We actually prefer that there are cows in the pasture where we keep bees as they keep the weeds and grass down and rarely cause a problem. One big difference, though, is that they are on pallets of four and not standing alone. They will almost always coexist just fine through the summer months. Wintering can be quite another story, though, as they are unable to defend themselves when the bees are clustered. Watch out for the "greenies"!
"Ve are too soon olt und too late schmart."- A nameless German philosopher