Comparison of Meat Quality of <I>M. Semitendinosus</I> of Japanese Brown (Kumamoto) Steer Produced by Conventional and Pasture Feeding

We investigated the performance and meat quality of Japanese Brown (Kumamoto) (JB-K, n=3, 8-9 months of age, 311±4 kg of body weight) steers that were raised and fattened by using year-round outdoor grazing and self-suffi cient feed supplies such as corn silage. The steers were grazed year-round outdoors on pasture, predominantly Italian ryegrass in the winter season and bahiagrass in summer without commercial formula feeds. Pasture feeding consisted of two stages, the pasture-rearing and pasture-fattening periods. The daily weight grain (DWG) of steers was 0.40±0.13 kg in pasture-rearing period of 287 days and 1.42±0.35 kg in pasture-fattening period of 164 days, respectively (total DWG: 0.82±0.08 kg, 451 days). Steers grazing in a pasture also consumed corn silage from 19.7±0.6 months of age, and they were slaughtered at 650±22 kg of body weight and 24.7±0.6 months of age. The carcass grades for pasture-fed steers were A-2 (n=1) and B-2 (n=2). Meat quality of M. semitendinosus was compared between pasture-fed and formula feed-fed steers (n=3, 680±54 kg of slaughter body weight, 24.5±0.4 months of age). Pasture-fed steers contained lower (P<0.05) lipid contents and higher (P<0.01) β-carotene content than formula feed-fed ones. We assessed shear-force, oxygen radical absorbance capacity (ORAC) and eating-quality characteristic using taste sensor. There were no differences between two groups in those items during chilled storage. However, both groups showed a significant decrease in shear-force (P<0.05) and increase in ORAC (P<0.05) during chilled storage. In both groups, four measured values (i.e. sourness A, umami, drug like bitterness and bitter like bitterness as aftertaste) of the taste sensor were increased (P<0.05), and among other items harsh taste, sweet taste and ‘koku’ were decreased (P<0.05) during chilled storage. These results indicated that there were no differences in muscle hardness, antioxidant capacity and taste between pasture-fed and formula feed-fed JB-K steers with the exception of β-carotene content.