What is Heterosis?

Bob Weaber (Kansas State University): Heterosis is really the extra little boost in performance we get from animals that have a genetic makeup that has an origin in more than one breed. So, two or more breeds crossed together produces a slight boost in performance. That slight boost in performance, typically, is in economically important traits and helps us leverage genetic improvement in lowly heritable traits. Heterosis has the tendency to impact traits that have low heritability, or from a genetic improvement perspective, traits that we can't improve through traditional selection tools like EPDs. Heritability describes the portion of variation that's under genetic control. Since we have a number of economically important traits in the beef value chain that are lowly heritable, crossbreeding presents an opportunity to improve those. Examples of those traits might include traits like longevity and fertility that we know have major economic impact in terms of profitability for the commercial cow/calf producer.