Like Flies on a Cow

Driving through the cows the other night, while searching for that hole in the fence that needed to be fixed, I was noticing how bad the flies are on the cows and calves. It got me to wondering, is there really anything that works for keeping the flies under control in your cattle herd? Let's face it; flies are a nuisance.  Nuisance to me and to livestock of all kind.  Even my four year old runs around the house with a fly swatter in hand attempting to kill the buggers!

Producers can put fly tags in their calves during spring working or branding.  How effect is that?  How long does it really last?

Do you use the mineral feeders that have the fly dust back built over top them like a canopy?  Every time a cow comes to get mineral, they rub up under the fly dust bag?

How about the cattle mineral that has fly control in it?  Help control flies from the inside out?

Do you have cattle oilers set up in your pasture for you herd to use?

 
 
Do you spray your cattle periodically as you are rotating pastures?

Have you discovered some biological control that works in your herd?

I am really curious as to what works for you and your herd?  I am always up for learning something new and maybe it's a technique that we haven't tried and may work for us.  Or