Abstract
Japanese Shorthorn is one of the WAGYU, raised in Iwate Prefecture and in other prefectures. We estimated genetic parameters, genetic trends, and genetic gains per year for carcass traits using the data in recent years. Heritability for meat quantity traits were higher than meat quality traits. Heritability of marbling score was lower than other reports. In recent years, genetic trends of the carcass traits were positive trend, except of LMA and RT. Genetic gains per year until 1990s were desirable trend. However, genetic gains trend per year in LMA, RT and SFT were not clear since 2000. Genetic correlation between LMA and firmness was negative, however between SFT and CW, SFT and RT were positive. It was considered that balance of each trait was important for improvement of Japanese Shorthorn.
