I agree with the other posters here about not using cattle products for horses....could get you into bad trouble fast. There are tons of fly sprays for horses available. I've bought them on sale trying different brands and not only have I been disappointed, but managed to burn the horse's skin applying it so liberally...trying to get it on well and last longer...no more. I went back to and only buy WIPE, which is a Farnam product and it still works best. I put it on every evening at dinner time, which helps them get thru the witching hours. For the flies, I use fly masks and those disposable fly traps. I had the horses and the cows gates side by side last year and you know how they tend to hang around the gates, so I put several traps there and ended up establishing a kind of fly trap station that seemed to pull the flies from all around, even the house! Fly populations increase like a rolling snowball as the weather gets hotter, so the sooner you get those traps out, the better. As for the mosquitoes, I just use the WIPE at 5pm and have faith in the West Nile innoculations. I also have applied a long lasting spot on product which comes in a little tube and you pour a line down their spine and the backs of their legs and it really works good..they say for 10 days. I've done it twice this year. I used Equi-spot, which a friend from the States sent me. The first time, the horses were not bothered at all for 7 days, then I had to start in with the WIPE. The second time, it only lasted for 5 days, so either the population is overwhelming it faster as it gets heavier numbers, or the bugs are becoming resistant to it, so I'm laying off of it for a while and won't apply it again until we get into the crunch of summer. It sure is nice to get a break from the WIPE for a few days, though. Good luck!