Bulls represent a small percentage of the annual costs of the cow herd, yet the difference in economically relevant traits between good and average bulls can be significant.
To reduce some of the potential risk of introducing new genetics to the herd, making well-informed decisions and utilizing expected progeny differences (EPDs) can help alleviate the risk.
The first step in bull selection requires identifying your marketing goals for the calf crop. If you plan to retain heifers, prioritize some of the maternal traits such as heifer pregnancy and stayability. Weaning weight and milk are also important considerations for replacements, but keep in mind: Moderation of these EPDs is often more valuable than maximization.
If you practice retained ownership, more terminal EPDs such as yearling weight, marbling, ribeye area and other carcass traits should take precedence.
Arguably, the two most-talked-about EPDs include birthweight and calving ease direct for many commercial producers. While birthweight is an indication of what size of calf to expect, it’s only about half of the equation and doesn’t take into account genetic variation and environmental effects on calving ease. Thus, calving ease direct EPD is more valuable, especially for first-calf heifers.
However, reduced birthweights are often associated with decreased weaning and yearling bodyweights, so precautions should be taken with using low birthweight and calving ease direct EPD on mature cows.
Many producers will use a positive calving ease direct EPD bull on heifers for two to three years and then continue to run the bull with mature cows. Use of high-calving-ease bulls on mature cows when it might not be needed often results in decreased pounds sold and, ultimately, money left on the table.
Keep in mind: A balanced approach is more effective than single-trait selection, and many breed associations have multi-trait indexes that combine several EPD traits into a single economic value EPD. While indexes can be helpful, it’s still important to understand the true meaning behind them. Matching EPDs to your environment and production goals are key to the success of your operation. 
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Erika Lundy
- Extension Beef Program Specialist
- Iowa Beef Center - Iowa State University
- Email Erika Lundy
