Anyhow, I had the Vet come and have a look at him. He said the bull was very healthy, but possibly just a little young, so he gave me some pills to feed him once per day.
The bull started to service the cows within two days, all my cows! He even broke through the fence and bred with all of my neighbor's cows! He's like a machine.
I don't know what was in the pills the Vet gave him ............ but they kind of taste like peppermint.