@Secondwinded welcome to the CT forum. Please go to your name top right, down to account details and down to location and put in a general area/state... it will show up on your avatar when you post and people can relate better to where you are...
I agree with having him semen tested and possibly getting him collected and semen frozen... Any vet that does ET's should be able to help you out with collecting and freezing semen.
Yep, curious as to how a 15/16 yr old bull never was with cows???? Inquiring minds want to know.....
We used a bull when he was 13 and if it wasn't for the arthritis in a hock joint from having a broken bone 7 years earlier... we would have kept him as long as he was settling cows... but he was having trouble getting up and we did not want him to suffer through the upcoming winter so he got shipped while he was still mobile.
We sold 2 different bulls this past year that were 2012 and 2013 models... one injured his hind foot and it just didn't get better and we knew he would not be able to breed; the other stifled and with cull prices, it was smarter to ship him.
We have one now that passed his BSE last spring that was probably born in 2012... he was a mature bull when we got him in 2016.... really like his calves and have several daughters and grand daughters in the herd. He just came off the last breeding group and had 20 out of 22 preg... so NO COMPLAINTS.
We keep a bull we like, as long as he is fertile and has not become a problem to keep in or a jerk to work around...