According to eminent parasitologist Dr. Don Bliss, PhD., "the best
weapon we now have against the three stages of the encysted small
strongyle is the use of fenbendazole (the active ingredient
in Safe-Guard) in a larvacidal dose as administered as part of an
ongoing strategic deworming program."
Only one over-the-counter dewormer is safe enough to be administered at a dosage sufficiently high to totally stop the encysted small strongyle in all its stages. (Though one other product is somewhat useful, it is not as effective against the dangerous EL3 larvae, which account for about 75% of the infestation.) This makes Safe-Guard the only complete solution.
According to Dr. Craig Barnett, DVM, PhD, equine researchers advise that Safe-Guard is effective against all stages of the encysted small strongyle if given at double the normal dose of 5 milligrams per kilogram.
Best results usually occur when horses receive the Power Dose in the late winter/early spring. (Those in Florida and the Deep South should check best dose times with their local equine practitioner.) "In fact, it's smart to use Safe-Guard Power Dose to launch a deworming program at any time," added Dr. Craig Barnett.