We just got rid of a terrible case of persistent frog thrush on one of the boys with betadine spray...you can just buy from the chemist thoroughly clean the hoof then spray on and then hold hoof up for about 1 min to ensure it gets into the crevices and put the horse in a paddock with no dam or really muddy areas, do this every day until there is no sign of the thrush, and then use as a mix of two tablespoons of bleach in a spray bottle of water on the soles of the hooves during wet weather as a preventative measure once the thrush has cleared.