From my own experience, I can't say that I've ever seen cattle eat jimson weed. Simply handling the stuff leaves a smell that is hard to remove. It wouldn't seem to be very tasty. But who knows what an animal stressed with hunger might eat.
Did a quick search, and it wasn't Jimsonweed, it was White Snakeroot. Abraham Lincoln's mother died from milk tainted with it. Sounds like laws were passed about fencing cattle in as a result, since they got into it running free range, it grew in forested areas.
Human tastes are not necessarily shared by animals. For instance, goats like the taste of poison ivy.