When thrush is allowed to take hold, either through lack of detection or poor maintenance, it can literally eat the frog away. Recognizing when a horse has bad thrush and has had it for a long time is surprisingly easy once you know what you are looking for. This article hopes to demystify that process of analyzing your horse’s hooves and shine some light on what is literally an epidemic in the wetter climates.
Here is a quick clip of a horse with very deep central sulcus thrush. As you’ll see, there is a hole in the frog that a hoof pick can get into about an inch or so. To note, this horse is aggressive when asked to move it’s feet, although will move them if need be or if it wants to. Discovering if that is a respect thing or health related thing is for another article but it is something to consider when evaluating if the horse is having pain problems. A horse in pain will very likely be aggressive or resistant to move around.
Now that you have seen how an unhealthy frog looks, let’s talk about how we know that this thrush has been there for a long time and how it has affected the frog over time.
The red circle obviously shows us where the hole is in the frog. This hole went in quite deep and when this hoof gets treated and heals up, likely the whole top layer will shed off. It would be detrimental to the horse if it were to be cut off right now because the layer underneath is just far too unhealthy and young to be out in the elements and it would risk bruising to the inner structure of the hoof. While it would do the horse good to have it all cut off so the inside of the frog could get air and be allowed to dry out, the frog would be so sensitive, it’s not likely this horse would get too far. Frogs do grow back surprisingly quick and can compress and callous up nice and quick if healthy. Booting the horse could be an option, but it’s still likely going to be a couple to a few weeks before a good healthy frog comes in.
The second way to tell that this horse has had this for a long time is to look at the shape and size of the frog and back of the foot. If you look at enough hooves, you tend to recognize a healthy frog by it’s size, color (possibly), fullness and consistency or how hard it is. This particular frog is practically mush. It’s very soft and squishy to the touch instead of being hard and calloused. It also is quite easy to see that it’s very narrow and contracted. This can also be due to poorly trimmed bars as overgrown bars can squeeze out a good frog and damage the underlying structure of it. Kind of like an overgrown callous on the bottom of your foot, it presses on the inner tissues and muscles and is painful.
The whole back of the foot is weaker for this, while the current owner has kept him barefoot for about a year, I think maybe this horse was previously shod for a bit and maybe didn’t have the opportunity to build up his frogs or cartilage in the back of the foot but definitely the thrush has further weakened it all.
With proper treatment and care, even these frogs can come back to full health in about a month. When the new growth comes in from underneath, the old stuff on top will shed off, or be helped off with a sharp knife to have the new growth come through. This should not be done until the frog underneath has grown hard enough to manage being out and landing on the ground. If done too soon, you can further damage the frog and in turn get a cycle of shedding going on which perpetuates the unhealthiness.
Here is a picture of central sulcus thrush. You can see how the back of the foot has a “butt crack” look to it with a deep crease going up the bulbs
Along with proper trimming and removing rotten portions of frog, the recommended treatment is to use White Lightning “soaks”. White lighting is a brand name product for Chlorine Dioxide. There are other brand names or you can buy it bulk by it’s chemistry name. This is very effective for dealing with the whole hoof and does no harm to healthy tissue unlike things like coppertox or copper sulphate or bleach. While those last three are effective at killing the bad fungus/bacteria on the hoof, they are also very good at hurting healthy tissue too. They are used effectively though in the field but there is that caveat.
White lightning can be used in two ways. The first way and advertised way is to mix equal parts of it and vinegar in a soaking boot or bag and then put the hoof in making sure to seal the top to keep the gas in. The gas is what forms when the acid from the vinegar mixes with the White Lightning and it’s this gas that fumigates the hoof to kill off thrush. You need very little to make this happen, a tablespoon or so of both and about 40 minutes to an hour of hang out and do nothing time. This isn’t a soak at all as it can irritate skin and in turn do damage. It’s the gas that does the work.
The other way to use it is to use cotton swabs or make up rounds, soak them in the White Lightning only (no vinegar) and then after cleaning up the frog as best as possible in the central suclus and collateral grooves, stuff them in tight. These can stay in for a day or so, which is about the time you’d take to go back and pick the feet back out to see how it’s going. This kind of treatment shouldn’t take long, anywhere from 1 to 4 times or so.
The other option is Thrush off, which is a topical powder or a mixture of liquid, or even a triple antibiotic with anti-fungal foot cream applied to the central suclus and collateral grooves. Again stuffing some cotton in there after applying the cream can help keep each treatment in there for longer. Each of these do work and destroy the fungus and help the foot heal itself. Time and patience is the key.