Developing an Equivalency Between Canadian and Japanese Grading Systems

Background

Japan is Canada’s second largest beef export market after the United States. Although Canada supplies only a small fraction of the Japanese beef imports (8%) compared with other countries, the Japanese market is significantly profitable, generating some $ 195 M into Canada’s beef revenue exports.  In Canada, along with most other countries, carcasses are graded between the 12^th and 13^th ribs. In Japan however, carcasses are graded between the 6^th and 7^th ribs. Currently countries have compared directly between the two locations. For example, if it graded choice in AAA in Canada graded between the 12^th and 13^th rib it would also be considered the Japanese equivalent of choice. But previous studies have shown that marbling increases further up the loin, therefore there is more marbling between the 6^th and 7^th rib, meaning we may be underestimating the grade of our Canadian beef in these markets.

Objectives

• To determine the variability of marbling content and the marbling pattern between the Canadian (12^th-13^th) and the Japanese (6^th-7^th) grade sites in carcasses at the top end of the marbling range (high AAA or Prime).

• Develop a classification system to segregate carcasses into Japanese grades using data collected at the Canadian grade site

What They did

This project looked at the variability in grade between both sites and developed an equivalency between the Canadian grade at the 12/13 rib and what the Japanese grade would be at the 6/7 site. Carcasses from 209 animals raised to achieve Canada AAA or higher were slaughtered and carcass images were collected. Carcasses were then graded both at the Japanese grading site between the 6^th and 7^th rib as well as the Canadian site between the 12^th and 13^th ribs. From this data researchers developed a calculation that will be able to predict what the Japanese grade would be based on how it Grades on the Canadian system. Researchers also collected additional data on grades of other muscles to correlate those with the grade at the Canadian site as well.

What They learned

The present results suggest that AAA quality grades are comparable to a JMGA 3 and JMGA 4 Japanese marbling quality grades. Specifically, high Canada AAA grades (USDA Modest and Moderate pictorial standards) were comparable to a high JMGA 3 and low JMGA 4. In turn, carcasses classified within the Canada Prime quality grade were mostly comparable to a high JMGA 4 and low JMGA 5.

The applicability of these results in practical operations might be the use of Canadian grades to predict and segregate those carcasses that potentially could achieve JMGA 3 to low JMGA 5 Japanese marbling grades. In this sense, previous studies in the literature along with the present research have shown that Canadian AA and AAA quality grades were comparable to a low JMGA 3 and to a high JMGA 3 (or possibly low 4) Japanese marbling quality grades. Furthermore, the results of the present study have suggested that high Canada AAA grades (USDA Modest and Moderate pictorial standards, marbling scores of 500 and 600 respectively) are comparable to high JMGA 3 and low JMGA 4 (Suppl. Table 3). In turn, carcasses classified within the Canada Prime quality grade were mostly comparable to a high JMGA 4 and low JMGA 5.

The frequency results of the present study suggest that Canada 1 retail cut yield class is comparable with JMGA A, whereas Canada 2 and 3 are highly comparable with JMGA B. These results also show that Canada 4 retail cut yield carcasses are prone to be qualified as JMGA B, whereas Canada 5 and Japanese estimated yields showed inconclusive results with carcasses eligible either as JMGA B or JMGA C yield classes.

What it means

The results of this study suggest that AAA quality grades are comparable to a JMGA 3 and JMGA 4 Japanese marbling quality grades. Specifically, high Canada AAA grades were comparable to a high JMGA 3 and low JMGA 4. Carcasses classified within the Canada Prime quality grade were mostly comparable to a high JMGA 4 and low JMGA 5.

Most of the carcasses within the Canada 1 retail cut yield class were comparable with JMGA A, whereas Canada 2 and 3 were mostly comparable with JMGA B. The results also showed Canada 4 retail cut yield carcasses prone to be qualified as JMGA B.

The results of the present study suggest potential feasibility of Japanese quality and yield traits predictions using camera vision systems variables.