Every 8 weeks, I switch back and forth between Pyrantal and Ivermectin. I use the paste as opposed to pellets. I have been doing this for over 10 years since we got horses. This was what was suggested to us by the breeder of our first horse and it's always seemed to work just fine.
I can't say that my horses don't have ANY worms because they are grazing animals and who knows what they pick up.
What are your deworming strategies and do you think that I am doing the right thing by switching back and forth? Anything else that anyone would recommend? The vet and farrier love our horses because they are so easy to work with and well mannered, overall super healthy equines.