I personnelly like tetradur. it is an effective 7 day pinkeye treatment. a couple of vets in ND i interned with really liked it and used it a lot. another thing would be to cover the eye with a patch. this would prevent/lessen the spread. however, my first question would be have you introduced any new animals. to not have it ever, and now all of a sudden, I would look at what has changed. my dad got it in his cows a couple of years back and it took vaccinating and treating the calves for about two years before we started to see it go away, but his started as a major outbreak (~75 % of calves affected). I don't like mixing both oxytetracycline and pen. so would probably treat with only one not both drugs.
