I use a product called "Zonk It" on my horses. It's in a white bottle, blue label with yellow writing, which I buy at the horse supply store. I think I've seen it at Petsmart, too. It is a lot cheaper than the other brands and works great. The key is you have to really shake it up good before you spray--it usually lasts for 2-3 days before I have to spray them again, and it smells like baby powder, so that's nice too. It will also kill fleas and ticks (I think) on your dogs.

Here is a link that might be useful: Zonk It

I use a 3-step approach to flies around here.

First off, the horses get sprayed with Equicare's Citronella fly spray. After trying virtually everything the market has to offer, I find that, around here anyway, that's the only thing that seems to work without requiring constant & total saturation. It also repels nighttime mosquitoes. The horses also wear fly masks, & a couple also wear mesh fly sheets.

Second - I have several fly traps placed around the barn - the type you add an organic attractant to along with water.

Third - I receive a monthly shipment of fly predators from Spalding Labs. They're tiny little harmless gnats that prey on fly eggs. I just sprinkle the little gnat cocoons on my manure pile, as well as on any recent "road apple" pies around.

The combination of all of the above leaves the farm & my 7 horses relatively fly-free.

I also use Zonk-it 35 and think it works great.....although you do have to apply it a couple times a week instead of the once every 30 or 31 days that it advertises. You can get it relatively cheaply on-line compared to buying it in a feed/tack store.

Thanks for the info! I'm going to order some of the Zonk-It for the animals. We have a couple of dogs that spend a lot of time outdoors so it sounds like they could benefit from it as well.

This is a little more of a far-out solution, but have you considered keeping a few chickens and letting them range? I have read in so many places that they will eat fly eggs and larvae in the manure and compost heap. Who knows, it could help and plus you could get some fresh eggs in the deal. :)

Even though this summer's much hotter than usual, the fly population isn't that bad here. We have chickens and they love digging up the manure piles and devouring fly maggots and eggs. Only problem is, the cattle HATE the chickens and chase them out of the paddock every chance they get. Just makes the chickens sneakier LOL - Ellen

The first time I visited the stables where my daughters rode I was afraid to inhale - LOTS of flies. They had just brought the horses back following an evacuation from a flood and the chickens hadn't returned yet. Once the chickens returned, though, the flies disappeared. It was actually very pleasant out there even with 35 horses.

Something else that helps is daily cleaning of paddocks and spreading the manure. Don't let it accumlate. We don't have a manure pile, spread it out on the field every day. We don't have the chickens either, I just couldn't deal with them running all over.

Mowing around fields, paddocks is supposed to provide less cover for flies. Of course they will fly a long way if they smell something good, sweaty horses!

Have you tried the rub on fly repellents, some folks swear by them. How effective they are will depend on how sweaty or how often you wash the animals. Repellent has a shorter life on sweaty or washed often, equines.

I do place some of the fly traps around, and we stall the horses daily. Few flies come in the dark barn. Those horses who don't come when called, are sorry pretty quickly! We leave them out a few more hours, flies really chew them up, chase them around. They are NOT slow to come the next time they get called!!
Horses get night time turnout. Mosquitoes bite them but not quite as hard as the flies. I am seeing a lot more gnats this year, lots of scabby bites along the belly line, up in the girth area. I vasaline the scabs, horses love being rubbed on those itchy spots.

Around here the flies are greenheads, deer flies, and the big monsters should be out soon. None of the repellents work for more than a couple hours, often less. All those flies bite pretty hard. The little black biters draw blood too, but just the numbers of them drive you crazy. Summer horse shows are all about heavy fly sprays so horse will pay attention to you. I wash horse on return home, so he doesn't have a skin irritation from repeated applications.

I found a plan for home made fly traps. Use whatever bait you like. He does warn that traps are somewhat smelly with his bait mix. I heard from other persons that beer and egg mixed, or a old piece of spoiling meat in water, makes good bait. Both are easy. These traps looked like they would do a good job, fairly easy to make, not really expensive. I plan to make some, hope they are helpful to you.

Here is a link that might be useful: Fly Trap Plan--Home Made

try this...

http://ufinsect.ifas.ufl.edu/deerfly_trap.htm