As in most cattle diseases, prevention is usually easier than a cure later.
The last couple of years we have had a large increase in the wild HEMP crop -- and like most weeds, the darn stuff will grow where you can't toit with a large mower. AS the weeds get taller, the calves walking thru them keep scratching thier eyes or other wise irritating them, and we had a few head get pink eye too.
If we as producers can keep ahead of the taller weeds and grasses by clipping them, it most suredly helps alot. Depending on your locations, pasture mowing is a real effective and good tool in general to help the grasses stay fresh and reduce the unwanted plants from going to seed. Trust me, if I could get to some of these places with a tractor, there wouldn't be any HEMP growing here for sure.
You could go out and spray by hand some of these hard to get to places, but by the time the weeds are receptive to spraying, you would have to worry about killing trees and other good plants too. Catch 22 type of deal.
Of sourse it is always the best ones that seem to get it -- go figure. We do vaccinate as well, but that seems to be only partially effective some years. One thing fur sure, these things we have to deal with -- over time -- makes us all better at what we do!
Terry