Thrush
Just about every horse owner I've ever dealt with has been told at one time or another that their horse has thrush. If you haven't...well, just wait. If a farrier or natural hoof care practitioner cleans out your horse's hooves and gets out black gunk or after the hooves are cleaned out sees areas of black in the spaces around the frog, he may tell you that your horse has thrush. Or, if the frog is deteriorated, he may tell you your horse has thrush. Then you will be advised to buy one or more of the topical preparations advertised to cure thrush and apply it regularly. In some cases you may be advised to pour bleach on the affected areas.
This happens often; every week I hear from people who have been told their horses have thrush. I think barefoot trimmers and natural hoof care practitioners are most likely to diagnose a horse with thrush, yet farriers do it too. But thrush is actually quite rare, and the great majority of these peoples' horses do NOT have thrush.
What is thrush? Thrush is an infection of the frog by a certain strain of bacteria that cannot survive in the presence of oxygen. These bacteria attack the frog and eat it away. A frog infested with thrush will have the appearance of a sponge. Another way to think of it is that the frog will have little holes in it and will appear somewhat like coral. The frog will be somewhat mushy. I want to stress here that if you've been told that your horse has thrush, chances are that it does NOT. True thrush is rare; it's only the diagnosis of thrush that is hyper-common.
I'll explain later what is probably really wrong if your horse is diagnosed with thrush, but first, let's think for a minute about genuine thrush. The bacteria implicated in thrush are not uncommon. They are around all horses all the time, yet very few horses actually develop thrush, because the horse's body repels the bacteria. They may be there, but they don't infect the frog. You can think of it exactly like your body repels disease causing organisms. Today, just like every day, your body was exposed to numerous organisms with the potential to infect you and cause disease. Yet most likely you didn't get sick today and didn't contract a disease. Your body repelled those potentially disease causing organisms, just like it does every day. They were there but were not allowed to cause problems. That is your immune system at work. A healthy immune system will be able to repel millions of those potential disease causers; only occasionally will it be overwhelmed and you will get sick. However, those with a compromised immune system, such as those with AIDS or those on steriods, have to be very careful about being exposed to disease causing organisms, because their immune system is compromised.
Horses walk around on potentially thrush-causing bacteria all the time, but their immune systems repel those bacteria and keep them from getting a foothold. When the rare case of actual thrush does occur, it is a result of a failure in the horse's immune system. It's important to realize that it is NOT a result of the bacteria. It is perfectly normal for the horse to be exposed to those bacteria. It is perfectly normal for the horse's body to be able to repel them. When actual thrush occurs, what is abnormal is that the immune system is not able to repel them. Thrush represents a problem with the horse's immune system.
Thrush is not a hoof problem and if your horse is one of those rare horses who contracts thrush, you cannot get rid of it by working on the hoof or by putting a topical preparation on the hoof.
But, if your horse has been diagnosed with thrush, don't panic about an immune system problem, because chances are it doesn't have thrush. Black gunk packed around the frog does not indicate thrush. Black areas around the frog that remain after the hoof is cleaned out do not indicate thrush. A stinking hoof does not necessarily indicate thrush. Any horse unfortunate enough to live in surroundings so that it has no choice but to walk over manure will have stinking black gunk packed around the frog. This is nothing more than urine soaked manure plus maybe a little bedding material that has packed in there and rotted. In blunt terms it's a result of your horse living in filth, but it's not thrush. If your horse lives in such an environment, you may be advised to clean the hooves out daily. That might lessen the bad effects of all that rotting filth but won't negate them, and it will lead to other problems as the natural function of dirt packed into the hooves is lost. For more information, please refer to the video Understanding the Hoof--From the Horse's Perspective. Putting on bleach or other topical preparations advertised to cure thrush won't negate the effects of the filth your horses' hooves are exposed to every day, and they will lead to other problems as they will upset the balance of good bacteria. The only answer is to get your horse into a living environment so that its feet do not stay packed with manure, urine, and bedding. Despite what the advertisements for bedding materials and "thrush" medicine say, there is nothing you can buy that will negate the harmful effects of the hooves being exposed to filth.
But, even if there's no black gunk, if your horse's frogs are deteriorated, you may be told it has thrush. Deteriorated frogs are common on horses, but it has nothing to do with thrush. If the hooves are maintained so that the frogs cannot touch the ground, they will deteriorate. That is because the frogs respond like a muscle. Frogs that have no ground contact get no exercise and stress and gradually deteriorate. For more information on this, please read the article on The Frog. You can spend all the money you want to on products advertised to treat thrush, but it will not negate the negative, deteriorating effects of the frog not touching the ground. No thrush medicine will make your horse's frogs healthy--contact with the ground is the only thing that leads to healthy frogs.
To sum up, if your horse is diagnosed with thrush, it's safe to assume it does NOT actually have thrush. What it does probably have are the effects of an environment which allows the hooves to be packed in urine soaked manure and hoof maintenance that does not allow the frog to touch the ground. That is not thrush. Thrush is very rare and does not represent a hoof problem, but a failure of the immune system.
