I keep around 40 cows that I need bred. I will make my story brief. Last year I bought an 18 month old bull who was only able to breed 12 cows before I took him to the vet after 4 months and was told he was sterile. I fed him 7 lbs. feed, along with the pasture he and the cows were on each day. He looked to be in satisfactory conditon. I am anxious to get all my cows bred this year. Now my question...Do I buy two yearling bulls, or one two year old to cover these 40 cows. I will be buying an angus bull or bulls to cover commercial cows. The cows are all together in one pasture. I appreciate your opinions as to what to do.