by Heath Kizzier | Sep 16, 2022 | Heel Cracks, No Thrush, NT-Dry - AKA No Thrush, Pro Tips
Welcome. This is Heath, Four Oaks VP.
You are likely here because you spotted one of our No Thrush Powder posts online and now recognize that your horse does, in fact, not only have a heel (sulcus) crack between the heel bulbs but also has softer than normal heels.


This is a major warning sign that there is an active thrush infection occurring right now.
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Below there is a link to learn everything there is to learn about sulcus thrush. But here I want to show pictures and make sure that folks are taking care of these heel cracks now – instead of waiting for the wet, cold, muddy months. It is FAR easier to deal with this 30-60 day treatment and regrowth process while wearing a t-shirt and jeans, versus three layers of shirts, a winter coat, and a headlight with waning batteries.
On this page, you will find a few customers’ before and after photos. You will find dozens more here on this site, and on our Facebook page. Notice that we want a “Dimple” in the heel. NOT a “crack.” If a horse has a sulcus/heel crack, it is guaranteed that bacteria will gravitate to that warm, moist, airless area.
An old farrier once gave me a perfect analogy.
He asked, “What happens when you mow your lawn and you take the clipping and spread them out in the sun?”
I said, “They dry up and blow away?
“Right,” he said. “Now, take that same bag of grass clippings, put them in the trash barrel, and close the lid. What will you find in three days?
“It will be a smelly, slimy, green-goo mess.”
“Yup,” he nodded.”That’s exactly what sulcus thrush does inside those heel cracks.

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Finally. Before I sign off, I know there are some of you living in warm, dry climates saying, “Yeah, my horse has a heel crack, but the frog and sole are rock hard! “
This may be true at the moment, but I guarantee you that thrush bacteria WILL get inside any open heel crack and it WILL ultimately cause multiple cases of sulcus thrush a year. Think about it. All it will take is for the horse to step in the puddle you made when you forgot to turn off the trough hose. That moisture activates the bacteria inside the crack, and Bamm, suddenly your horse is mysteriously “off” and you can’t figure out why.
Remember: Sulcus thrush hides in the heel so you can’t see it or smell it. Often you won’t even know it’s there until the horse gets a massive case and it becomes abundantly clear that SOMETHING is wrong with that heel!
Sulcus thrush happens at ANY time of the year.
Now, here is the link to the full Sulcus thrush story, as well as the application pro tips for No Thrush Powder to get the best and fastest results.
Everything you need to know about Sulcus Thrush and Heel Cracks!
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by Heath Kizzier | Apr 3, 2022 | Heel Cracks, No Thrush, Pro Tips
DANGER…A HEEL CRACK is a WARNING SIGN – Thrush Alert!
Hi, I’m Heath Kizzier, VP of Four Oaks Farm Sport Horse Rehabilitation and Reconditioning Centre, and Four Oaks Products. The cover photo above is the same horse Before / after treatment with No Thrush Powder (AKA NT DRY in Canada and EU) The dimple in the heel on the right is what we want. Let’s look at another before / after example below. These were provided by Josephine Trott, PhD UC Davis during a clinical trial of No Thrush powder, [Published in the Horse’s Hoof Magazine, Issue 41- Winter Issue 2010]
NO THRUSH Powder Photo Journal – 37 Days Total

Below we will discuss how to fix this, but first, let’s discuss what a heel crack (Sulcus Crack) is:
A “heel crack” (an opening into the sulcus) is the number one warning sign of thrush. These cracks are not natural. In fact, they are wounds created by bacteria as it seeks a way to get inside the foot. The tissue between the heel bulbs is soft and pliable, so the bacterium burrows in and creates a breeding ground. This breeding ground is warm and moist inside, so until we completely eliminate the crack, we should expect a thrush invasion at least 3-4 times per year.

Normally people only treat for thrush when they see and smell the “black goo.” But with sulcus thrush (thrush inside the crack) you can’t see or smell the goo – so you literally don’t know it’s in there. Often, though, what you do know is that your horse is mysteriously going “off” several times a year. It “comes and goes.” Perhaps you start treating muscles, hocks, and stifles, but the horse is still just… off!
In the case of sulcus thrush, the horse is Off because his heel is infected and he is walking with a toe-first landing. He can’t land on his heel. If he is a barrel horse or jumper, (or any sport horse), he absolutely can not perform at his best because he can’t properly plant his foot in the sand.
The result of toe-first landing???
That barrel horse will take wide crow-hopping turns, ruining your time. The racing thoroughbred must shorten his stride to avoid the pain (not good in a race!). The worst scenario is for jumpers and eventers. Every time that horse takes a jump he will take extreme impact on an improperly angled foot. That is guaranteed to cause soft tissue damage in his legs and back. At our Sport Horse Rehabilitation Centre we’ve seen dozens of incredible Jumpers lose their career due to this.
Click Here to read a True Story on how thrush can easily destroy a career.
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The Good News: There is a solution. We can help regrow the heel back to its healthy (closed) state with NO THRUSH / NT DRY Powder.
Before we start the “Product Talk,” let’s discuss exactly what occurs inside the Heel Crack
WHY ARE HEEL CRACKS THE PRIME CAUSE OF RECURRING THRUSH?
Simple answer… Because when we horse owners no longer see the black goo we stop treating. We think we have beaten back the thrush and we move on to other things. But the truth is, that was a temporary fix because tomorrow a whole new host of bacteria will find its way back in there. There is no way around it. Then, when moisture is introduced via rain, urine, or even water bucket slop-over, thrush has everything it needs to restart the infection process.
WARNING: If you have been using a liquid thrush product, whether you buy it or make it yourself (ie: Bleach, peroxide, alcohol, or vineger) be sure to research the ingredients. If it is caustic, do not use it on sulcus thrush. The term “Caustic” means that the PH level is excessively high or low. If it is caustic it will, of course, kill bacteria – however, it also damages live tissue. EX: Bleach, even a 10% solution, absolutely destroys open tissue.
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HOW DO WE REGROW THE HEEL CRACK?

Photos provided USDF Gold Medal Winner, Kiersten Main. 30 day total NT use.
Now we are going to discuss how to use NO THRUSH ® Powder ( “NT DRY” in Canada) to solve this problem and get from point A – to – Z.
STEP 1. (This will work in all weather conditions, so don’t wait, thinking that a powder won’t do it’s job. It will. )
- Clean the foot with your pick. If the footing is damp, use a rag to wipe off any excess moisture.
- MOST IMPORTANT: Puff plenty of powder into the heel crack. Don’t be shy. Use your hoof pick to wiggle and manipulate the powder all the way inside. Your horse might be sore from the infection. If so, be as aggressive as he will let you. Over the course of a few days, the lameness will lessen as the product dries up the sulcus tissue and you can get more firm with your application. NOTE: We need enough inside the heel to Absorb, Draw and Dry the infected area.
- Puff the powder into the clefts, around the shoe, and then brush it in with your hoof brush. Make sure every bit of sole, frog and heel are scrubbed with powder. Be vigilant with the nooks and crannies and skin tags.
In normal circumstances, it will take 3-7 days to eliminate the bacteria breeding ground. (No more black goo or smell inside the crack.) See the photos below to review a terrible case of Sulcus thrush. (NOTE: You will know when this is complete when the heels become very firm (instead of spongy) and the horse begins walking in a proper “heel-landing” gait, instead of toe-landing.)

DAY 1: On this horse, all this thrush is internal. This is the worst because you can’t actually see the black goo. The actual frog and sole look fine. The thrush lurks below!

DAY 1: Dusting with NO THRUSH Powder. Note how the powder is wicking up the moisture inside the sulcus? It works that fast.

DAY 4: This is great progress. The crack is closing and the heel tissue is reconnecting properly. Also, his heels are much, much firmer. He is no longer lame. NOW ON TO STEP 2!
Step 2.
No! We are not finished. We have eliminated the breeding ground, allowing things to firm up. BUT now we need to get the heel fully closed up and “sealed.” If you stop now, a new troupe of bacteria will jump right back inside the crack.
Fortunately, step two is simple. Just keep dusting. Brush the powder into the frog and clefts and get the powder into the sulcus crack. Dust 3-4 times a week until the crack heals over. With a typical case, this should take 30-60 days, depending on how deep the crack was. One note on this… If you have been previously using a caustic thrush product, it will have damaged the internal tissue. This means that it will likely take a bit longer to get from A-to-Z because it takes time for that tissue to recover and become viable again. Just be a bit patient. After working with thousands of thrush cases I have never seen a sulcus crack that did not properly regrow. NO THRUSH® [ NT Dry] will also allow the clefts regrow. A horse prone to thrush will almost always have collateral grooves that are too deep around the frog. Be sure to always dust the clefts as well as the heels. NT will allow cleft regrowth. [Quick note. Notice I made the statement about that NT will “allow” the clefts to grow. NT Dry does not Make tissue grow, it Allows it to grow.
Step 3
PREVENTION:
Thrush is not “curable.” Once a horse has thrush, he is susceptible. When we look around our barn, it’s obvious: Some horses get it, some don’t. So once we have eliminated the active thrush and repaired the heel crack, it is good practice to continue using NO THRUSH® on a regular basis (We recommend once-per-week. and a bit more often in wet conditions to keep the frog and heel firm). The powder will keep your horse’s feet healthy and firm, and thrush-free. We have 70+ horses and dust every horse every Friday, no matter what. Friday is known as “Dust Day.”
ESSENTIAL HEEL CRACK PRO TIPS. For some excellent Pro-Tips and even more education, jump over to this post. If you plan to go after your horse’s heel cracks, you will want to read this so you know exactly what to expect.
SOME FINAL WORDS:
Once we come to recognize the patterns of thrush and frog disease and understand how the heel crack plays a crucial role, we will catch the warning signs far in advance. We will readily notice gait changes and temperament changes. In short, we will become proactive instead of reactive. This proactive attitude will save time and money. A year’s worth of NT maintenance is far less expensive than one call to the vet.
Thanks for stopping by. I hope this was helpful. If you are struggling with this problem and have questions, Call us. I’m pretty sure we can help. With over 70 horses at our Four Oaks Farm Sport Horse Rehabilitation and Reconditioning Centre, I’m pretty sure we have seen it all.
Cheers
Heath Kizzier
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by Heath Kizzier | Jul 14, 2021 | Heel Cracks, No Thrush, NT-Dry - AKA No Thrush, Thrush
This is a real photo. What is it, you ask? Well, we had to do a lot of investigation, asking a dozen vets, and only when we went to the most seasoned farriers did we find someone who had seen it before.
This is what we came up with:
Prior to this picture, this horse had suffered from significant canker. That issue was eventually controlled, and the “normal” canker tissue growth was no longer present in the sulcus. (NOTE: Canker tissue looks like goopy cottage cheese and ultimately overtakes the sulcus and clefts. )
We believe, however, that the abnormal (excessive) keratin production found a new path. Instead of growing under the horn and bottom of the foot, in the anaerobic environment canker prefers, it funneled the tissue grow out the back of the sulcus. The result is fascinating.
This horse was sound and the “horn” did not cause any pain. The horn was firm and substantial. Every 6-8 weeks it needed to be cut off, only to start growing right back again.
This mystery is only marginally solved, so we’d love to hear from you if you have encountered something similar!
by Heath Kizzier | Apr 26, 2021 | News, No Thrush, NT-Dry - AKA No Thrush, Pro Tips, Rain Rot, Scratches AKA Mud Fever, Testimonials, Thrush
Great product!!
December 27, 2020 by JL (United States)
Great product!
May 19, 2020 by Karen L. (WA, United States)
Highly recommend!!
March 23, 2019 by Jan
Will never be without this
January 27, 2018 by Kaykaypee
October 2, 2017 by VICKI (CA, United States)
Verified Buyer
“Great buy”
February 9, 2017 by MYRA K. (KY, United States)
Verified Buyer
“Great buy”
October 3, 2016 by LISA M. (IN, United States)
By far, the best for thrush!
August 10, 2016 by Nemo
July 24, 2016 by Caillou
May 6, 2016 by Kaylyn W.
Love that it’s dry!
January 21, 2016 by Trappersfriend
Love this stuff!
December 16, 2015 by KDW22
by Heath Kizzier | Jul 16, 2015 | No Thrush, NT-Dry - AKA No Thrush, Pro Tips, Thrush
No Thrush – PRO TIP – July 2015… “**Shedding Frog**” We received a private message from a woman whose horse was shedding its frog. The answer is valuable, so we thought we’d share to all….
While frog shedding is normal, if you have never experienced it, it can look scary. In fact, sometimes the entire V of the frog will shed at once, which really looks daunting.
Usually thrush is the procuring cause of the shedding.
Here is why: Thrush wants to invade and live deep inside the heel tissue, and of course you can’t see it or smell it because it is so deep. [This is why we preach so hard about eliminating the heel cracks and deep collateral grooves. These are bacteria access points.] — Anyway, when the thrush has run it course deep inside, this action can undermine the frog.
However, when active thrush is present, the frog tissue will literally hang on for dear-life. The body does not want to allow it to shed because it is the only protection for the soft, tender, and vulnerable tissue underneath. ….
So here is the No Thrush “tip.” —- If you see the frog begin to shed [ perhaps an edge, or even a big section looks to be dislodging and “flappy” under your hoof pick] get aggressive with your No Thrush dustings. Once per day is best. The powder will draw out the deep bacteria and breeding ground and take care of the “thrush” problem. If the thrush was severe, and the frog has been undermined, the rest of the frog may fully shed away. This is a good sign. This is the body’s way of breathing a sigh of relief. It no longer needs to fight the thrush, so the body allows the necrotic/dead tissue to fall away.
But you are not quite done…. Keep using your NT every few days. This will help firm up that new tender tissue and allow it to regrow properly. No Thrush is not caustic, so it will not inhibit natural grow…. As the new frog continues to grow you can slowly back off. The A-to-Z timing will be based on the speed of your horse’s natural growth rate. [usually 20-50 days] No Thrush is not “making” the tissue grow, it is “allowing” it to grow. Meanwhile the powder is protecting the new/tender tissue from being invaded by a whole new round of thrush.
Hope you found this helpful. Learn more about those heel cracks at www.nothrushshop.com