Jacaranda as a cause of laminitis

John Lawrence

Does anyone have any knowledge of a possible role of consumption of jacaranda tree bark in causing laminitis? I have an elderly rescue donkey with chronic subclinical laminitis and occasional episodes of lameness. She is proven IR. Recently she had a clinical episode at a time of year when there is no fresh grass or any other known source of high levels of non-structural carbohydrates. She had been chewing heavily on the trunks of jacaranda trees. I know that consumption of black walnut wood  will cause laminitis. Could the same be true of jacarandas, even though they belong to a different botanical family?

I have removed her  from the paddock in which the trees grow and she is improving.

John in Zimbabwe

Eleanor Kellon, VMD

I can't speak specifically to the Jacaranda but studies on bark stripping by various species typically reveal that trees with thin bark (like Jacaranda) are preferred and they are often stripped when young and growing. It isn't the bark the animals are after. It's the phloeum in the layers immediately below it which is typically high in sugar; highest when the tree is growing.  This may be predictable by time or year or may vary. For example, growth may spurt after the end of a drought. With black walnut the problem is a toxicity. In this case, it may simply be sugar in an IR donkey.
Eleanor in PA


EC Owner 2001


Hi John,

Welcome to the group.  I see that Dr Kellon has already answered your question about the jacaranda tree bark. 

Additionally, I'd like to give you a rundown of our DDT/E (Diagnosis, Diet, Trim and Exercise) philosophy. 

To get the very best answers to your questions, we ask that all members fill out a case history on their horse.  To do that you need to join the case history subgroup here:


And then all of the information you'll need to fill out the CH is in the wiki here:


If you have any trouble, just ask and help is available.  It can be a bit daunting at the start, but the better we understand your horse’s situation, the better advice we can provide.

In the meanwhile, I'll give you those details about our DDT/E (Diagnosis, Diet, Trim and Exercise) philosophy.....

Diagnosis:  Happy to hear that your donkey is improving since your removed her from the paddock that the Jacaranda trees are growing. Since she is "elderly" and just to ensure we haven't missed anything about how she got this recent episode of laminitis, wondering if you also checked  for PPID?  What time of the year was her recent episode of laminitis--was it during your fall time of year?    I ask because fall is the "seasonal rise" time of year when all equines have a natural rise in their ACTH, but PPID equines have an exaggerated and prolonged rise in their ACTH, which puts them at risk for laminitis.  More information here:  https://www.ecirhorse.org/seasonal-rise.php 

And more information about diagnosis here: https://www.ecirhorse.org/DDT+E-diagnosis.php 

Diet: The ultimate goal is to feed a low carb, (less than 10% sugar+starch) low fat (4% or less), mineral balanced diet.  We use grass hay, tested to be under 10% sugar + starch, with minerals added to balance the excesses and deficiencies in the hay, plus salt, and to replace the fragile ingredients that are lost when grass is cured into hay, add ground flax seed and Vitamin E.  This diet is crucial for an IR horse, but also supports the delicate immune system of a PPID horse.

Until you can get your hay tested and balanced you should use the emergency diet, soaking the hay for an hour in cold water or 30 minutes in hot water.  Then, to a safe carrier (less than 10% sugar + starch) add the other ingredients in weight appropriate amounts as listed here:  https://www.ecirhorse.org/DDT+E-diet.php 

What you don't feed on the IR diet is every bit as, if not more important, as what you do feed!  No pasture.  No grain.  No sugary treats, including apples and carrots.  No brown/red salt blocks which contain iron and sometimes molasses, and interfere with mineral balancing, so white salt blocks only.  No products containing molasses.  No bagged feeds with a combined sugar and starch of over 10% or starch over about 4%, fat over about 4%.  Unfortunately, even bagged feeds that say they are designed for IR and/or PPID horses are usually too high in sugar and/or starch (usually starch), or fat.  It’s really important to know the actual analysis and not be fooled by a name that says it is suitable for IR/PPID horses.

Trim:  A proper trim is toes backed and heels lowered so that the hoof capsule closely hugs and supports the internal structures of the foot.  Though important for all equines, it's essential for an IR and/or PPID horse/donkey to have a proper trim in place since they are at increased risk for laminitis.  Look on the following pages of our website for more information about a proper trim.



After any potential triggers are removed from the diet (and in PPID horses, the ACTH is under control), the trim is often the missing link in getting a laminitic horse comfortable.  Sometimes horses with subclinical laminitis can be misdiagnosed as having arthritis, navicular, or a host of other problems as the horse attempts to compensate for sore feet. 

Boots and pads are an important part of getting the horse comfortable.   Some good choices are Soft Rides and Easy Boot clouds, and Easy Boot Rx's.  There are others, but members here have had good luck with these.




Boots and pads should be used at all times the horse shows signs of being sore. They help both with physically protecting the feet from contact lameness and by helping to improve the mechanics within the foot. 

Would encourage you to post hoof pictures and any radiographs you have in the PHOTOS section of the case history group so we can help you to determine if you have an optimal trim in place. Go to this section of the wiki to read about how to get a hoof evaluation, what photos are needed and how to get the best hoof shots:


Exercise: The best IR buster there is, but only if the horse/donkey is comfortable and non-laminitic.  A horse that has had lamintis needs 6-9 months after a correct realigning trim is in place before any serious exercise should begin.  No exercise should begin while the horse is on NSAIDS as they can mask the pain and allow the horse to do more than he should, damaging the fragile new laminae.  In fact, NSAIDS are not recommended after the first few days of laminitis as they interfere with healing.

Allowing movement around at liberty in a safe environment where there is no grass and she won't get chased by other horses is a safe place to start.  When she is more comfortable, hand walking in long straight lines with no tight turns can begin.  Never force a foot sore horse to move.

That wraps up the basics of our DDT/E philosophy.  There's a TON more information on our website (https://www.ecirhorse.org/ ), in our files and in the archived messages. 

Please sign each time you post with your name (first if fine--thanks for that!), date of joining and general location (thanks for including that!). Once you get your CH done, please add a link to it in your signature as well.  It really helps us to find it faster and answer your questions faster.  You can set up your signature to attach automatically through the "subscription" tab on the groups.io site.

Don't hesitate to ask any further questions you have!  Give us more details and we can help you better!

Maggie, Chancey and Spiral in VA
March 2011
EC moderator/Primary Response

John Lawrence

Eleanor – Thank you for the suggestion that the donkey is attracted to jacaranda bark because of the sugars in the phloem. The bark and underlying wood is very dry and doesn’t taste sweet to me, so I’m not convinced. I’ve always assumed that donkeys and horses eat bark to get roughage, and also as a habit when they are bored. The apparent association between eating bark and clinical lameness in this case may be just coincidental.

Maggie – Your query about PPID is a good one. The donkey’s ACTH was higher in early February (summer in Zimbabwe) than in the other three on the property, two of which also have subclinical laminitis but no lameness at present and are still on the same pasture eating the same trees. Very little information is available on normal levels of ACTH in donkeys, other than that they are higher than in horses. It is now fall here, so the seasonal rise may have precipitated the clinical episode. I have had her for less than a year, and her previous history is vague, other than that she was very obese and her front hooves were misshapen.

The obvious solution to my problems is to take the donkeys off pasture and manage them as you advise, but I got them specifically to keep the grass short. If I’d known when I started how susceptible donkeys are to pasture laminitis I would have got a couple of retired thoroughbreds instead! Now I have grown too fond of them. I have learned how to prevent clinical lameness in my circumstances, but the new donkey is proving a challenge.

Thanks for your help.

John in Zimbabwe

Eleanor Kellon, VMD

The phloem isn't wet. It's a thin layer, first layer of live cells under the bark:


"High" sugar is only 10% to teens, won't taste sweet to you. Agree confined animals may strip bark out of boredom but feral animals show a clear pattern of which trees they will strip and when.

This study, pg 85, found an average donkey ACTH of 24.7 with higher levels in laminitic and previously laminitic donkeys


and noted the seasonal pattern. This one found higher levels (40s and 50s) but no connection to laminitis history and time of year they were tested is not specified:


a third study also found higher levels but without reference to time of year and a collaborative effort between the Donkey Sanctuary in the UK and Liphook Equine Hospital found horse and donkey values essentially the same.  Register here and watch Andy Durham Feb 2012 webinar:


Eleanor in PA


EC Owner 2001

John Lawrence

Eleanor, you were quite right about sugar in the phloem. I chiselled bark off a tree down to the wood one afternoon, and the next morning there were a few drops of sap oozing from the interface of wood and bark at the cut edge that were very sweet to taste. What amazes me is that donkeys, and horses, are prepared to eat their way through up to 1cm of coarse bark to get to a few drops of sugar.


Re normal ACTH values in donkeys, I have been informed that the Donkey Sanctuary has revised its normal values upwards since 2011, but their results await publication.


John in Zimbabwe

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