We had a lot of sickness in our cow herd after calving from 1988 til we got on mineral in 1994. We bought some registered cows and they brought in disease. Our calves would stop running and playing, would have a high temperature. We would doctor them and then in a couple of days their fever would be up again. We had to doctor most of them more than once. They got everything. Diptheria, pneumonia, overeating, you name it. They had no immune system. But that's another story.
We had one old cow we would NOT doctor her calf. Interesting that out of 95% we had to doctor, it was never her calf. She was woofy. She was a smaller Black Angus and she had a topnot between her ears, so we called her 'Woodpecker.' If her calf had gotten sick, it would have died because of her. She put Mr. FH in the pickup and/or under the pickup so many times until he wouldn't even tag her calf. At one point she tried getting in the cab of the pickup. She would even take you if you tagged another calf and her calf wasn't with her. We finally could afford to get rid of her and that was a happy day. Whew! The things you do when you are young and poor.
We AI'd to a bull called RR Traveler 5204. Those were bad even as heifers. They weren't bluffing. They don't get better with age, either. Too bad, they were really nice heifers with terrible dispositions. At our place cattle had a good reason NOT to be bad because we handled them quietly but firmly and with respect.