We used a product called 'Buzz Off', it worked with one application, it is specific to horses. It's a pour on and you would go from their poll to their tail. One thing was that it made the hair fall off where it was applied-but the hair was falling out anyway. We would go on the side of the neck to miss the mane.
It worked so good we cannot get it here in Montana any longer. Go figure.
Please be careful mixing products.
Some animals might have sensitive skin and the products could burn them. Test a small area first and wait about 30 minutes to see if there is a skin reaction with any product.
'Pouridon' also works well on equine lice and I think we only do one or two applications following up with the ivermectin.
Keeping it simple works for me.