Animal Science Department


Date of this Version



Presented at Range Beef Cow Symposium XXI, December 1-3, 2009, Casper, Wyoming. Sponsored by Cooperative Extension Services and the Animal Science Departments of the University of Wyoming, Colorado State University, South Dakota State University, and the University of Nebraska¬Lincoln.


Copyright 2009, the authors.


Proper management and nutrition of bulls is essential to ensure cow/calf producers maximize reproductive efficiency and genetic improvement of the calf crop. In addition, the herd bull influences overall herd fertility more than any other single animal, and loss of fertility by a bull can cause substantial loss to a potential calf crop. Each cow produces one calf per year; however, bulls should contribute to the calf crop by 25 to 60 times via siring 25 to 60 calves. Additionally, bulls influence their daughters’ production in the cow herd. Therefore, bull selection can be the most powerful method of genetic improvement in the herd, but bulls with low fertility, structural problems and low libido reduce the percent calf crop weaned.