Cow-Calf Certification Practice Exam

Which trait tends to be less responsive to heterosis?

1. Mature height

2. Feed efficiency

3. Reproduction

4. Weaning weight

The correct answer is: Mature height

Mature height tends to be less responsive to heterosis because this trait is primarily influenced by genetic factors that do not benefit as much from hybrid vigor. Heterosis, or hybrid vigor, typically enhances traits that are more influenced by environmental factors or those where genetic diversity can lead to improved performance, such as reproduction and growth rates. Mature height is primarily regulated by the genetic makeup of the individual, and while crossing different breeds can lead to some variability, the extent of that variability in mature height is generally less pronounced compared to traits like feed efficiency, reproduction, and weaning weight, where heterosis can significantly improve performance. This is because those traits are affected more by the interaction between genetic and environmental factors, allowing for a greater expression of heterosis when diverse genetic backgrounds are combined.