Why Some Horses Don’t Get Laminitis

First of all, I’d like to begin by saying ANY horse can develop laminitis under the right circumstances. Bingeing on grain is one unfortunate example. But for the purposes of this post, I’m going to focus on pasture-associated laminitis–the kind of laminitis which it seems is becoming more and more common these days.

If you’re like me, you may be wondering why some horses develop this horrific condition while others never do? Or maybe you’ve heard of someone healing their foundered horse on grass and thought, what the heck? After much studying, observation, and pondering on this condition, I’ve developed a theory about all of this. I’ll get to that shortly.

But first, I’d like to back up just a bit. . .

You see, every day over the last few years, when driving my kids to school, I would notice four vibrant horses on a huge, lush pasture. The kind of pasture that just screams, founder! These horses weren’t overweight and they all appeared shiny, healthy, and happy. Much more so than the ones at the farm just down the road, where each horse was kept in an individual small pasture for the day (I believe they are stalled at night). I knew there was a reason why the four shiny horses were healthy and happy–they were living a much more natural lifestyle, but I still kept wondering–why haven’t they foundered?

Over the years, I’ve also marveled at a small herd of miniature horses which are kept on lush pasture just down the road from me. How was it that they weren’t developing laminitis when so many minis and small ponies do?

I’ve had horses nearly all my life and while they’ve always lived on pasture for the most part, it wasn’t until the last few years that I begin to worry each time spring rolled around. What if this was the year it happened? The problem wasn’t that anything had changed–it was just that I was more aware of pasture-associated laminitis, and I was terrified it would happen to my horses. I began to take measures to protect my horses such as keeping them confined in a dry lot or small pens during daylight hours (with hay, of course), building a track system, using grazing muzzles, etc. But all the while, a tiny voice kept saying in my head–is this really necessary?

In time, and as learned more (and began to develop my theory), my worries began to fade (along with my need to micro-manage my horses’ lifestyle). I developed a K.I.S.S. management plan which has taken a lot of the stress out of horse care for me.

But my theory is this: There are four factors which play a major role in the development of pasture-associated laminitis. They include stress, mineral imbalance, toxins, and seasonal/ environmental fluctuations affecting the sugar levels in grass. In most cases of laminitis, I believe at least three of these factors need to be in place. Yes, I realize I’m not a vet or a researcher, but this is what I’ve come to believe.

I also believe a natural lifestyle goes a very long way in preventing laminitis. This means allowing horses to have friends, forage, and freedom to move. The horses I’d been observing over the years have all three, and this is why they haven’t foundered.

Fortunately, I’m not the only one who sees it this way.

Several years ago, I bought a book by Joe Camp called Horses Were Born to Be on Grass, which helped to confirm some inklings I was having at the time. In this book, Joe documents his move from the desert lands of California to ‘Founder Valley’, Tennessee. It’s an experience he’s also written about in several articles, including one published in The Horse’s Hoof. Here’s an excerpt on Joe’s thoughts about ‘Founder Valley’ from that particular article:

I was worried about it to be sure, but I had done enough study of horses in the wild to feel that something was amiss with the local logic. It’s more complex than just sugar in grass. All grass everywhere in the world generates sugar. Can soil alone cause an over abundance? And how much does lots and lots of movement play into digestion and metabolism? Can supplements balance other things that if left unbalanced would be bad for the horse? And how much can stress from confinement and human-adjusted lifestyle play into metabolism imbalances. I didn’t know, but I was already researching to find out. One of the points of moving here was to be able to truly let the horses live like horses. Like they were genetically evolved to live. 

Joe would go on to learn that the kind of pasture grass was extremely important when it came to preventing laminitis. Native grasses which weren’t treated with chemicals were much healthier than a single species of ‘improved’ grass which is also often sprayed and fertilized. He also learned the importance of variety. Horses aren’t designed to just eat one type of grass or plant.

photo courtesy of Joe Camp (www.thesoulofahorse.com)

photo courtesy of Joe Camp (www.thesoulofahorse.com)

My thought is (and I’m sure Joe would agree) is that variety will go a long way in ensuring vitamin/ mineral needs are met. And again, I very much believe mineral imbalance or deficiencies play a role in developing laminitis (as well as many other issues).

In the winter, when grass is dormant (or for horses living in pasture with little to no grass), feeding mixed-grass hay, along with a few supplements to cover what the hay is lacking, can achieve the same goal.

But Joe’s experience certainly isn’t the only one which documents that horses living naturally are less prone to laminitis.

I’ve also gotten to know Melanie Sue Bowles, the founder of Proud Spirit Horse Sanctuary. Melanie and her husband, Jim, currently keep around fifty horses on over one hundred acres of lush pastureland in Georgia. Here is what she had to say about her experience (or lack, thereof) with laminitis:

Proud Spirit Horse Sanctuary has been in operation for twenty-five years. We’ve intervened on behalf of hundreds and hundreds of horses, with many coming to live out their lives in our herd. The bedrock of our work is to provide as natural a life as possible, with wild horses as our model (without the breeding). Our rescue horses function as a herd, turned out on over 100 acres 24/7/365, unless one is injured or ill. They traverse grassy pastures, mildly rocky ground, and some sandy areas to reach water.

Our horses receive no processed grain. They have access to forage 24 hours a day, and thrive on grass and/or quality hay during dormant months. Over the years, we’ve taken in horses who had suffered founder before coming to us… we have never experienced one of these previously foundered horses RE-foundering. We credit this to a natural lifestyle.


photo courtesy of Melanie Sue Bowles

Yet a third example of horses who don’t get laminitis is the herd of semi-feral ponies kept for research purposes by the University of Pennsylvania. This herd lives on 40 acres of good pasture and has thrived since 1994. This is what the researchers say on their website:

Perhaps the most striking overall observation is that with modest preventive health care, minimal supplementary feeding in deep winter, and almost no other veterinary care or human intervention, these ponies thrive nutritionally and reproduce prolifically.  Mares are continually fertile, have very little reproductive wastage or difficulty, with no need for veterinary intervention.  Hoof health remains excellent in most cases with minimal need for hoof trimming or other care.  Lameness and colic are almost non-existent.  Laminitis has not occurred in any case in the 11 years of the project. 

semi--feral ponies

photo courtesy of Dr. Sue McDonnell

I recently checked in with Dr. Sue McDonnell, who helps to oversee this herd, and she relayed that the ponies are still doing well. There are currently 118 in the herd with ten foals yet to be born this year. They still have not had one case of laminitis. (You can learn more about these ponies in this video.)


So, my hope is that more researchers will take notice of horses like the ones I’ve mentioned above–the ones living more like the way horses are meant to live–in a herd, on plenty of land (or on a track system) which promotes movement, and without so many of the stressors which are commonplace for other domestic horses.

To me, these horses are proof that laminitis doesn’t have to be one of those sad facts of life.






Hi! My name is Casie Bazay. I'm a mom, a freelance writer, and a certified equine acupressure practitioner.

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6 Responses

  1. Jürgen Grande says:

    Hi there!

    The clinical appearance of lamitis being properly described, the biochemical process has not been, yet. Robert Bowker, Chris Pollitt (et al.) have revealed lots of new insight, but research is not at an end at all.
    20 years ago proteins were considered to be the triggering factor. Meanwhile fructan bears the same role, but some people say there’s zero evidence. Latest investigations pinpoint inulin, a short-chain sugar in broad-leaf plants and thistles.
    In my humble belief there can’t be a mono-causal reason for laminitis (i.e. true laminitis, not to confuse with mechanical founder). My own experiences over the years with horses tell me a very clear strategy:
    – Keep your horse unshod
    – Apply proper hoof care (my personal recommendation: follow Pete Ramey’s notions)
    – Don’t put your horse in a box
    – Make sure your horse has mates and companions of his own species
    – Be a good human companion #1 (no stress, don’t rush, no adrenalin)
    – Be a good human companion #2 (patience, empathy, appropriate communication)
    – Be a good human companion #3 (knowledge aka savvy)
    – Don’t “de-worm“ blindly (make a lab exam to show whether necessary)
    – Don’t overdo vaccs (often no reason for it)
    – Don’t overfeed your horse (if he’s kept somehow “naturally” he’ll take what he needs)

    In a nutshell: keep your horse as near to feral conditions as possible. That’s all.

    My horses eat grass all year long. Even in the “dangerous” months of winter when short grass is “stressed” underneath frosty snow layers, high in sugars. My horses additionally get 24/7 hay in nets, little supplements (based on alfalfa), brewer’s yeast and fresh garlic. I don’t feed any grain.
    There’s no case of laminitis yet. Concerning standard diseases (abscesses, colics etc.) ditto.

    I think Casie is on the right track.
    And she’s not alone.

    Kind regards
    Jürgen (from Germany)

  2. Jenny Gomez says:

    Hi Casie,

    I am a hoof care specialist (barefoot trimmer) in Northern California. I read this article with great interest as I am experiencing a number of horses on my roster that have “Spring laminitis.” I have been researching everything I can find to figure out why some horses end up with it and others don’t. I have situations where four (or more) horses all live in the same environment and two or more will be affected. Given that these horses all get the same feed, grazing opportunities, ability to move freely, and live fairly natural and stress free lifestyles, why is it that only some are affected? Most of these horses only have the variation in the spring grass as a component. It’s possible that their mineral intake is out of balance, but again, all of the horses get the same treatment. Any insight into this for me would be ever so appreciated! Just hoping to fit a piece of the puzzle together!

    • Casie says:

      Hi Jenny,
      I certainly don’t have all the answers, but my guess would be that individual horses handle toxins and stressors differently. Some horses don’t seem to be as affected by vaccines, chemical dewormers, chemicals sprayed on pastures, etc., while others are. Are the horses who developed laminitis the older ones in the herd, by chance? I’ve had more vaccine reactions and immune issues in my older horses, so I would think they would also be more susceptible to laminitis.

      Thanks for reading!

  3. Clissa says:

    What an intriguing issue laminitis & founder are & as usual Cassie, you have given us a very thought provoking article.

    I have had personal & ongoing founder & laminitis experience during the last 10yrs.
    I moved to this 16acre creek flat property 10yrs ago from a 40ac rough & hilly property where my horses roamed free in all seasons with minimal supplementary feeding & kept barefoot even when showing & working.
    I had mostly quarter horses with a couple older Arab/Qh cross types, all very old genetics including a very old QH stallion & his progeny.
    As soon as I moved here I began to see hoof changes in the form of heat that progressively migrated down the foot as it grew until the whole foot was hot. I was still not supplementary feeding until we were in drought whereupon the grass quickly disappeared & I had to buy in hay & processed feeds.
    The oldest horses were euthanatized due to extreme age leaving me with just 3 teenage horses on the 16ac property rotating through 3 x 5ac paddocks while the remaining 1.5ac is house yard & orchard.
    One QH foundered completely & I was lucky to save him. He now has no digital cushions so is unrideable but still a good paddock mate but I have to be very careful with his feed management.
    The others osculate between occasional mild laminitic episodes & sore feet but also show sugar related body scores & fat deposits even though I rarely feed supplementary feeds these days & don’t fill troughs (unless the dams run dry) causing them to have to walk to the dam a few times daily which gives them some exercise at least, nor do I fertilize the pasture, instead rotating them through the various paddocks.
    I think my older arab & QH genetics meant they were not as highly bred as the QH gelding that foundered because he was not one of my breeding. He has far more modern genetics & cant handle sugars at all. He also has a very swollen sheath that many people are now associating with a build up of sugars in the grass.
    So I’m tending to think it might be the highly bred horses that are now more susceptible to sugars because we have selectively bred for bigger muscles, better doers, different body shapes, smaller feet, etc.
    The wild ponies still carry their old genetics. I’ll bet if some young highly bred ponies were added to that herd, laminitis & founder would soon be apparent in those particular ponies & their offspring.
    Also the modern grain & hay has been selectively bred to be a superior feed to fatten cows not be a healthy feed for horses.
    We are being sold processed horse feed concoctions with more oil, energy & protein so our horses don’t loose weight, can work harder & breed better, grow quicker & live longer.
    I think those are all ingredients for disaster for our poor long suffering horse buddies.

    • Casie says:

      Thanks for your comment, Clissa. Sounds like you’ve definitely struggled with this issues. A side note–the pony herd mentioned here are all descendants from domestic Shetlands and similarly sized ponies bought at local auctions, so their breeding would be the same as any of our domestic ponies.

  4. Cathy Dee says:

    We have major issues with laminitis in New Zealand.
    The rise of large scale dairy farming and its associated duo-culture of rye/clover combined with excessive fertilising of land has created a perfect storm of issues for horses – not just laminitis.
    We believe that these issues are due to massive mineral imbalances as much if not more than sugars in the grass.
    High nitrates and the ongoing high potassium/low sodium inherent in vegetative grasses. Clover and other legumes are also major perpetrators in our experience.
    We now keep our own horses on either hay only in large dry lots of tracks or when the season permits, in large paddocks of old style mature grasses, fed 2 feeds a day containing plenty of salt and high spec minerals which change in what we add depending on the weather, the season and what the grass is doing.

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