Two years of research with nine herds indicated one of two yearling bulls with a herd usually will sire most of the calves. In six of the nine cases, the bull we pre-evaluated as most sexually active was the sire of the most of the calves. So a brief pre-breeding libido evaluation may help estimate breeding potential. In data from one herd the bull dominant as a yearling continued to be dominant as a two-year-old.
Our data also indicated active breeding yearling bulls easily breed
more than 20 to 25 cows during their first breeding season.