First thing I want to say is "Know your farmers and what kind of cows they have in their pastures."
The cows can change seasonally. Bulls are brought in at different times of the year and can make your trout outing quite perilous.
Just because there is a public fishing sign at the bridge does "not" mean the pasture you are about to enter is safe.
Horses are to be respected and not messed with when fishing.
Not all breeds of cows are aggressive. Some like this one acted like a dog and followed us for a ways.
I did not fish this pasture for awhile due to the bulls in the foreground with the giant horns. A trip to the farmer the day before told me they were very passive and I should not be afraid of them.
Mind your back casts because cows are very curious and could ruin your outing with a giant hook up.
Cows are good manicures of streams this time of the year when weeds are typically high and make your streams impassable.
Bulls are to be respected and given a wide berth. Also pay special attention to mom's with calves. They can be quite protective.
Be respectful of farmer's fences and gates.