I think its a simple question. Many people de-worm their horses every eight weeks, or two! There are only so many de-wormers people! Even ask your vet what happens when you use one tube of ivermectin for example. He might tell you how even though you’ve “helped” your horse, the parasites are building up immunity to your poisons and you should switch off de-wormers all the time.
So, the big question here is; Did wild horses get tubes of poison shoved down their throats all the time? NO! They de-wormed themselves! With enough pasture space horses are able to find the plants they need that naturally de-worm themselves. Unless your horses eat exactly where they shit then you don’t need to de-worm as excessively as vets tell you to. Now, if a horse came to me from a stall laden with manure I would worm him, but other then that we don’t worm our horses, and they are just fine. I know that may sound scary to some people but we haven’t had problems.
Notice after you de-worm your horse it starts to get lose stools. This is because the body is so overwhelmed with what was just put into it that it goes on a fit trying to clean its self out. I don’t blame it. Its almost the same thing as eating some food gone bad, you get lose stools trying to clear up your system.
The mind of a horse may be domesticated, but that doesn’t mean the body is. Can we let nature be natural? Just the word “worm” or “parasite” has become such a bad thing. What about the ones that actually aid in digestion? Or those who are completely harmless? You can always get a stool test if you’re not sure, but make sure it tests for everything, many don’t unless you ask. There is a lab in Virginia that tests five dollars per stool and tests for everything, we’d tested all our horses and out of ten only about two had a trace amount of some worms that we were able to get rid of. If anything I would only worm once in the winter when vegetation isn’t available to horses.