After the beef breed record camouflage incident, in December 2005, Omigyu was defined not only as a Japanese black beef brand raised from an excellent calf, brought to or produced in Shiga Prefecture, for the longest period in the prefecture but also as the one whose place of origin can be indicated as 'Shiga Prefecture' under JAS law (Act for Standardization and Proper Labeling of Agricultural and Forestry Products).
牛の肥育履歴偽装事件を受け、2005年12月、近江牛の定義は、優秀な子牛を導入もしくは生産し、滋賀県内で最も長く肥育した黒毛和種でかつ、JAS法に定める原産地表示が「滋賀県産」と表示できるもの、とされた。