Comparing AUS-MEAT marbling scores using image analysis traits to estimate genetic parameters for marbling of Japanese Black cattle in Australia

Abstract

The aim of the present study was to evaluate the application of image analysis for Japanese Black cattle in Australia (Australian JB). Therefore, we assessed meat quality using an image analysis method to estimate the heritability of this trait in Australian JB. We photographed the cross-section of the 5th–6th ribs and calculated image analysis traits of 473 and 539 head of Australian JB and Australian JB sire crosses with other breeds (F1), respectively. Least square means of grading and image analysis traits were calculated. We further estimated the heritability of grading and image analysis traits of 414 head of Australian JB. The Australian Meat Industry Classification System (AUS-MEAT) marbling score (6.8) and percentage marbling area (29.2%) for Australian JB were significantly (P < 0.01) higher than those for F1 (4.7% and 19.3%, respectively). Percentage marbling area strongly correlated with the AUS-MEAT marbling score (r = 0.88), indicating that marbling can be improved using percentage marbling area as a substitute for AUS-MEAT marbling score. The head counts of AUS-MEAT marbling score increased in the Australian JB (mode value = 9). The result indicated that the AUS-MEAT marbling score lacks a sufficient range of values to evaluate a high marbling beef breed such as the Australian JB. Further, the heritability of percentage marbling area was 0.54, which is higher than the heritability of AUS-MEAT marbling score (0.23). Therefore, we conclude that determining percentage marbling area using image analysis may prove to be an effective method for improving the marbling of the Australian JB.