I have had good results from rubs with dangling "flypps" both hanging across the entrance to waterers where possible and even just strung between two wood posts in a pasture. Cows seem to know that these will make them more comfortable and will seek them out and just stand under a rub some times.

Douse the rubs about weekly with a permectrin/diesel mix by pouring from a gas can. Cows and most calves have also had my vet's recommended pinkeye shot at workup in early summer.  No pinkeye problems yet (knock on wood) on 47 head total in a tough pinkeye year. I think a key to fly control is rotational grazing and occasionally dragging or clipping pastures as the cows leave. My clipping mower is a flail with a roller that spreads manure piles. However I've done very little clipping this year.

P H White rubs