45):

Oftentimes they're fed concentrated protein vitamin mineral source or what we call supplement pellets rather than a feed that has a concentrate that has lots of energy content. So again, it depends on the endpoint that you're trying to achieve. The key is you've got to follow label directions on the bag. Feeds designed specifically for growing horses, not senior feeds, not maintenance feeds, but growing horse feeds and at the appropriate levels. If that seems too much, then that's where you can get a nutritionist involved, your veterinarian, to help you make those decisions, to make sure that diet is fortified. Because despite our best efforts, they're still going to grow and if we don't provide them proper vitamin mineral fortification, they will not grow a sound skeleton.


Katy Starr (27:38):

Well, and those feeds, the directions, you know, the amounts that are on those bags, they're fortified in a way that the foal would be getting all of the nutrients that they would need. So if you feel like that's too much and you cut back on them, maybe that's less food, but what are they missing out on? What are they losing out on from the nutrient requirement side by doing that?


Dr. Stephen Duren (28:00):

Yeah, so that would be the equivalent of the human. If we use an infant for example, that says when you're mixing formula, for instance with an infant and you're supposed to put four scoops, whatever that scoop is in a certain amount of water, and you say, well my baby seems to be getting fat so I'm only going to put three in, all those trace elements that are designed into that formula then are not being properly supplied. Okay. So then that infant can have trouble. To use another human analogy that would be the same of you go to the doctor and you have a medical condition, he prescribed a medicine for that and you decide, well he wants me to take four tablets a day, but if I only take two, the prescription lasts longer. Again, you're not getting what was intended. So when you feed a feed, especially a feed for a growing horse and you're feeding off label, that foal is not getting the nutrients that that manufacturer intended and that the likelihood of unsoundness, developmental issues goes way up.


Katy Starr (29:07):

And you were talking about the hay aspect of it there. With grass types or legume types like alfalfa. As a nutritionist yourself, when you're working with clients, do you have a preferred recommendation for the hay type or is it dependent on the horse and its goals for where you want it to be going?


Dr. Stephen Duren (29:32):

Kind of both, if you will. So if it's a nursery or a farm that has adequate quality grass, I'll certainly let those foals grow and consume the grass hay. And then when that foal comes up during the day for a couple hours to rest with the mare, typically these come in and out of the barns for veterinary work to get pregnant again for the next season. When that foal is in the stall, I give that mare and foal access to legume hay because they're already getting grass outside. I just boost the protein and boost the energy content of the diet by feeding some alfalfa in the stall. If the mare and foal are in a situation where pasture's not available, they're in a dry lot situation, I like to have free choice grass forage out for that mare and foal. So they can go to a feeder or there's grass hay available all the time. And then I will limit feed, alfalfa to those mares in foal. And the reason I do that is first for the mare, because a lactating mare has the highest nutrient requirement of any animal on the farm. She requires the calories, the protein, and the calcium that's in alfalfa hay. But it's also good for the foal, so as long as I'm not overfeeding that, so a limited amount, say between 25 and 30% of the diet, forage component, I will absolutely utilize an alfalfa for that.


Katy Starr (31:00):

When can we expect to see different teeth coming in for the foal and how does that influence the diet of the foal, what they're consuming, things like that?


Dr. Stephen Duren (31:11):

Typically with any animal, the ability to properly digest a diet depends on the ability of that foal to adequately chew, whatever they're taking in, to reduce long stem hay to a particle size that they can swallow. To reduce grass to a particle size that they can swallow. So again, they develop that and they will have constant eruption of teeth as they grow. So it doesn't particularly impact our normal management of a foal as it goes from a nursing foal to a weanling to a yearling. The traditional feeds that are fed, whether that be a forage, a concentrate, a grain concentrator, a supplement pellet, they'll have adequate dentition to get that properly digested.


Katy Starr (31:58):

And you mentioned some of these when we were talking about the trace minerals and the other essential nutrients that a foal requires for proper growth. But can you tell us a little bit about what are some of the more common nutritional or growth disorders that can happen with foals if they're not given a proper diet? Which ones are some of the ones that you are most concerned about or that you see most frequently?


Dr. Stephen Duren (32:26):

Yeah. With growth anomalies in growing horses, there's a generalized term called developmental orthopedic disease, DOD, in foals. And it's a catchphrase, if you will, for a number of anomalies that foals can have in the growth cycle. So these things can be many different things. They can have what they call physitis. Physitis is where at the end of long bones, just above the joint or just below the joint, those particular folds will have a lumpy or hourglass structure or look to them. If you touch them or you palpate them, they'll actually be warm to the touch. You can have angular limb deformities. You see those quite often in foals. Flexor deformities, that's when the tendons will contract and look like he's walking on their tiptoes or a hoof will be or appear to be misshapen. You can have more serious lesions where the cartilage at the joint service did not get adequate circulation, adequate nutrient fortification and actually gets a hole in it, what they call an OCD lesion.


Dr. Stephen Duren (33:36):

So remember that's at an articular surface or where those two bones are moving across each other. And if you get a divot or a place where the cartilage is inadequate, you can see how that would cause pain and that could cause a lameness. So from a visual standpoint, physitis would probably be the most common one that you would see, that and angular limb deformities, those are what you can easily see. And then probably the third would be the flexor or the look that the foal is walking on histiptoes or doing something like that. The articular problems, the developmental orthopedic disease, most of the time those require radiograph or x-rays to actually see those, but those become apparent on free cell, x-rays, those sorts of things in horses. The other thing alt mentioned, and a lot of people forget this, there's been a number of studies where thoroughbred horses that are sold as yearlings that go through public auction, they have what they call a radiograph repository where all the yearlings that sell at that auction will have their x-rays available for anyone who wants to look at them.


Dr. Stephen Duren (34:51):

So typically, you know, the veterinarian, if you're interested in a horse, you'll get one of your veterinarians that you've hired to go look at the radiographs and make sure they're good. Well, this has actually precipitated a lot of study and a study that was just published at the American Association of Equine Practitioners. Their last meeting that was held in November in Texas actually looked at that. And so they looked at horses that had stifle issues and that had sesamoid issues, and then they followed those horses based on their radiographs and they followed those horses if they appeared in a two-year-old sale. And then they followed them, did they race and how did they race? And so they rated some of these more common things that may prevent someone from buying a yearling and how could they affect the final performance of the horse. And the reason I mention this is remember, bone is not static, bone is dynamic. It changes, it heals. Okay? So a lot of things that will happen to a young growing horse, some of those will actually heal with proper nutrition, will heal with time. So we certainly don't want to make a nutrition mistake with a young growing horse, but some of those, ok, the horse's skeleton has the ability to repair itself with proper nutrition.


Katy Starr (36:13):

I think that's really great to hear. That kind of encourages people and lets them know that it's not like a total loss. Cause if you see some of those issues that occur as a yearling.


Dr. Stephen Duren (36:23):

They do heal and just as if you had a child that broke their arm that is not, that they'll never be a successful gymnast or baseball player or whatever that happens. Those injuries, again, with proper nutrition and attention will actually heal. And that's the same with some of these developmental issues. They're developmental, that's when they occur. If they're unaddressed, they can absolutely decrease performance. But if they're properly addressed and properly taken care of from a nutrition and management standpoint, many of those horses can actually recover and go on to have successful performance careers. Whether that performance is racing or some other discipline.


Katy Starr (37:05):

Dr. Duren, what would you like to see in terms of exercise for a growing foal? Obviously this could differ depending on the, again, the goals of the foal, but what would you like to see?


Dr. Stephen Duren (37:17):

Yeah, remember that exercise is important for strengthening bone. So the cycling or exercise actually cycles the bone and puts stress on the bone. Then the bone responds to that stress by getting stronger. So if a foal is not getting adequate exercise, if a foal is confined to a stall, if you don't have adequate turnout for a growing horse, they'll actually lose bone density. Their bone will be designed for what it's doing. So a foal that's not getting exercised, their bone is not designed for horses exercising. So then if they get turned out and they overplay and they overrun, you can actually cause injury. So we absolutely want to see our foals out in paddocks, out running around playing. And then by the same token, laying down in the sunshine, sleeping and resting and that bone cycling and becoming stronger.


Katy Starr (38:17):

Are there any certain types of exercise that, things that we do training wise with maintenance or older horses, are there any of those things that would be not good to do for a full or even, you know, a younger horse, like a yearling or anything like that? Are there any types of exercise that we should be avoiding with them just because of the type of growth that they're having?


Dr. Stephen Duren (38:43):

Actually, yes. There was a study that was done several years ago and they actually utilized sheep as a model for horses. And I realize that that sheep aren't horses and horses aren't sheep, but they looked and matched up based on life expectancy and tried to match, okay, what happens if you exercise a sheep or a lamb at a certain type of exercise that would correspond to that bone density or that that same chronologic age in a horse. So they were exercising either in a straight line or in circles, and they found that circling or loading a joint unevenly, cause the horses always turning, in this case the sheep is always turning. There was much more joint damage in that sort of situation. So foals that are out in a paddock and running and playing okay, will certainly do some circles, but a lot of that running and playing is in straight line where the bones are being loaded evenly. So what I try to avoid with young growing horses is the desire to have forced exercise and do it in a tight circle, tight circles where that animal is always weighting his joints unevenly can be damaging. So I try to avoid that. If I do have to do exercise in a circle, I try to keep it slow and certainly go both directions rather than a singular direction.


Katy Starr (40:11):

Right, okay. No that's good to know. Do you have any other management tips that we should maybe be taking into consideration when it comes to caring for a growing foal?


Dr. Stephen Duren (40:22):

Yeah, as we mentioned earlier, you've got to start with the pregnant mare. If you don't adequately fortify the diet for a pregnant mare, you're much better off going to a yearling sale or a two-year-old sale. Take your favorite veterinarian with you and x-ray and buy whatever color horse you want. But if you're going to raise a foal, you've got to be serious about feeding the pregnant mare properly. And then you've got to start that diet for that foal. Begin introducing solid feeds three weeks to a month of age, certainly have him on his own diet by 60 days of age. And then all the label instructions. If the label instructions seem like it's too much feed for your horse, there are more concentrated, such as the protein, vitamin, mineral supplement pellet or balancer pellets that you can use. But you've got to provide those trace elements to have sound skeletal growth.


Dr. Stephen Duren (41:19):

So if you have all the bricks in place but don't have the mortar or the cement type glue, the wall will still fall down. So you need to make sure those trace elements are the glue, so to speak. You need to make sure those are in place. So if you're going to raise a foal, you need to think about it and you need to take it seriously because nutrition mistakes you make in that first year, if you make serious nutrition mistakes, they can't impact performance for a lifetime. Now we said some of them heal, but if you really mess things up badly, those horses will never reach their true genetic potential.


Katy Starr (41:56):

Great things to think about. And like you said, it's a very serious thing to be breeding mares and having foals and things like that. And so I think if we set ourselves up for success in it doesn't hurt to make sure that you're working really closely with your veterinarian and equine nutritionist just to make sure that you guys have all your ducks in a row and give that foal a good steppingstone to do what they need to do and what your goals are for them in the future. But Dr. Duren, thank you for this conversation today. I think this has been a really great topic for us to hit on. We haven't talked about foal nutrition very much before, and so hopefully our listeners appreciate hearing about this. And for our listeners, if you have any topic ideas that you would like us to talk about on the Beyond the Barn podcast, please reach out to us at We'd love to hear from you. And Dr. Duren, thank you for giving your time to us today and letting us know about all this great information.


Dr. Stephen Duren (43:04):

Well thank you for having me. And again, if they have questions, ask your nutritionist, ask your veterinarian, post it on our website. We'll be glad to try to help you, but it's really important to get these foals off to a good start.


Katy Starr (43:15):

Excellent. Thank you so much. 


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.


If you enjoy the Beyond the Barn Podcast, please consider taking a minute to rate and review the podcast on these popular platforms.