We had an outbreak last year.  We gave them zactran plus a pink eye shot.  Had the vet do a culture and had a special vaccine made for that.  We gave the cows long range plus the special pink eye shot before going to grass.  When the cows calve, the calf will get a pink eye shot plus the long range soon after birth.  Some say to use La200 but when the culture came back, the la200 wouldn't have touched it but the zactran did.  If you can get a culture, might be worth your while.  Mrs.Vogel