Selection of superior breeding stock is effective only if traits are heritable. A trait is heritable if a portion of a parent's superiority in the trait is passed on to its offspring. The most important measure of production for a commercial cattle operation is pounds of calf weaned per cow exposed. Good reproduction is extremely important. In general, reproductive traits such as percent calf crop and calf livability have a low heritability.
Reproductive traits show little response to selection, but they can be improved by crossbreeding.
The relative economic value, heritability, and response to crossbreeding for various types of traits are summarized in table 1. Production traits, such as weaning weight and average daily gain, are also important. These traits can be improved by selecting superior breeding stock. Production traits also show a moderate response to crossbreeding. While carcass traits are important, they have less economic value for commercial cattle operations than reproduction or growth rate.