Gaining control of flies in a livestock facility is extremely difficult. Depending on the size of the facility, an aerial fog with a pyrethrum based insecticide such as Riptide, or a synthetic pyrethrum such as Vector Ban Plus is probably the only thing that will get you any relief, and then it will be short lived. The facilities that I am aware of that get the best control are those with fly misting systems involved. What a fly misting system is comprised of is a series of misting nozzles that completely encircle the facility (every 10 or so feet). These misting nozzles are attached to a holding tank (pyrethrum) that has a timer and a pump. The system dispurses pyrethrum and basically mists the entire area several times each day.
These systems were first designed for flies, but were later modified to kill mosquitoes. Mosquito misting systems in back yards and fly misting systems for barns and livestock facilities are the same thing. Here is a link to our website for Mosquito misting. Just think about this same system being installed inside the facility. http://www.dfwpest.com/dallas-mosquit...
If you need more information, let me know.