I was given a 17yr old paint mare, as a pasture buddy for my horse. She has an old injury behind her front lt knee. No hair, alot of scarring (not lame), has just been eaten up by flies! When I got her, she was covered with bloody scabs/bites, and down her cannon's was black from fly poo, along with bloody sores from bites. I use Bronco fly spray on my other horse, after cleaning her up good, doctored it good, sprayed her twice a day, some help, but not much. Still being eaten up. So I got some Absorbine Ultrashield EX. It is wonderful! States it should last 10-14 days. It lasts about a week for her, with just a few flies buzzing around! Leg already looking so much better.
So, long story short! Get some Absorbine Ultrashield EX if you need something stronger! It was $20 for a 32oz spray bottle, but so worth it!.