Maybe my horses are weird but I swear that NONE of the fly spray stuff i've ever used works longer than 15 minutes!!!!
I was thinking about this today as I applied Wipe to my horses for the first time this season. That's what I've used for more years than I choose to remember. NOT the spray on. The old fashioned "wipe on" Wipe. And Farnam Swat ointment around the face, ears, chest, and feet. They actually line up for their "treatment". Then dance off to pasture.
The only thing I ever use on the dogs is Avon Skin So Soft applied VERY lightly with a soft cloth.
I have also been purchasing the Fly Predators from Spalding for the last three years.
(Two days ago I woke to snow on the ground. Today - flies!)