I never buy a bull without seeing a recent semen test. That and a scrotal circumference over the breed minimum (along with the usual criteria of conformation and EPDs). The people I buy from guarantee their bulls to be breeding sound, but then they also have a vet test before their sale dates. No complaints so far.
One of the best Charlois bulls that I have came from a breeder who's ethics I wish were followed by more people in the purebred industry. If a male calf needs assistance either during the birth or to get on the teat, they band him. It sure shows in the bulls that they market. I had one bull of theirs seperate with a small group of 25 cows, and the next spring I was sure impressed by the vigour in those calves that he sired. Not one assist either delivery or sucking and the calves were just what the cow could comfortably deliver...ie. 1600lb cows gave birth to 120lb calves and 1300lb cows gave birth to 105lb calves. Grew like weeds, too. Gotta love it.
Dcara, sounds like that poor bull was worked too hard. Bet that guy would have tried to return him after the breeding season was done no matter how good that bull looked.
Take care.