Definately sounds like a problem cow, and I have to agree with some of the other responses.. she's not worth someone getting hurt over.
Now having said that, I'm going to stick up for the Brahman breed! I have Brahman cattle, and have to agree they are different to handle than others. They will respond directly to how they are treated, and they seem to have a LONG MEMORY. The heifer you have just happens to be a Brahman, but having a Hereford doesn't mean you won't be faced with similar problems. The disposition is an individual trait, not one shared by an entire breed.