So.. my horse can have thrush without it being something to really worry about?
Absolutely and that's the point I was trying to make!
"Thrush" is a generic word we use to describe what is actually a collection of over fifty different types of microbes and spores. Some are bacterial, some are fungal. These microbes are basically scavengers. They exist naturally in most wet environments, seem to prefer dark, moist and warm surroundings and are all anaerobic (they die in oxygen rich environments) to a lessor or greater extent.
I think you could safely argue that "thrush" is pretty common to most domestic horses feet because it's common to the dirt/mud/manure/whatever that they live in everyday. That's why it is so important to maintain the animals feet.
We moved the horse from it's dry, semi-arid natural environment into what are often wet, muddy, microbe infested areas of the planet, exposing the animal to opportunistic bugs it would not normally encounter in the wild.
I've had owners ask me, "Mark, why bother cleaning out the foot when she'll put that hoof right back down in the mud/muck?". It's a good question and makes a good point!
Thrush, like most microbes, has an "incubation" period. It's takes time for the microbes to build their colonies and begin their larger quest in search of food (your horse). When you clean the foot, you're running a bulldozer through the little neighborhoods they've created, disrupting/removing that colony and allowing the "poison" oxygen of our atmosphere to rush in and kill them.
Yes, the horse puts his foot right back into the microbe infested dirt but... They have to start all over again because you broke their happy little home. It takes them a few days, dependent upon temperature and environment, to get a new "foothold".
As I said earlier, this is why it's important that your farrier occasionally trim up the frog, the bars and remove the unexfoliated sole material (using conservative discretion of course). It removes material that can hide the microbes you may not otherwise be able to reach with a hoof pick and it makes it easier for you to do a good job of cleaning the foot.
Remember, we do this because we removed the horse from it's dry, abrasive, firm "natural" footing. Unless you live and keep horses in the deserts of New Mexico or Arizona, we have to compensate for that domestication choice. So clean away you bunch of horse owning "microbe home wreckers"! The microbes will hate you but the horses will love you for it.
I never knew that. I know she had thrush bad a month or two ago because of the warm winter, but I never knew that the black stuff was thrush.
Bacterial and fungal microbes do not multiply as quickly in cold weather. That's why we refrigerate our food, right? A warm winter means soft ground and lots of microbe infested mud/manure/etc packing into the horses nice, warm foot. That "black stuff" is the final stages of decaying filth and it's chalk full of the thrush bacteria. The sticky, oily texture is a bit more disgusting. Microbes, like all living organisms, excrete waste. Wanna guess what much of that filth is? Yep... microbe manure. That explains the smell as the intrusion becomes more significant. Maybe we need tiny (microscopic) little muck rakes and wheelbarrows.
Now imagine what happens when these microbes attach themselves to the whiteline of the horse's foot. (you've probably seen those black dots in the whiteline of your horse, especially right after trimming). Imagine "cold fitting" a horseshoe over that foot and driving nails into the whiteline and through the hoof wall. Are the microbes now nestled safe and warm between the shoe and the foot? Did the nail holes just create a "tunnel" in the hoof wall through which microbes may gain access to the stratum medium of the wall?
Guess what happens when the farrier hot fits that same shoe to the foot before nailing. You see rolling smoke. The microbes under that shoe see Armageddon!
Does your farrier/trimmer bring the foot forward and dress the lower third of the hoof wall? Is he/she managing any mechanical distortion in the foot (flares)? If not, that mechanical distortion can place stress on the juncture of the hoof wall and the sole (the whiteline). The whiteline stretches and tears, creating gaps in the "velcro" like connective tissue. Those gaps are opportunities for microbe intrusion into the hoof wall (whiteline disease).
So it's important not only to keep your horses foot clean, but to also keep them on a regular farriery schedule and avoid the progressive mechanical distortion that almost invariably occurs in most domesticated horses.
My point? There are lots of "thrush treatment" products on the market, all sold to address thrush infection. I've always argued that the best "thrush treatment" is nothing more than good maintenance. Clean out the foot several times per week (at least) and keep your horse on a regular service schedule. You'll still see that "black gunk" in the recesses of the foot but good quality, regular maintenance will keep you and your horse ahead of the game.
I feel smarter now (:
Knowledge is power!