THRUSH? Or ... and ... what?

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Today's topic is inspired by a lady who asked me about "Interbulbular Dermatitis". 

If you've not heard of that, the simple description is ... Thrush. 

However, note the name ... "interbulbular dermatitis". 

"Interbulbular" = inter-bulbular  and  "dermatitis" = derma-titis. 

Inside (inter) bulbs (bulbular) and skin (derma) inflammation (itis)

When cleaning your horse's hooves, if your horse jumps from the pressure of a hoof pick, it's from thrush exposing sensitive tissues.

If your horse exhibits a crack between the heel bulbs, it is displaying Interbulbular Dermatitis. 

And if your horse has a 'tab' between the heel bulbs, then the irritation and infection is truly quite advanced. 

BUT ... I'm here to tell you that it's NOT ALWAYS JUST THRUSH!  While thrush might be present in the hoof elsewhere, the stuff in between the heel bulbs, MOST LIKELY is going to be YEAST! 

Let's quickly determine the difference in symptoms between Thrush and Yeast: 

THRUSH: Fusobacterium necrophorum  Thrush lives in almost any ground and is not, as previously thought, always associated with poor husbandry.  Thrush exhibits itself with black, tarry discharge with a most foul odor. This bacteria can create a tremendous tissue response and associated pain when it invades normal sensitive tissue. 

YEAST:  Yeast is a microscopic fungus that THRIVES on sugars AND dead bacteria! 

The exudate that you might pull out on the end of the hoofpick would be whitish in color and cottage cheesy looking ... and smelling - "cheesy". Yeast needs to be treated both topically AND systemically. If you've treated for thrush (bacteria) but not for yeast (fungus) then you've fed the yeast and it has proliferated. Yeast loves dead thrush bacteria -- it also thrives in a system that is overloaded with sugar. 

This horse has both thrush AND Yeast: 

The Thrush is hiding in the flaps of the frog and the collateral grooves while the YEAST is hiding in that crack between the heel bulbs. My guess would be when the hooves are cleaned the poor horse flinches away from the hoof pick in between the heel bulbs! That stuff HURTS! 

Here is a photo of what HEALTHY hoof might look: 

Can you tell the difference?  See how the central sulcus is just a mere 'thumbprint' in the back of the frog with no "crack" or continuing crack up between the heel bulbs?  This is a nice, healthy hoof. 

When horses' hooves are exhibiting with a toe first landing and apparent sensitivity in the caudal hoof then one must take a good look at what's going on ... do you see black, tar-like exudate when cleaning the collateral grooves of the hoof?  Does it stink? Or is the frog in shabby condition with lots of old flaps and hiding places for Thrush? (Thrush LOVES damp, dark, anaerobic areas to live and flourish). Is there a split between your horse's heel bulbs that is sensitive to cleaning? And, when cleaning out that area are you pulling out white, cheesy like 'stuff' that smells 'cheesy'? 

If so, you have 2 issues going on that must be treated appropriately to save the hooves. 

Bacteria AND Yeast ... 

Both of which can, and do, eat through tissue down into bone if not treated and eradicated in a timely manner. 

Remember, I said that Yeast MUST be treated systemically. That means not just slapping on some antifungal stuff on the hooves but treating from the INSIDE OUT ... through diet!  In addition to an equine species-specific diet, I prefer to use holistic means with essential oils, homeopathics, charcoal, as topicals and immunoregulators. Others prefer using chemical and more traditional means of killing bacteria and fungus. But most do not consider the diet to be problematic when it is ALL-PROBLEMATIC! 

CORRECT trimming and hoofcare is ESSENTIAL to restoring a healthy balance to hoof tissue along with systemic and topical treatments. 

In other words, the WHOLE HORSE must be treated appropriately. 

We'll talk more on this next week ... so stay tuned! 

In the meantime, if you have any questions or concerns about your horse's hooves and possible yeast invasion, please do not hesitate to ask!  


Gwenyth Browning Jones Santagate is the best-selling author of 10 Secrets to Healthy Hooves as well as a noted author for various international equine publications includingThe Horses Hoof, Equine Wellness, Natural Horse Planet as well as a contributing author for the 2001 United States Federal Mounted Border Patrol Training Manual. For the last 37+ years, she has maintained healthy hooves with natural trimming on thousands of horses and specialized in pathological rehabilitation hoofcare for the last 18 years. She and her husband John keep a small herd of their own equine in SW Florida and continue to offer consults for horses in need. For further information please click here:




  • Gwenyth Santagate: October 17, 2017

    Hi Deb … it sounds like a ‘whole horse’ thing … the exercise daily is not doing the job — and it should. But shoulds don’t count, do they? grin … Things are what they are. And the ‘symptoms’ you’re speaking of tell a story of a whole horse deficiency — diet, hoofcare. With hooves that are compromised by thrush and yeast they really do need professional trimming no less than every 4 weeks; preferably, every 2 weeks in order to keep on top of things. Please feel free to email to me: if you’d like to discuss this further. I can help you. :)

  • Deb Toehl: October 10, 2017

    Sorry about the typos…early morning She is NOT ridden much but is ponied for a couple of miles each day.

  • Deb Roehl: October 10, 2017

    This describes my 20 year old Mustang to a “T”. We have been battling he sore feet for about a year now. She has no shoes. X-rays showed Navicular, so we put shoes on for awhile to give support. I have been using a fungus (athletes foot) medicine, and vinegar on the feet, and have cut down any “treats” in her diet. The feet looked good for awhile, but then I have gotten less anal about her treatment and it looks like things are reappearing. Her shoes have been removed and her toes are getting squared off again. She is ridden much, but is ponied for a couple of Mike’s almost everyday, and stands in a small stall with rubber mats and shavings. I would appreciate any help you can offer as to products to use on her. She is one special pony!!

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