It's a common hazard in farming. For the testing, you need to bring cattle into a closed space, then walk among them and guide them into the crush. More like force. They get wilder as time passes, until only the hardest ones are left. They're eventually done, and then it's the bull's turn - he's really only possible to force if he half-wants to go anyway, so you send a female in in front of him. But he's still damned hard even with that. Our cattle haven't had their horns cut in donkeys, so that's an added danger.
The only real thing saving our lives is the notion which the cows have, namely that we can hurt them. We couldn't, or at least not in any meaningful way, and this is a reality they become more cognisant of as time passes and, to quote my father, "their heads go up."
To give some family examples - my grandfather was forced into a tree by a herd (not sure how he managed that). My aunt was knocked over and trampled by a cow (skull damage, thankfully not too serious). I've been chased a few times when I was a child - they're more likely to go for children. More recently, as the herd passed through a gate they unhinged it with me standing behind. Thankfully just out of its reach. Just today, my dad was kicked in the knee by a full grown cow, and nearly knocked over by another. He's seventy, so that's not conducive to continued good health.
Granted, in large part the breed of the cow determines its temperament. We have what amounts to a pet Jersey who lets you practically hang from her neck. But, all too often, they combine vindictiveness with power. I have a healthy fear of them in close quarters - one rush and you're dead.
I must also mention that I am confused as to how a calf could physically trample someone to death. Unless you mean heifer, which is a cow which hasn't calved (usually 'adolescent'). As an aside, I live in Ireland, yes. But if you meet someone from Northern Ireland, err on the side of caution - don't mention that fact
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