Cattle can definitely be 'dog broke.' It just takes awhile, as you mentioned and it takes a dog with a lot of confidence and perserverance, or the cows win. We just never had to take our dogs where cattle weren't used to dogs. Having them in those kind of cattle for one day would be really hard on the dog.
There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.