Which of the following are examples of highly heritable traits?

• A. Height, length, backfat
• B. Reproduction, health, survival
• C. Bone and fat content, height, length, backfat
• D. Milk production, fleece weight

Answer: (C)

Heritability is about how much genetic differences among animals contribute to the variation we see for a trait. Highly heritable traits show that genetics largely determines the differences, so selection on those traits yields strong genetic gains with relatively less influence from the environment.

Height, length, backfat, bone content, and fat content fit that pattern. These are classic body-measurement and composition traits with strong genetic control, so they’re consistently highly heritable. Reproduction, health, and survival, on the other hand, are much more influenced by environment and management (nutrition, disease exposure, stress), so their genetic contribution to variation is relatively small — they’re not considered highly heritable. Milk production and fleece weight can be moderate to high in some contexts, but the strongest, most consistently highly heritable set here is the group including bone and fat content, height, length, and backfat. That’s why this option is the best choice.