Revisiting the Hanwoo Meat Yield Index: A Perspective from Genetic Improvement

다국어 초록 (Multilingual Abstract)

This study aimed to evaluate the limitations and inconsistencies of the current meat yield index used in Hanwoo (Korean native cattle) from a genetic improvement perspective and to propose an alternative index. The current meat yield index is calculated as the proportion of estimated retail meat, derived from carcass traits such as CWT, EMA, and BFT, relative to total carcass weight. Nevertheless, under the current formulation, an increase in carcass weight may unexpectedly lead to a lower yield index. This was reflected in negative correlations between carcass weight and the meat yield index for both phenotypes (-0.325) and genomic estimated genomic breeding values (-0.137). Even in the highest gEBV quartile group for carcass weight, the proportion of animals classified as Yield Grade A remained low (21%), suggesting a misalignment between selection goals and grade outcomes. Furthermore, the prediction accuracy of yield grade using carcass weight gEBV was only 53.0%, whereas marbling score gEBV predicted quality grade with higher accuracy (61.6%). To address this mismatch, we proposed an alternative yield index that excludes dividing by carcass weight, resulting in a simplified formula based on estimated retail meat weight. The new index showed a strong positive correlation with carcass weight gEBV (0.792), indicating a better alignment with selection objectives. These findings suggest that the current yield index inadequately reflects genetic merit and that consumer-visible grades may fail to capture the actual improvements achieved through breeding. The proposed index offers a simple yet effective alternative, improving both interpretability and consistency.