How are your beasts kept, penned in a barn or field ?
I ask because ringworm is usually eradicated by UVrays [sunshine !] and the quick and cheap way to cure them would be run them outside [depending on season of course].
If mites or lice how have they contracted them, have you recently brought in infected animals ?
You will also probably need to disinfect any areas used by them to prevent any future outbreaks but this will depend on the diagnosis.
Good luck !