The main cause of pinkeye in cattle is the ever-changing bacteria, moraxella bovis. Many subtypes of the bacteria can be found even in one infected animal. This can make it difficulty to treat and preventing. Pinkeye can rob producers of weight gain in addition to the labor costs of treatment.
Source: Drovers CattleNetwork, August 17, 2016.
Vaccination, fly control, environmental control and nutrition are all mentioned in the context of prevention.